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The following commit(s) were added to refs/heads/master by this push:
     new a15e94a  HBASE-26147 Add a dry run mode to the balancer, where moves 
are calculated but not actually executed
a15e94a is described below

commit a15e94a47f06ae665a0c213d092761431e907eac
Author: Bryan Beaudreault <bbeaudrea...@hubspot.com>
AuthorDate: Tue Jul 27 17:25:59 2021 -0400

    HBASE-26147 Add a dry run mode to the balancer, where moves are calculated 
but not actually executed
    
    Closes #3630
    
    Signed-off-by: Duo Zhang <zhang...@apache.org>
    Signed-off-by: Josh Elser <els...@apache.org
---
 .../java/org/apache/hadoop/hbase/client/Admin.java |  40 ++++++-
 .../hadoop/hbase/client/AdminOverAsyncAdmin.java   |   9 +-
 .../org/apache/hadoop/hbase/client/AsyncAdmin.java |  37 +++++-
 .../hadoop/hbase/client/AsyncHBaseAdmin.java       |   8 +-
 .../apache/hadoop/hbase/client/BalanceRequest.java | 114 +++++++++++++++++++
 .../hadoop/hbase/client/BalanceResponse.java       | 126 +++++++++++++++++++++
 .../hadoop/hbase/client/RawAsyncHBaseAdmin.java    |  29 +++--
 .../hadoop/hbase/shaded/protobuf/ProtobufUtil.java |  63 +++++++++++
 .../hbase/shaded/protobuf/RequestConverter.java    |  10 --
 .../src/main/protobuf/server/master/Master.proto   |   5 +-
 .../protobuf/server/rsgroup/RSGroupAdmin.proto     |   4 +
 .../hadoop/hbase/coprocessor/MasterObserver.java   |  16 ++-
 .../org/apache/hadoop/hbase/master/HMaster.java    |  54 +++++----
 .../hadoop/hbase/master/MasterCoprocessorHost.java |  18 +--
 .../hadoop/hbase/master/MasterRpcServices.java     |  34 +++---
 .../hbase/rsgroup/DisabledRSGroupInfoManager.java  |   4 +-
 .../hadoop/hbase/rsgroup/RSGroupAdminClient.java   |  11 +-
 .../hbase/rsgroup/RSGroupAdminServiceImpl.java     |  23 ++--
 .../hadoop/hbase/rsgroup/RSGroupInfoManager.java   |   4 +-
 .../hbase/rsgroup/RSGroupInfoManagerImpl.java      |  29 +++--
 .../hbase/security/access/AccessController.java    |   5 +-
 .../apache/hadoop/hbase/TestRegionRebalancing.java |  27 ++++-
 .../client/TestAsyncTableGetMultiThreaded.java     |   2 +-
 .../hadoop/hbase/client/TestMultiParallel.java     |   2 +-
 .../hbase/client/TestSeparateClientZKCluster.java  |   2 +-
 .../hbase/coprocessor/TestMasterObserver.java      |  13 ++-
 .../hbase/master/TestMasterDryRunBalancer.java     | 125 ++++++++++++++++++++
 .../master/procedure/TestProcedurePriority.java    |   3 +-
 .../hadoop/hbase/rsgroup/TestRSGroupsBalance.java  |  91 ++++++++++-----
 .../hadoop/hbase/rsgroup/TestRSGroupsBase.java     |   6 +-
 .../hadoop/hbase/rsgroup/TestRSGroupsFallback.java |   4 +-
 .../hbase/rsgroup/VerifyingRSGroupAdmin.java       |  14 +--
 .../security/access/TestAccessController.java      |   8 +-
 .../access/TestWithDisabledAuthorization.java      |   6 +-
 hbase-shell/src/main/ruby/hbase/admin.rb           |   9 +-
 hbase-shell/src/main/ruby/hbase/balancer_utils.rb  |  57 ++++++++++
 hbase-shell/src/main/ruby/hbase/rsgroup_admin.rb   |   7 +-
 .../main/ruby/shell/commands/balance_rsgroup.rb    |  22 +++-
 .../src/main/ruby/shell/commands/balancer.rb       |  33 +++---
 hbase-shell/src/test/ruby/hbase/admin_test.rb      |   8 +-
 .../src/test/ruby/hbase/balancer_utils_test.rb     |  78 +++++++++++++
 .../src/test/ruby/shell/rsgroup_shell_test.rb      |   2 +
 .../hadoop/hbase/thrift2/client/ThriftAdmin.java   |   9 +-
 43 files changed, 966 insertions(+), 205 deletions(-)

diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
index 1363605..48893cc 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/Admin.java
@@ -831,7 +831,20 @@ public interface Admin extends Abortable, Closeable {
    * @return <code>true</code> if balancer ran, <code>false</code> otherwise.
    * @throws IOException if a remote or network exception occurs
    */
-  boolean balance() throws IOException;
+  default boolean balance() throws IOException {
+    return balance(BalanceRequest.defaultInstance())
+      .isBalancerRan();
+  }
+
+  /**
+   * Invoke the balancer with the given balance request.  The BalanceRequest 
defines how the
+   * balancer will run. See {@link BalanceRequest} for more details.
+   *
+   * @param request defines how the balancer should run
+   * @return {@link BalanceResponse} with details about the results of the 
invocation.
+   * @throws IOException if a remote or network exception occurs
+   */
+  BalanceResponse balance(BalanceRequest request) throws IOException;
 
   /**
    * Invoke the balancer.  Will run the balancer and if regions to move, it 
will
@@ -841,8 +854,17 @@ public interface Admin extends Abortable, Closeable {
    * @param force whether we should force balance even if there is region in 
transition
    * @return <code>true</code> if balancer ran, <code>false</code> otherwise.
    * @throws IOException if a remote or network exception occurs
+   * @deprecated Since 2.5.0. Will be removed in 4.0.0.
+   * Use {@link #balance(BalanceRequest)} instead.
    */
-  boolean balance(boolean force) throws IOException;
+  @Deprecated
+  default boolean balance(boolean force) throws IOException {
+    return balance(
+      BalanceRequest.newBuilder()
+      .setIgnoreRegionsInTransition(force)
+      .build()
+    ).isBalancerRan();
+  }
 
   /**
    * Query the current state of the balancer.
@@ -2494,10 +2516,20 @@ public interface Admin extends Abortable, Closeable {
   /**
    * Balance regions in the given RegionServer group
    * @param groupName the group name
-   * @return boolean Whether balance ran or not
+   * @return BalanceResponse details about the balancer run
    * @throws IOException if a remote or network exception occurs
    */
-  boolean balanceRSGroup(String groupName) throws IOException;
+  default BalanceResponse balanceRSGroup(String groupName) throws IOException {
+    return balanceRSGroup(groupName, BalanceRequest.defaultInstance());
+  }
+
+  /**
+   * Balance regions in the given RegionServer group, running based on
+   * the given {@link BalanceRequest}.
+   *
+   * @return BalanceResponse details about the balancer run
+   */
+  BalanceResponse balanceRSGroup(String groupName, BalanceRequest request) 
throws IOException;
 
   /**
    * Rename rsgroup
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
index 4a62f02..08de979 100644
--- 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AdminOverAsyncAdmin.java
@@ -374,6 +374,11 @@ class AdminOverAsyncAdmin implements Admin {
     return get(admin.balancerSwitch(onOrOff, synchronous));
   }
 
+
+  public BalanceResponse balance(BalanceRequest request) throws IOException {
+    return get(admin.balance(request));
+  }
+
   @Override
   public boolean balance() throws IOException {
     return get(admin.balance());
@@ -1006,8 +1011,8 @@ class AdminOverAsyncAdmin implements Admin {
   }
 
   @Override
-  public boolean balanceRSGroup(String groupName) throws IOException {
-    return get(admin.balanceRSGroup(groupName));
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) throws IOException {
+    return get(admin.balanceRSGroup(groupName, request));
   }
 
   @Override
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
index a5b1510..c366d3e 100644
--- a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
+++ b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncAdmin.java
@@ -1287,7 +1287,8 @@ public interface AsyncAdmin {
    *         {@link CompletableFuture}.
    */
   default CompletableFuture<Boolean> balance() {
-    return balance(false);
+    return balance(BalanceRequest.defaultInstance())
+      .thenApply(BalanceResponse::isBalancerRan);
   }
 
   /**
@@ -1297,8 +1298,25 @@ public interface AsyncAdmin {
    * @param forcible whether we should force balance even if there is region 
in transition.
    * @return True if balancer ran, false otherwise. The return value will be 
wrapped by a
    *         {@link CompletableFuture}.
+   * @deprecated Since 2.5.0. Will be removed in 4.0.0.
+   *  Use {@link #balance(BalanceRequest)} instead.
+   */
+  default CompletableFuture<Boolean> balance(boolean forcible) {
+    return balance(
+      BalanceRequest.newBuilder()
+        .setIgnoreRegionsInTransition(forcible)
+        .build()
+    ).thenApply(BalanceResponse::isBalancerRan);
+  }
+
+  /**
+   * Invoke the balancer with the given balance request.  The BalanceRequest 
defines how the
+   * balancer will run. See {@link BalanceRequest} for more details.
+   *
+   * @param request defines how the balancer should run
+   * @return {@link BalanceResponse} with details about the results of the 
invocation.
    */
-  CompletableFuture<Boolean> balance(boolean forcible);
+  CompletableFuture<BalanceResponse> balance(BalanceRequest request);
 
   /**
    * Query the current state of the balancer.
@@ -1722,10 +1740,21 @@ public interface AsyncAdmin {
   /**
    * Balance regions in the given RegionServer group
    * @param groupName the group name
-   * @return boolean Whether balance ran or not
+   * @return BalanceResponse details about the balancer run
+   * @throws IOException if a remote or network exception occurs
+   */
+  default CompletableFuture<BalanceResponse> balanceRSGroup(String groupName) {
+    return balanceRSGroup(groupName, BalanceRequest.defaultInstance());
+  }
+
+  /**
+   * Balance regions in the given RegionServer group
+   * @param groupName the group name
+   * @param request options to define how the balancer should run
+   * @return BalanceResponse details about the balancer run
    * @throws IOException if a remote or network exception occurs
    */
-  CompletableFuture<Boolean> balanceRSGroup(String groupName);
+  CompletableFuture<BalanceResponse> balanceRSGroup(String groupName, 
BalanceRequest request);
 
   /**
    * Rename rsgroup
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncHBaseAdmin.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncHBaseAdmin.java
index 8caee48..f0f564b 100644
--- 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncHBaseAdmin.java
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/AsyncHBaseAdmin.java
@@ -694,8 +694,8 @@ class AsyncHBaseAdmin implements AsyncAdmin {
   }
 
   @Override
-  public CompletableFuture<Boolean> balance(boolean forcible) {
-    return wrap(rawAdmin.balance(forcible));
+  public CompletableFuture<BalanceResponse> balance(BalanceRequest request) {
+    return wrap(rawAdmin.balance(request));
   }
 
   @Override
@@ -883,8 +883,8 @@ class AsyncHBaseAdmin implements AsyncAdmin {
   }
 
   @Override
-  public CompletableFuture<Boolean> balanceRSGroup(String groupName) {
-    return wrap(rawAdmin.balanceRSGroup(groupName));
+  public CompletableFuture<BalanceResponse> balanceRSGroup(String groupName, 
BalanceRequest request) {
+    return wrap(rawAdmin.balanceRSGroup(groupName, request));
   }
 
   @Override
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceRequest.java 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceRequest.java
new file mode 100644
index 0000000..e464410
--- /dev/null
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceRequest.java
@@ -0,0 +1,114 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.client;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Encapsulates options for executing a run of the Balancer.
+ */
+@InterfaceAudience.Public
+public final class BalanceRequest {
+  private static final BalanceRequest DEFAULT = 
BalanceRequest.newBuilder().build();
+
+  /**
+   * Builder for constructing a {@link BalanceRequest}
+   */
+  @InterfaceAudience.Public
+  public final static class Builder {
+    private boolean dryRun = false;
+    private boolean ignoreRegionsInTransition = false;
+
+    private Builder() {}
+
+    /**
+     * Creates a BalancerRequest which runs the balancer in dryRun mode.
+     * In this mode, the balancer will try to find a plan but WILL NOT
+     * execute any region moves or call any coprocessors.
+     *
+     * You can run in dryRun mode regardless of whether the balancer switch
+     * is enabled or disabled, but dryRun mode will not run over an existing
+     * request or chore.
+     *
+     * Dry run is useful for testing out new balance configs. See the logs
+     * on the active HMaster for the results of the dry run.
+     */
+    public Builder setDryRun(boolean dryRun) {
+      this.dryRun = dryRun;
+      return this;
+    }
+
+    /**
+     * Creates a BalancerRequest to cause the balancer to run even if there
+     * are regions in transition.
+     *
+     * WARNING: Advanced usage only, this could cause more issues than it 
fixes.
+     */
+    public Builder setIgnoreRegionsInTransition(boolean 
ignoreRegionsInTransition) {
+      this.ignoreRegionsInTransition = ignoreRegionsInTransition;
+      return this;
+    }
+
+    /**
+     * Build the {@link BalanceRequest}
+     */
+    public BalanceRequest build() {
+      return new BalanceRequest(dryRun, ignoreRegionsInTransition);
+    }
+  }
+
+  /**
+   * Create a builder to construct a custom {@link BalanceRequest}.
+   */
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  /**
+   * Get a BalanceRequest for a default run of the balancer. The default mode 
executes
+   * any moves calculated and will not run if regions are already in 
transition.
+   */
+  public static BalanceRequest defaultInstance() {
+    return DEFAULT;
+  }
+
+  private final boolean dryRun;
+  private final boolean ignoreRegionsInTransition;
+
+  private BalanceRequest(boolean dryRun, boolean ignoreRegionsInTransition) {
+    this.dryRun = dryRun;
+    this.ignoreRegionsInTransition = ignoreRegionsInTransition;
+  }
+
+  /**
+   * Returns true if the balancer should run in dry run mode, otherwise false. 
In
+   * dry run mode, moves will be calculated but not executed.
+   */
+  public boolean isDryRun() {
+    return dryRun;
+  }
+
+  /**
+   * Returns true if the balancer should execute even if regions are in 
transition, otherwise
+   * false. This is an advanced usage feature, as it can cause more issues 
than it fixes.
+   */
+  public boolean isIgnoreRegionsInTransition() {
+    return ignoreRegionsInTransition;
+  }
+}
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceResponse.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceResponse.java
new file mode 100644
index 0000000..0d8e84b
--- /dev/null
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/BalanceResponse.java
@@ -0,0 +1,126 @@
+/*
+ *
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.client;
+
+import org.apache.yetus.audience.InterfaceAudience;
+
+/**
+ * Response returned from a balancer invocation
+ */
+@InterfaceAudience.Public
+public final class BalanceResponse {
+
+  /**
+   * Builds a {@link BalanceResponse} for returning results of a balance 
invocation to callers
+   */
+  @InterfaceAudience.Public
+  public final static class Builder {
+    private boolean balancerRan;
+    private int movesCalculated;
+    private int movesExecuted;
+
+    private Builder() {}
+
+    /**
+     * Set true if the balancer ran, otherwise false. The balancer may not run 
in some
+     * circumstances, such as if a balance is already running or there are 
regions already
+     * in transition.
+     *
+     * @param balancerRan true if balancer ran, false otherwise
+     */
+    public Builder setBalancerRan(boolean balancerRan) {
+      this.balancerRan = balancerRan;
+      return this;
+    }
+
+    /**
+     * Set how many moves were calculated by the balancer. This will be zero 
if the cluster is
+     * already balanced.
+     *
+     * @param movesCalculated moves calculated by the balance run
+     */
+    public Builder setMovesCalculated(int movesCalculated) {
+      this.movesCalculated = movesCalculated;
+      return this;
+    }
+
+    /**
+     * Set how many of the calculated moves were actually executed by the 
balancer. This should be
+     * zero if the balancer is run with {@link BalanceRequest#isDryRun()}. It 
may also not equal
+     * movesCalculated if the balancer ran out of time while executing the 
moves.
+     *
+     * @param movesExecuted moves executed by the balance run
+     */
+    public Builder setMovesExecuted(int movesExecuted) {
+      this.movesExecuted = movesExecuted;
+      return this;
+    }
+
+    /**
+     * Build the {@link BalanceResponse}
+     */
+    public BalanceResponse build() {
+      return new BalanceResponse(balancerRan, movesCalculated, movesExecuted);
+    }
+  }
+
+  /**
+   * Creates a new {@link BalanceResponse.Builder}
+   */
+  public static Builder newBuilder() {
+    return new Builder();
+  }
+
+  private final boolean balancerRan;
+  private final int movesCalculated;
+  private final int movesExecuted;
+
+  private BalanceResponse(boolean balancerRan, int movesCalculated, int 
movesExecuted) {
+    this.balancerRan = balancerRan;
+    this.movesCalculated = movesCalculated;
+    this.movesExecuted = movesExecuted;
+  }
+
+  /**
+   * Returns true if the balancer ran, otherwise false. The balancer may not 
run for a
+   * variety of reasons, such as: another balance is running, there are 
regions in
+   * transition, the cluster is in maintenance mode, etc.
+   */
+  public boolean isBalancerRan() {
+    return balancerRan;
+  }
+
+  /**
+   * The number of moves calculated by the balancer if {@link 
#isBalancerRan()} is true. This will
+   * be zero if no better balance could be found.
+   */
+  public int getMovesCalculated() {
+    return movesCalculated;
+  }
+
+  /**
+   * The number of moves actually executed by the balancer if it ran. This 
will be
+   * zero if {@link #getMovesCalculated()} is zero or if {@link 
BalanceRequest#isDryRun()}
+   * was true. It may also not be equal to {@link #getMovesCalculated()} if 
the balancer
+   * was interrupted midway through executing the moves due to max run time.
+   */
+  public int getMovesExecuted() {
+    return movesExecuted;
+  }
+}
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
index 1cbcf10..292c9cb 100644
--- 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/client/RawAsyncHBaseAdmin.java
@@ -21,7 +21,6 @@ import static org.apache.hadoop.hbase.HConstants.HIGH_QOS;
 import static org.apache.hadoop.hbase.TableName.META_TABLE_NAME;
 import static org.apache.hadoop.hbase.util.FutureUtils.addListener;
 import static 
org.apache.hadoop.hbase.util.FutureUtils.unwrapCompletionException;
-
 import edu.umd.cs.findbugs.annotations.Nullable;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -147,14 +146,13 @@ import 
org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.NameStringP
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.ProcedureDescription;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.RegionSpecifier.RegionSpecifierType;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.TableSchema;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AbortProcedureRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AbortProcedureResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AddColumnRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AddColumnResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AssignRegionRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AssignRegionResponse;
-import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.BalanceRequest;
-import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.BalanceResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.ClearDeadServersRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.ClearDeadServersResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.CreateNamespaceRequest;
@@ -3281,15 +3279,16 @@ class RawAsyncHBaseAdmin implements AsyncAdmin {
   }
 
   @Override
-  public CompletableFuture<Boolean> balance(boolean forcible) {
+  public CompletableFuture<BalanceResponse> balance(BalanceRequest request) {
     return this
-        .<Boolean> newMasterCaller()
+        .<BalanceResponse> newMasterCaller()
         .action(
-          (controller, stub) -> this.<BalanceRequest, BalanceResponse, 
Boolean> call(controller,
-            stub, RequestConverter.buildBalanceRequest(forcible),
-            (s, c, req, done) -> s.balance(c, req, done), (resp) -> 
resp.getBalancerRan())).call();
+          (controller, stub) -> this.<MasterProtos.BalanceRequest, 
MasterProtos.BalanceResponse, BalanceResponse> call(controller,
+            stub, ProtobufUtil.toBalanceRequest(request),
+            (s, c, req, done) -> s.balance(c, req, done), (resp) -> 
ProtobufUtil.toBalanceResponse(resp))).call();
   }
 
+
   @Override
   public CompletableFuture<Boolean> isBalancerEnabled() {
     return this
@@ -3999,13 +3998,13 @@ class RawAsyncHBaseAdmin implements AsyncAdmin {
   }
 
   @Override
-  public CompletableFuture<Boolean> balanceRSGroup(String groupName) {
-    return this.<Boolean> newMasterCaller()
-        .action((controller, stub) -> this.
-            <BalanceRSGroupRequest, BalanceRSGroupResponse, Boolean> 
call(controller, stub,
-                
BalanceRSGroupRequest.newBuilder().setRSGroupName(groupName).build(),
-              (s, c, req, done) -> s.balanceRSGroup(c, req, done), resp -> 
resp.getBalanceRan()))
-        .call();
+  public CompletableFuture<BalanceResponse> balanceRSGroup(String groupName,
+    BalanceRequest request) {
+    return this.<BalanceResponse>newMasterCaller().action(
+        (controller, stub) -> this.<BalanceRSGroupRequest, 
BalanceRSGroupResponse, BalanceResponse>call(
+          controller, stub, 
ProtobufUtil.createBalanceRSGroupRequest(groupName, request),
+          MasterService.Interface::balanceRSGroup, 
ProtobufUtil::toBalanceResponse))
+      .call();
   }
 
   @Override
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
index 329894c..82da13e 100644
--- 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/ProtobufUtil.java
@@ -47,6 +47,7 @@ import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.ByteBufferExtendedCell;
 import org.apache.hadoop.hbase.CacheEvictionStats;
 import org.apache.hadoop.hbase.CacheEvictionStatsBuilder;
@@ -68,6 +69,7 @@ import org.apache.hadoop.hbase.NamespaceDescriptor;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.Append;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.BalancerRejection;
 import org.apache.hadoop.hbase.client.BalancerDecision;
 import org.apache.hadoop.hbase.client.CheckAndMutate;
@@ -118,6 +120,7 @@ import 
org.apache.hadoop.hbase.replication.ReplicationLoadSource;
 import org.apache.hadoop.hbase.rsgroup.RSGroupInfo;
 import org.apache.hadoop.hbase.security.visibility.Authorizations;
 import org.apache.hadoop.hbase.security.visibility.CellVisibility;
+import org.apache.hadoop.hbase.shaded.protobuf.generated.RSGroupAdminProtos;
 import org.apache.hadoop.hbase.util.Addressing;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.DynamicClassLoader;
@@ -3607,6 +3610,36 @@ public final class ProtobufUtil {
     return clearSlowLogResponses.getIsCleaned();
   }
 
+  public static void 
populateBalanceRSGroupResponse(RSGroupAdminProtos.BalanceRSGroupResponse.Builder
 responseBuilder, BalanceResponse response) {
+    responseBuilder
+      .setBalanceRan(response.isBalancerRan())
+      .setMovesCalculated(response.getMovesCalculated())
+      .setMovesExecuted(response.getMovesExecuted());
+  }
+
+  public static BalanceResponse 
toBalanceResponse(RSGroupAdminProtos.BalanceRSGroupResponse response) {
+    return BalanceResponse.newBuilder()
+      .setBalancerRan(response.getBalanceRan())
+      .setMovesExecuted(response.hasMovesExecuted() ? 
response.getMovesExecuted() : 0)
+      .setMovesCalculated(response.hasMovesCalculated() ? 
response.getMovesCalculated() : 0)
+      .build();
+  }
+
+  public static RSGroupAdminProtos.BalanceRSGroupRequest 
createBalanceRSGroupRequest(String groupName, BalanceRequest request) {
+    return RSGroupAdminProtos.BalanceRSGroupRequest.newBuilder()
+      .setRSGroupName(groupName)
+      .setDryRun(request.isDryRun())
+      .setIgnoreRit(request.isIgnoreRegionsInTransition())
+      .build();
+  }
+
+  public static BalanceRequest 
toBalanceRequest(RSGroupAdminProtos.BalanceRSGroupRequest request) {
+    return BalanceRequest.newBuilder()
+      .setDryRun(request.hasDryRun() && request.getDryRun())
+      .setIgnoreRegionsInTransition(request.hasIgnoreRit() && 
request.getIgnoreRit())
+      .build();
+  }
+
   public static RSGroupInfo toGroupInfo(RSGroupProtos.RSGroupInfo proto) {
     RSGroupInfo rsGroupInfo = new RSGroupInfo(proto.getName());
 
@@ -3835,4 +3868,34 @@ public final class ProtobufUtil {
       .build();
   }
 
+  public static MasterProtos.BalanceRequest toBalanceRequest(BalanceRequest 
request) {
+    return MasterProtos.BalanceRequest.newBuilder()
+      .setDryRun(request.isDryRun())
+      .setIgnoreRit(request.isIgnoreRegionsInTransition())
+      .build();
+  }
+
+  public static BalanceRequest toBalanceRequest(MasterProtos.BalanceRequest 
request) {
+    return BalanceRequest.newBuilder()
+      .setDryRun(request.hasDryRun() && request.getDryRun())
+      .setIgnoreRegionsInTransition(request.hasIgnoreRit() && 
request.getIgnoreRit())
+      .build();
+  }
+
+  public static MasterProtos.BalanceResponse toBalanceResponse(BalanceResponse 
response) {
+    return MasterProtos.BalanceResponse.newBuilder()
+      .setBalancerRan(response.isBalancerRan())
+      .setMovesCalculated(response.getMovesCalculated())
+      .setMovesExecuted(response.getMovesExecuted())
+      .build();
+  }
+
+  public static BalanceResponse toBalanceResponse(MasterProtos.BalanceResponse 
response) {
+    return BalanceResponse.newBuilder()
+      .setBalancerRan(response.hasBalancerRan() && response.getBalancerRan())
+      .setMovesCalculated(response.hasMovesCalculated() ? 
response.getMovesExecuted() : 0)
+      .setMovesExecuted(response.hasMovesExecuted() ? 
response.getMovesExecuted() : 0)
+      .build();
+  }
+
 }
diff --git 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
index c5911ab..821f731 100644
--- 
a/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
+++ 
b/hbase-client/src/main/java/org/apache/hadoop/hbase/shaded/protobuf/RequestConverter.java
@@ -105,7 +105,6 @@ import 
org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos.RegionSpeci
 import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AddColumnRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AssignRegionRequest;
-import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.BalanceRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.ClearDeadServersRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.CreateNamespaceRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.CreateTableRequest;
@@ -1327,15 +1326,6 @@ public final class RequestConverter {
   }
 
   /**
-   * Creates a protocol buffer BalanceRequest
-   *
-   * @return a BalanceRequest
-   */
-  public static BalanceRequest buildBalanceRequest(boolean force) {
-    return BalanceRequest.newBuilder().setForce(force).build();
-  }
-
-  /**
    * Creates a protocol buffer SetBalancerRunningRequest
    *
    * @param on
diff --git a/hbase-protocol-shaded/src/main/protobuf/server/master/Master.proto 
b/hbase-protocol-shaded/src/main/protobuf/server/master/Master.proto
index 628b0ca..ea09e11 100644
--- a/hbase-protocol-shaded/src/main/protobuf/server/master/Master.proto
+++ b/hbase-protocol-shaded/src/main/protobuf/server/master/Master.proto
@@ -293,11 +293,14 @@ message IsInMaintenanceModeResponse {
 }
 
 message BalanceRequest {
-  optional bool force = 1;
+  optional bool ignore_rit = 1;
+  optional bool dry_run = 2;
 }
 
 message BalanceResponse {
   required bool balancer_ran = 1;
+  optional uint32 moves_calculated = 2;
+  optional uint32 moves_executed = 3;
 }
 
 message SetBalancerRunningRequest {
diff --git 
a/hbase-protocol-shaded/src/main/protobuf/server/rsgroup/RSGroupAdmin.proto 
b/hbase-protocol-shaded/src/main/protobuf/server/rsgroup/RSGroupAdmin.proto
index 9f38d2b..7f6ba4d 100644
--- a/hbase-protocol-shaded/src/main/protobuf/server/rsgroup/RSGroupAdmin.proto
+++ b/hbase-protocol-shaded/src/main/protobuf/server/rsgroup/RSGroupAdmin.proto
@@ -85,10 +85,14 @@ message RemoveRSGroupResponse {
 
 message BalanceRSGroupRequest {
   required string r_s_group_name = 1;
+  optional bool ignore_rit = 2;
+  optional bool dry_run = 3;
 }
 
 message BalanceRSGroupResponse {
   required bool balanceRan = 1;
+  optional uint32 moves_calculated = 2;
+  optional uint32 moves_executed = 3;
 }
 
 message ListRSGroupInfosRequest {
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java
index ac35caa..02607b7 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/coprocessor/MasterObserver.java
@@ -28,6 +28,8 @@ import org.apache.hadoop.hbase.MetaMutationAnnotation;
 import org.apache.hadoop.hbase.NamespaceDescriptor;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.MasterSwitchType;
 import org.apache.hadoop.hbase.client.Mutation;
 import org.apache.hadoop.hbase.client.RegionInfo;
@@ -540,18 +542,20 @@ public interface MasterObserver {
    * Called prior to requesting rebalancing of the cluster regions, though 
after
    * the initial checks for regions in transition and the balance switch flag.
    * @param ctx the environment to interact with the framework and master
+   * @param request the request used to trigger the balancer
    */
-  default void preBalance(final ObserverContext<MasterCoprocessorEnvironment> 
ctx)
+  default void preBalance(final ObserverContext<MasterCoprocessorEnvironment> 
ctx, BalanceRequest request)
       throws IOException {}
 
   /**
    * Called after the balancing plan has been submitted.
    * @param ctx the environment to interact with the framework and master
+   * @param request the request used to trigger the balance
    * @param plans the RegionPlans which master has executed. RegionPlan serves 
as hint
    * as for the final destination for the underlying region but may not 
represent the
    * final state of assignment
    */
-  default void postBalance(final ObserverContext<MasterCoprocessorEnvironment> 
ctx, List<RegionPlan> plans)
+  default void postBalance(final ObserverContext<MasterCoprocessorEnvironment> 
ctx, BalanceRequest request, List<RegionPlan> plans)
       throws IOException {}
 
   /**
@@ -1249,15 +1253,19 @@ public interface MasterObserver {
    * @param groupName group name
    */
   default void preBalanceRSGroup(final 
ObserverContext<MasterCoprocessorEnvironment> ctx,
-                         String groupName) throws IOException {}
+      String groupName, BalanceRequest request) throws IOException {
+  }
 
   /**
    * Called after a region server group is removed
    * @param ctx the environment to interact with the framework and master
    * @param groupName group name
+   * @param request the request sent to the balancer
+   * @param response the response returned by the balancer
    */
   default void postBalanceRSGroup(final 
ObserverContext<MasterCoprocessorEnvironment> ctx,
-                          String groupName, boolean balancerRan) throws 
IOException {}
+      String groupName, BalanceRequest request, BalanceResponse response) 
throws IOException {
+  }
 
   /**
    * Called before servers are removed from rsgroup
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
index 0bf160b..2815809 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/HMaster.java
@@ -60,6 +60,7 @@ import org.apache.hadoop.hbase.CatalogFamilyFormat;
 import org.apache.hadoop.hbase.Cell;
 import org.apache.hadoop.hbase.CellBuilderFactory;
 import org.apache.hadoop.hbase.CellBuilderType;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.ClusterId;
 import org.apache.hadoop.hbase.ClusterMetrics;
 import org.apache.hadoop.hbase.ClusterMetrics.Option;
@@ -82,6 +83,7 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotDisabledException;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.UnknownRegionException;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
 import org.apache.hadoop.hbase.client.CompactionState;
 import org.apache.hadoop.hbase.client.MasterSwitchType;
@@ -1771,8 +1773,8 @@ public class HMaster extends HRegionServer implements 
MasterServices {
     if (interrupted) Thread.currentThread().interrupt();
   }
 
-  public boolean balance() throws IOException {
-    return balance(false);
+  public BalanceResponse balance() throws IOException {
+    return balance(BalanceRequest.defaultInstance());
   }
 
   /**
@@ -1798,12 +1800,16 @@ public class HMaster extends HRegionServer implements 
MasterServices {
     return false;
   }
 
-  public boolean balance(boolean force) throws IOException {
-    if (loadBalancerTracker == null || !loadBalancerTracker.isBalancerOn()) {
-      return false;
+  public BalanceResponse balance(BalanceRequest request) throws IOException {
+    BalanceResponse.Builder responseBuilder = BalanceResponse.newBuilder();
+
+    if (loadBalancerTracker == null
+      || !(loadBalancerTracker.isBalancerOn() || request.isDryRun())) {
+      return responseBuilder.build();
     }
+
     if (skipRegionManagementAction("balancer")) {
-      return false;
+      return responseBuilder.build();
     }
 
     synchronized (this.balancer) {
@@ -1820,28 +1826,29 @@ public class HMaster extends HRegionServer implements 
MasterServices {
           toPrint = regionsInTransition.subList(0, max);
           truncated = true;
         }
-        if (!force || metaInTransition) {
-          LOG.info("Not running balancer (force=" + force + ", metaRIT=" + 
metaInTransition +
-            ") because " + regionsInTransition.size() + " region(s) in 
transition: " + toPrint +
-            (truncated? "(truncated list)": ""));
-          return false;
+
+        if (!request.isIgnoreRegionsInTransition() || metaInTransition) {
+          LOG.info("Not running balancer (ignoreRIT=false" + ", metaRIT=" + 
metaInTransition +
+            ") because " + regionsInTransition.size() + " region(s) in 
transition: " + toPrint
+            + (truncated? "(truncated list)": ""));
+          return responseBuilder.build();
         }
       }
       if (this.serverManager.areDeadServersInProgress()) {
         LOG.info("Not running balancer because processing dead 
regionserver(s): " +
           this.serverManager.getDeadServers());
-        return false;
+        return responseBuilder.build();
       }
 
       if (this.cpHost != null) {
         try {
-          if (this.cpHost.preBalance()) {
+          if (this.cpHost.preBalance(request)) {
             LOG.debug("Coprocessor bypassing balancer request");
-            return false;
+            return responseBuilder.build();
           }
         } catch (IOException ioe) {
           LOG.error("Error invoking master coprocessor preBalance()", ioe);
-          return false;
+          return responseBuilder.build();
         }
       }
 
@@ -1857,25 +1864,34 @@ public class HMaster extends HRegionServer implements 
MasterServices {
 
       List<RegionPlan> plans = this.balancer.balanceCluster(assignments);
 
+      responseBuilder.setBalancerRan(true).setMovesCalculated(plans == null ? 
0 : plans.size());
+
       if (skipRegionManagementAction("balancer")) {
         // make one last check that the cluster isn't shutting down before 
proceeding.
-        return false;
+        return responseBuilder.build();
       }
 
-      List<RegionPlan> sucRPs = executeRegionPlansWithThrottling(plans);
+      // For dry run we don't actually want to execute the moves, but we do 
want
+      // to execute the coprocessor below
+      List<RegionPlan> sucRPs = request.isDryRun()
+        ? Collections.emptyList()
+        : executeRegionPlansWithThrottling(plans);
 
       if (this.cpHost != null) {
         try {
-          this.cpHost.postBalance(sucRPs);
+          this.cpHost.postBalance(request, sucRPs);
         } catch (IOException ioe) {
           // balancing already succeeded so don't change the result
           LOG.error("Error invoking master coprocessor postBalance()", ioe);
         }
       }
+
+      responseBuilder.setMovesExecuted(sucRPs.size());
     }
+
     // If LoadBalancer did not generate any plans, it means the cluster is 
already balanced.
     // Return true indicating a success.
-    return true;
+    return responseBuilder.build();
   }
 
   /**
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java
index 01d1a62..3c1fcec 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterCoprocessorHost.java
@@ -29,6 +29,8 @@ import org.apache.hadoop.hbase.MetaMutationAnnotation;
 import org.apache.hadoop.hbase.NamespaceDescriptor;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.MasterSwitchType;
 import org.apache.hadoop.hbase.client.Mutation;
@@ -732,20 +734,20 @@ public class MasterCoprocessorHost
     });
   }
 
-  public boolean preBalance() throws IOException {
+  public boolean preBalance(final BalanceRequest request) throws IOException {
     return execOperation(coprocEnvironments.isEmpty() ? null : new 
MasterObserverOperation() {
       @Override
       public void call(MasterObserver observer) throws IOException {
-        observer.preBalance(this);
+        observer.preBalance(this, request);
       }
     });
   }
 
-  public void postBalance(final List<RegionPlan> plans) throws IOException {
+  public void postBalance(final BalanceRequest request, final List<RegionPlan> 
plans) throws IOException {
     execOperation(coprocEnvironments.isEmpty() ? null : new 
MasterObserverOperation() {
       @Override
       public void call(MasterObserver observer) throws IOException {
-        observer.postBalance(this, plans);
+        observer.postBalance(this, request, plans);
       }
     });
   }
@@ -1428,22 +1430,22 @@ public class MasterCoprocessorHost
     });
   }
 
-  public void preBalanceRSGroup(final String name)
+  public void preBalanceRSGroup(final String name, final BalanceRequest 
request)
       throws IOException {
     execOperation(coprocEnvironments.isEmpty() ? null : new 
MasterObserverOperation() {
       @Override
       public void call(MasterObserver observer) throws IOException {
-        observer.preBalanceRSGroup(this, name);
+        observer.preBalanceRSGroup(this, name, request);
       }
     });
   }
 
-  public void postBalanceRSGroup(final String name, final boolean balanceRan)
+  public void postBalanceRSGroup(final String name, final BalanceRequest 
request, final BalanceResponse response)
       throws IOException {
     execOperation(coprocEnvironments.isEmpty() ? null : new 
MasterObserverOperation() {
       @Override
       public void call(MasterObserver observer) throws IOException {
-        observer.postBalanceRSGroup(this, name, balanceRan);
+        observer.postBalanceRSGroup(this, name, request, response);
       }
     });
   }
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
index 2a26fa0..a8446c3 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/master/MasterRpcServices.java
@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.master;
 
 import static org.apache.hadoop.hbase.master.MasterWalManager.META_FILTER;
-
 import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.lang.reflect.InvocationTargetException;
@@ -48,6 +47,8 @@ import org.apache.hadoop.hbase.ServerMetricsBuilder;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.UnknownRegionException;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.MasterSwitchType;
 import org.apache.hadoop.hbase.client.NormalizeTableFilterParams;
 import org.apache.hadoop.hbase.client.Put;
@@ -127,7 +128,6 @@ import org.apache.yetus.audience.InterfaceAudience;
 import org.apache.zookeeper.KeeperException;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
 import org.apache.hbase.thirdparty.com.google.protobuf.ByteString;
 import 
org.apache.hbase.thirdparty.com.google.protobuf.Descriptors.MethodDescriptor;
@@ -137,7 +137,6 @@ import 
org.apache.hbase.thirdparty.com.google.protobuf.RpcController;
 import org.apache.hbase.thirdparty.com.google.protobuf.Service;
 import org.apache.hbase.thirdparty.com.google.protobuf.ServiceException;
 import org.apache.hbase.thirdparty.com.google.protobuf.UnsafeByteOperations;
-
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.ResponseConverter;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.AccessControlProtos;
@@ -176,8 +175,6 @@ import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AddColumnR
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AddColumnResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AssignRegionRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.AssignRegionResponse;
-import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.BalanceRequest;
-import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.BalanceResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.ClearDeadServersRequest;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.ClearDeadServersResponse;
 import 
org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProtos.CreateNamespaceRequest;
@@ -696,11 +693,10 @@ public class MasterRpcServices extends RSRpcServices 
implements
 
 
   @Override
-  public BalanceResponse balance(RpcController controller,
-      BalanceRequest request) throws ServiceException {
+  public MasterProtos.BalanceResponse balance(RpcController controller,
+      MasterProtos.BalanceRequest request) throws ServiceException {
     try {
-      return BalanceResponse.newBuilder().setBalancerRan(master.balance(
-        request.hasForce()? request.getForce(): false)).build();
+      return 
ProtobufUtil.toBalanceResponse(master.balance(ProtobufUtil.toBalanceRequest(request)));
     } catch (IOException ex) {
       throw new ServiceException(ex);
     }
@@ -3141,18 +3137,24 @@ public class MasterRpcServices extends RSRpcServices 
implements
   @Override
   public BalanceRSGroupResponse balanceRSGroup(RpcController controller,
       BalanceRSGroupRequest request) throws ServiceException {
-    BalanceRSGroupResponse.Builder builder = 
BalanceRSGroupResponse.newBuilder();
+    BalanceRequest balanceRequest = ProtobufUtil.toBalanceRequest(request);
+
+    BalanceRSGroupResponse.Builder builder = 
BalanceRSGroupResponse.newBuilder()
+      .setBalanceRan(false);
+
     LOG.info(
-        master.getClientIdAuditPrefix() + " balance rsgroup, group=" + 
request.getRSGroupName());
+      master.getClientIdAuditPrefix() + " balance rsgroup, group=" + 
request.getRSGroupName());
     try {
       if (master.getMasterCoprocessorHost() != null) {
-        
master.getMasterCoprocessorHost().preBalanceRSGroup(request.getRSGroupName());
+        master.getMasterCoprocessorHost()
+          .preBalanceRSGroup(request.getRSGroupName(), balanceRequest);
       }
-      boolean balancerRan =
-          
master.getRSGroupInfoManager().balanceRSGroup(request.getRSGroupName());
-      builder.setBalanceRan(balancerRan);
+      BalanceResponse response =
+        
master.getRSGroupInfoManager().balanceRSGroup(request.getRSGroupName(), 
balanceRequest);
+      ProtobufUtil.populateBalanceRSGroupResponse(builder, response);
       if (master.getMasterCoprocessorHost() != null) {
-        
master.getMasterCoprocessorHost().postBalanceRSGroup(request.getRSGroupName(), 
balancerRan);
+        master.getMasterCoprocessorHost()
+          .postBalanceRSGroup(request.getRSGroupName(), balanceRequest, 
response);
       }
     } catch (IOException e) {
       throw new ServiceException(e);
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/DisabledRSGroupInfoManager.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/DisabledRSGroupInfoManager.java
index 3323acd..8ed2505 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/DisabledRSGroupInfoManager.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/DisabledRSGroupInfoManager.java
@@ -27,6 +27,8 @@ import java.util.TreeSet;
 import org.apache.hadoop.hbase.DoNotRetryIOException;
 import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.master.ServerManager;
 import org.apache.hadoop.hbase.net.Address;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -108,7 +110,7 @@ class DisabledRSGroupInfoManager implements 
RSGroupInfoManager {
   }
 
   @Override
-  public boolean balanceRSGroup(String groupName) throws IOException {
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) throws IOException {
     throw new DoNotRetryIOException("RSGroup is disabled");
   }
 
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminClient.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminClient.java
index 0fe42f3..4c29154 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminClient.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminClient.java
@@ -24,6 +24,8 @@ import java.util.Set;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.net.Address;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -161,13 +163,12 @@ public class RSGroupAdminClient {
 
   /**
    * Balance regions in the given RegionServer group.
-   * @return boolean Whether balance ran or not
+   * @return BalanceResponse details about the balancer run
    */
-  public boolean balanceRSGroup(String groupName) throws IOException {
-    BalanceRSGroupRequest request =
-      BalanceRSGroupRequest.newBuilder().setRSGroupName(groupName).build();
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) throws IOException {
     try {
-      return stub.balanceRSGroup(null, request).getBalanceRan();
+      BalanceRSGroupRequest req = 
ProtobufUtil.createBalanceRSGroupRequest(groupName, request);
+      return ProtobufUtil.toBalanceResponse(stub.balanceRSGroup(null, req));
     } catch (ServiceException e) {
       throw ProtobufUtil.handleRemoteException(e);
     }
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminServiceImpl.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminServiceImpl.java
index 241fd65..b8b2a4f 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminServiceImpl.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupAdminServiceImpl.java
@@ -28,6 +28,8 @@ import java.util.Set;
 import java.util.stream.Collectors;
 import org.apache.hadoop.hbase.HConstants;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
 import org.apache.hadoop.hbase.ipc.CoprocessorRpcUtils;
@@ -37,11 +39,9 @@ import org.apache.hadoop.hbase.net.Address;
 import org.apache.hadoop.hbase.procedure2.Procedure;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.apache.hbase.thirdparty.com.google.common.collect.Sets;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcCallback;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcController;
-
 import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.RSGroupAdminProtos;
@@ -265,21 +265,28 @@ class RSGroupAdminServiceImpl extends 
RSGroupAdminProtos.RSGroupAdminService {
   @Override
   public void balanceRSGroup(RpcController controller, BalanceRSGroupRequest 
request,
       RpcCallback<BalanceRSGroupResponse> done) {
-    BalanceRSGroupResponse.Builder builder = 
BalanceRSGroupResponse.newBuilder();
+    BalanceRequest balanceRequest = ProtobufUtil.toBalanceRequest(request);
+    BalanceRSGroupResponse.Builder builder = 
BalanceRSGroupResponse.newBuilder()
+      .setBalanceRan(false);
+
     LOG.info(
       master.getClientIdAuditPrefix() + " balance rsgroup, group=" + 
request.getRSGroupName());
     try {
       if (master.getMasterCoprocessorHost() != null) {
-        
master.getMasterCoprocessorHost().preBalanceRSGroup(request.getRSGroupName());
+        master.getMasterCoprocessorHost()
+          .preBalanceRSGroup(request.getRSGroupName(), balanceRequest);
       }
-      boolean balancerRan = 
rsGroupInfoManager.balanceRSGroup(request.getRSGroupName());
-      builder.setBalanceRan(balancerRan);
+
+      BalanceResponse response =
+        rsGroupInfoManager.balanceRSGroup(request.getRSGroupName(), 
balanceRequest);
+      ProtobufUtil.populateBalanceRSGroupResponse(builder, response);
+
       if (master.getMasterCoprocessorHost() != null) {
-        
master.getMasterCoprocessorHost().postBalanceRSGroup(request.getRSGroupName(), 
balancerRan);
+        master.getMasterCoprocessorHost()
+          .postBalanceRSGroup(request.getRSGroupName(), balanceRequest, 
response);
       }
     } catch (IOException e) {
       CoprocessorRpcUtils.setControllerException(controller, e);
-      builder.setBalanceRan(false);
     }
     done.run(builder.build());
   }
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManager.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManager.java
index 350f2b4..9d73a52 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManager.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManager.java
@@ -22,6 +22,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.master.MasterServices;
 import org.apache.hadoop.hbase.net.Address;
 import org.apache.yetus.audience.InterfaceAudience;
@@ -93,7 +95,7 @@ public interface RSGroupInfoManager {
   /**
    * Balance a region server group.
    */
-  boolean balanceRSGroup(String groupName) throws IOException;
+  BalanceResponse balanceRSGroup(String groupName, BalanceRequest request) 
throws IOException;
 
   /**
    * Set group for tables.
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManagerImpl.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManagerImpl.java
index 3ef9365..03a31e3 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManagerImpl.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/rsgroup/RSGroupInfoManagerImpl.java
@@ -46,6 +46,8 @@ import org.apache.hadoop.hbase.TableDescriptors;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.AsyncClusterConnection;
 import org.apache.hadoop.hbase.client.AsyncTable;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.CoprocessorDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Delete;
@@ -1146,29 +1148,33 @@ final class RSGroupInfoManagerImpl implements 
RSGroupInfoManager {
   }
 
   @Override
-  public boolean balanceRSGroup(String groupName) throws IOException {
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) throws IOException {
     ServerManager serverManager = masterServices.getServerManager();
     LoadBalancer balancer = masterServices.getLoadBalancer();
     getRSGroupInfo(groupName);
 
+    BalanceResponse.Builder responseBuilder = BalanceResponse.newBuilder();
+
     synchronized (balancer) {
       // If balance not true, don't run balancer.
-      if (!masterServices.isBalancerOn()) {
-        return false;
+      if (!masterServices.isBalancerOn() && !request.isDryRun()) {
+        return responseBuilder.build();
       }
+
       // Only allow one balance run at at time.
       Map<String, RegionState> groupRIT = 
rsGroupGetRegionsInTransition(groupName);
-      if (groupRIT.size() > 0) {
+      if (groupRIT.size() > 0 && !request.isIgnoreRegionsInTransition()) {
         LOG.debug("Not running balancer because {} region(s) in transition: 
{}", groupRIT.size(),
             
StringUtils.abbreviate(masterServices.getAssignmentManager().getRegionStates()
                     .getRegionsInTransition().toString(),
                 256));
-        return false;
+        return responseBuilder.build();
       }
+
       if (serverManager.areDeadServersInProgress()) {
         LOG.debug("Not running balancer because processing dead 
regionserver(s): {}",
             serverManager.getDeadServers());
-        return false;
+        return responseBuilder.build();
       }
 
       // We balance per group instead of per table
@@ -1176,12 +1182,17 @@ final class RSGroupInfoManagerImpl implements 
RSGroupInfoManager {
           getRSGroupAssignmentsByTable(masterServices.getTableStateManager(), 
groupName);
       List<RegionPlan> plans = balancer.balanceCluster(assignmentsByTable);
       boolean balancerRan = !plans.isEmpty();
-      if (balancerRan) {
+
+      
responseBuilder.setBalancerRan(balancerRan).setMovesCalculated(plans.size());
+
+      if (balancerRan && !request.isDryRun()) {
         LOG.info("RSGroup balance {} starting with plan count: {}", groupName, 
plans.size());
-        masterServices.executeRegionPlansWithThrottling(plans);
+        List<RegionPlan> executed = 
masterServices.executeRegionPlansWithThrottling(plans);
+        responseBuilder.setMovesExecuted(executed.size());
         LOG.info("RSGroup balance " + groupName + " completed");
       }
-      return balancerRan;
+
+      return responseBuilder.build();
     }
   }
 
diff --git 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessController.java
 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessController.java
index ec5a1b8..5ed12c4 100644
--- 
a/hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessController.java
+++ 
b/hbase-server/src/main/java/org/apache/hadoop/hbase/security/access/AccessController.java
@@ -53,6 +53,7 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.Tag;
 import org.apache.hadoop.hbase.client.Admin;
 import org.apache.hadoop.hbase.client.Append;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Delete;
@@ -1000,7 +1001,7 @@ public class AccessController implements 
MasterCoprocessor, RegionCoprocessor,
   }
 
   @Override
-  public void preBalance(ObserverContext<MasterCoprocessorEnvironment> c)
+  public void preBalance(ObserverContext<MasterCoprocessorEnvironment> c, 
BalanceRequest request)
       throws IOException {
     requirePermission(c, "balance", Action.ADMIN);
   }
@@ -2554,7 +2555,7 @@ public class AccessController implements 
MasterCoprocessor, RegionCoprocessor,
 
   @Override
   public void preBalanceRSGroup(ObserverContext<MasterCoprocessorEnvironment> 
ctx,
-      String groupName) throws IOException {
+      String groupName, BalanceRequest request) throws IOException {
     accessChecker.requirePermission(getActiveUser(ctx), "balanceRSGroup",
         null, Permission.Action.ADMIN);
   }
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/TestRegionRebalancing.java 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/TestRegionRebalancing.java
index c9ac60d..4f23bc0 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/TestRegionRebalancing.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/TestRegionRebalancing.java
@@ -18,6 +18,7 @@
 package org.apache.hadoop.hbase;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
 
 import java.io.IOException;
@@ -27,6 +28,7 @@ import java.util.Arrays;
 import java.util.Collection;
 import java.util.List;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
@@ -132,14 +134,21 @@ public class TestRegionRebalancing {
       assertRegionsAreBalanced();
 
       // On a balanced cluster, calling balance() should return true
-      assert(UTIL.getHBaseCluster().getMaster().balance() == true);
+      BalanceResponse response = UTIL.getHBaseCluster().getMaster().balance();
+      assertTrue(response.isBalancerRan());
+      assertEquals(0, response.getMovesCalculated());
+      assertEquals(0, response.getMovesExecuted());
 
       // if we add a server, then the balance() call should return true
       // add a region server - total of 3
       LOG.info("Started third server=" +
           
UTIL.getHBaseCluster().startRegionServer().getRegionServer().getServerName());
       waitForAllRegionsAssigned();
-      assert(UTIL.getHBaseCluster().getMaster().balance() == true);
+
+      response = UTIL.getHBaseCluster().getMaster().balance();
+      assertTrue(response.isBalancerRan());
+      assertTrue(response.getMovesCalculated() > 0);
+      assertEquals(response.getMovesCalculated(), response.getMovesExecuted());
       assertRegionsAreBalanced();
 
       // kill a region server - total of 2
@@ -156,14 +165,24 @@ public class TestRegionRebalancing {
           
UTIL.getHBaseCluster().startRegionServer().getRegionServer().getServerName());
       waitOnCrashProcessing();
       waitForAllRegionsAssigned();
-      assert(UTIL.getHBaseCluster().getMaster().balance() == true);
+
+      response = UTIL.getHBaseCluster().getMaster().balance();
+      assertTrue(response.isBalancerRan());
+      assertTrue(response.getMovesCalculated() > 0);
+      assertEquals(response.getMovesCalculated(), response.getMovesExecuted());
+
       assertRegionsAreBalanced();
       for (int i = 0; i < 6; i++){
         LOG.info("Adding " + (i + 5) + "th region server");
         UTIL.getHBaseCluster().startRegionServer();
       }
       waitForAllRegionsAssigned();
-      assert(UTIL.getHBaseCluster().getMaster().balance() == true);
+
+      response = UTIL.getHBaseCluster().getMaster().balance();
+      assertTrue(response.isBalancerRan());
+      assertTrue(response.getMovesCalculated() > 0);
+      assertEquals(response.getMovesCalculated(), response.getMovesExecuted());
+
       assertRegionsAreBalanced();
       regionLocator.close();
     }
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableGetMultiThreaded.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableGetMultiThreaded.java
index ca11ea6..107d59e 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableGetMultiThreaded.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestAsyncTableGetMultiThreaded.java
@@ -196,7 +196,7 @@ public class TestAsyncTableGetMultiThreaded {
       }
       Thread.sleep(5000);
       LOG.info("====== Balancing cluster ======");
-      admin.balance(true);
+      
admin.balance(BalanceRequest.newBuilder().setIgnoreRegionsInTransition(true).build());
       LOG.info("====== Balance cluster done ======");
       Thread.sleep(5000);
       ServerName metaServer = 
TEST_UTIL.getHBaseCluster().getServerHoldingMeta();
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMultiParallel.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMultiParallel.java
index 038635b..bb878ca 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMultiParallel.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMultiParallel.java
@@ -679,7 +679,7 @@ public class TestMultiParallel {
 
     @Override
     public void postBalance(final 
ObserverContext<MasterCoprocessorEnvironment> ctx,
-        List<RegionPlan> plans) throws IOException {
+        BalanceRequest request, List<RegionPlan> plans) throws IOException {
       if (!plans.isEmpty()) {
         postBalanceCount.incrementAndGet();
       }
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestSeparateClientZKCluster.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestSeparateClientZKCluster.java
index 24a9c51..5274813 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestSeparateClientZKCluster.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestSeparateClientZKCluster.java
@@ -144,7 +144,7 @@ public class TestSeparateClientZKCluster {
       }
       LOG.info("Got master {}", cluster.getMaster().getServerName());
       // confirm client access still works
-      assertTrue(admin.balance(false));
+      
assertTrue(admin.balance(BalanceRequest.defaultInstance()).isBalancerRan());
     }
   }
 
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java
index c60c55f..8efc4dc 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/coprocessor/TestMasterObserver.java
@@ -38,6 +38,8 @@ import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.SingleProcessHBaseCluster;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
@@ -690,13 +692,14 @@ public class TestMasterObserver {
     }
 
     @Override
-    public void preBalance(ObserverContext<MasterCoprocessorEnvironment> env)
-        throws IOException {
+    public void preBalance(ObserverContext<MasterCoprocessorEnvironment> env,
+      BalanceRequest request) throws IOException {
       preBalanceCalled = true;
     }
 
     @Override
     public void postBalance(ObserverContext<MasterCoprocessorEnvironment> env,
+        BalanceRequest request,
         List<RegionPlan> plans) throws IOException {
       postBalanceCalled = true;
     }
@@ -1162,12 +1165,12 @@ public class TestMasterObserver {
 
     @Override
     public void 
preBalanceRSGroup(ObserverContext<MasterCoprocessorEnvironment> ctx,
-                                  String groupName) throws IOException {
+                                  String groupName, BalanceRequest request) 
throws IOException {
     }
 
     @Override
     public void 
postBalanceRSGroup(ObserverContext<MasterCoprocessorEnvironment> ctx,
-        String groupName, boolean balancerRan) throws IOException {
+        String groupName, BalanceRequest request, BalanceResponse response) 
throws IOException {
     }
 
     @Override
@@ -1621,7 +1624,7 @@ public class TestMasterObserver {
       UTIL.waitUntilNoRegionsInTransition();
       // now trigger a balance
       master.balanceSwitch(true);
-      boolean balanceRun = master.balance();
+      master.balance();
       assertTrue("Coprocessor should be called on region rebalancing",
           cp.wasBalanceCalled());
     } finally {
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterDryRunBalancer.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterDryRunBalancer.java
new file mode 100644
index 0000000..5b41e0a
--- /dev/null
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/TestMasterDryRunBalancer.java
@@ -0,0 +1,125 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hbase.master;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import java.io.IOException;
+import org.apache.hadoop.hbase.HBaseClassTestRule;
+import org.apache.hadoop.hbase.HBaseTestingUtil;
+import org.apache.hadoop.hbase.ServerName;
+import org.apache.hadoop.hbase.TableName;
+import org.apache.hadoop.hbase.Waiter;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
+import org.apache.hadoop.hbase.client.RegionInfo;
+import org.apache.hadoop.hbase.regionserver.HRegionServer;
+import org.apache.hadoop.hbase.testclassification.MasterTests;
+import org.apache.hadoop.hbase.testclassification.MediumTests;
+import org.apache.hadoop.hbase.util.Bytes;
+import org.junit.After;
+import org.junit.ClassRule;
+import org.junit.Test;
+import org.junit.experimental.categories.Category;
+import org.mockito.Mockito;
+
+@Category({ MasterTests.class, MediumTests.class})
+public class TestMasterDryRunBalancer {
+  @ClassRule
+  public static final HBaseClassTestRule CLASS_RULE =
+    HBaseClassTestRule.forClass(TestMasterDryRunBalancer.class);
+
+  private static final HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
+  private static final byte[] FAMILYNAME = Bytes.toBytes("fam");
+
+  @After
+  public void shutdown() throws Exception {
+    TEST_UTIL.shutdownMiniCluster();
+  }
+
+  @Test
+  public void testDryRunBalancer() throws Exception {
+    TEST_UTIL.startMiniCluster(2);
+
+    int numRegions = 100;
+    int regionsPerRs = numRegions / 2;
+    TableName tableName = createTable("testDryRunBalancer", numRegions);
+    HMaster master = Mockito.spy(TEST_UTIL.getHBaseCluster().getMaster());
+
+    // dry run should be possible with balancer disabled
+    // disabling it will ensure the chore does not mess with our forced 
unbalance below
+    master.balanceSwitch(false);
+    assertFalse(master.isBalancerOn());
+
+    HRegionServer biasedServer = unbalance(master, tableName);
+
+    BalanceResponse response = 
master.balance(BalanceRequest.newBuilder().setDryRun(true).build());
+    assertTrue(response.isBalancerRan());
+    // we don't know for sure that it will be exactly half the regions
+    assertTrue(
+      response.getMovesCalculated() >= (regionsPerRs - 1)
+        && response.getMovesCalculated() <= (regionsPerRs + 1));
+    // but we expect no moves executed due to dry run
+    assertEquals(0, response.getMovesExecuted());
+
+    // sanity check that we truly don't try to execute any plans
+    Mockito.verify(master, 
Mockito.never()).executeRegionPlansWithThrottling(Mockito.anyList());
+
+    // should still be unbalanced post dry run
+    assertServerContainsAllRegions(biasedServer.getServerName(), tableName);
+
+    TEST_UTIL.deleteTable(tableName);
+  }
+
+  private TableName createTable(String table, int numRegions) throws 
IOException {
+    TableName tableName = TableName.valueOf(table);
+    TEST_UTIL.createMultiRegionTable(tableName, FAMILYNAME, numRegions);
+    return tableName;
+  }
+
+
+  private HRegionServer unbalance(HMaster master, TableName tableName) throws 
Exception {
+    waitForRegionsToSettle(master);
+
+    HRegionServer biasedServer = 
TEST_UTIL.getMiniHBaseCluster().getRegionServer(0);
+
+    for (RegionInfo regionInfo : TEST_UTIL.getAdmin().getRegions(tableName)) {
+      master.move(regionInfo.getEncodedNameAsBytes(),
+        Bytes.toBytes(biasedServer.getServerName().getServerName()));
+    }
+
+    waitForRegionsToSettle(master);
+
+    assertServerContainsAllRegions(biasedServer.getServerName(), tableName);
+
+    return biasedServer;
+  }
+
+  private void assertServerContainsAllRegions(ServerName serverName, TableName 
tableName)
+    throws IOException {
+    int numRegions = TEST_UTIL.getAdmin().getRegions(tableName).size();
+    assertEquals(numRegions,
+      
TEST_UTIL.getMiniHBaseCluster().getRegionServer(serverName).getRegions(tableName).size());
+  }
+
+  private void waitForRegionsToSettle(HMaster master) {
+    Waiter.waitFor(TEST_UTIL.getConfiguration(), 60_000,
+      () -> 
master.getAssignmentManager().getRegionStates().getRegionsInTransitionCount() 
<= 0);
+  }
+}
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestProcedurePriority.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestProcedurePriority.java
index f1b7d57..49c7d28 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestProcedurePriority.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/master/procedure/TestProcedurePriority.java
@@ -30,6 +30,7 @@ import org.apache.hadoop.hbase.HBaseTestingUtil;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.Waiter.ExplainingPredicate;
 import org.apache.hadoop.hbase.client.AsyncAdmin;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Durability;
 import org.apache.hadoop.hbase.client.Get;
@@ -126,7 +127,7 @@ public class TestProcedurePriority {
     for (Future<?> future : futures) {
       future.get(3, TimeUnit.MINUTES);
     }
-    UTIL.getAdmin().balance(true);
+    
UTIL.getAdmin().balance(BalanceRequest.newBuilder().setIgnoreRegionsInTransition(true).build());
     UTIL.waitUntilNoRegionsInTransition();
   }
 
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBalance.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBalance.java
index 5137b35..12b8378 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBalance.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBalance.java
@@ -30,6 +30,8 @@ import org.apache.hadoop.hbase.ServerName;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.Waiter;
 import org.apache.hadoop.hbase.Waiter.Predicate;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.TableDescriptor;
@@ -79,12 +81,65 @@ public class TestRSGroupsBalance extends TestRSGroupsBase {
 
   @Test
   public void testGroupBalance() throws Exception {
-    LOG.info(name.getMethodName());
-    String newGroupName = getGroupName(name.getMethodName());
+    String methodName = name.getMethodName();
+
+    LOG.info(methodName);
+    String newGroupName = getGroupName(methodName);
+    TableName tableName = TableName.valueOf(TABLE_PREFIX + "_ns", methodName);
+
+    ServerName first = setupBalanceTest(newGroupName, tableName);
+
+    // balance the other group and make sure it doesn't affect the new group
+    ADMIN.balancerSwitch(true, true);
+    ADMIN.balanceRSGroup(RSGroupInfo.DEFAULT_GROUP);
+    assertEquals(6, 
getTableServerRegionMap().get(tableName).get(first).size());
+
+    // disable balance, balancer will not be run and return false
+    ADMIN.balancerSwitch(false, true);
+    assertFalse(ADMIN.balanceRSGroup(newGroupName).isBalancerRan());
+    assertEquals(6, 
getTableServerRegionMap().get(tableName).get(first).size());
+
+    // enable balance
+    ADMIN.balancerSwitch(true, true);
+    ADMIN.balanceRSGroup(newGroupName);
+    TEST_UTIL.waitFor(WAIT_TIMEOUT, new Waiter.Predicate<Exception>() {
+      @Override
+      public boolean evaluate() throws Exception {
+        for (List<String> regions : 
getTableServerRegionMap().get(tableName).values()) {
+          if (2 != regions.size()) {
+            return false;
+          }
+        }
+        return true;
+      }
+    });
+    ADMIN.balancerSwitch(false, true);
+  }
+
+  @Test
+  public void testGroupDryRunBalance() throws Exception {
+    String methodName = name.getMethodName();
+
+    LOG.info(methodName);
+    String newGroupName = getGroupName(methodName);
+    final TableName tableName = TableName.valueOf(TABLE_PREFIX + "_ns", 
methodName);
+
+    ServerName first = setupBalanceTest(newGroupName, tableName);
+
+    // run the balancer in dry run mode. it should return true, but should not 
actually move any regions
+    ADMIN.balancerSwitch(true, true);
+    BalanceResponse response = ADMIN.balanceRSGroup(newGroupName,
+      BalanceRequest.newBuilder().setDryRun(true).build());
+    assertTrue(response.isBalancerRan());
+    assertTrue(response.getMovesCalculated() > 0);
+    assertEquals(0, response.getMovesExecuted());
+    // validate imbalance still exists.
+    assertEquals(6, 
getTableServerRegionMap().get(tableName).get(first).size());
+  }
+
+  private ServerName setupBalanceTest(String newGroupName, TableName 
tableName) throws Exception {
     addGroup(newGroupName, 3);
 
-    final TableName tableName =
-      TableName.valueOf(TABLE_PREFIX + "_ns", 
getNameWithoutIndex(name.getMethodName()));
     
ADMIN.createNamespace(NamespaceDescriptor.create(tableName.getNamespaceAsString())
       .addConfiguration(RSGroupInfo.NAMESPACE_DESC_PROP_GROUP, 
newGroupName).build());
     final TableDescriptor desc = TableDescriptorBuilder.newBuilder(tableName)
@@ -126,31 +181,7 @@ public class TestRSGroupsBalance extends TestRSGroupsBase {
       }
     });
 
-    // balance the other group and make sure it doesn't affect the new group
-    ADMIN.balancerSwitch(true, true);
-    ADMIN.balanceRSGroup(RSGroupInfo.DEFAULT_GROUP);
-    assertEquals(6, 
getTableServerRegionMap().get(tableName).get(first).size());
-
-    // disable balance, balancer will not be run and return false
-    ADMIN.balancerSwitch(false, true);
-    assertFalse(ADMIN.balanceRSGroup(newGroupName));
-    assertEquals(6, 
getTableServerRegionMap().get(tableName).get(first).size());
-
-    // enable balance
-    ADMIN.balancerSwitch(true, true);
-    ADMIN.balanceRSGroup(newGroupName);
-    TEST_UTIL.waitFor(WAIT_TIMEOUT, new Waiter.Predicate<Exception>() {
-      @Override
-      public boolean evaluate() throws Exception {
-        for (List<String> regions : 
getTableServerRegionMap().get(tableName).values()) {
-          if (2 != regions.size()) {
-            return false;
-          }
-        }
-        return true;
-      }
-    });
-    ADMIN.balancerSwitch(false, true);
+    return first;
   }
 
   @Test
@@ -168,7 +199,7 @@ public class TestRSGroupsBalance extends TestRSGroupsBase {
       .addConfiguration(RSGroupInfo.NAMESPACE_DESC_PROP_GROUP, 
rsGroupInfo.getName()).build());
 
     ADMIN.balancerSwitch(true, true);
-    assertTrue(ADMIN.balanceRSGroup(rsGroupInfo.getName()));
+    assertTrue(ADMIN.balanceRSGroup(rsGroupInfo.getName()).isBalancerRan());
     ADMIN.balancerSwitch(false, true);
     assertTrue(OBSERVER.preBalanceRSGroupCalled);
     assertTrue(OBSERVER.postBalanceRSGroupCalled);
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBase.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBase.java
index 418aaf9..10bd386 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBase.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsBase.java
@@ -43,6 +43,8 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.Waiter;
 import org.apache.hadoop.hbase.client.AbstractTestUpdateConfiguration;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.RegionInfo;
 import org.apache.hadoop.hbase.client.TableDescriptor;
 import org.apache.hadoop.hbase.coprocessor.CoprocessorHost;
@@ -453,13 +455,13 @@ public abstract class TestRSGroupsBase extends 
AbstractTestUpdateConfiguration {
 
     @Override
     public void preBalanceRSGroup(final 
ObserverContext<MasterCoprocessorEnvironment> ctx,
-      String groupName) throws IOException {
+        String groupName, BalanceRequest request) throws IOException {
       preBalanceRSGroupCalled = true;
     }
 
     @Override
     public void postBalanceRSGroup(final 
ObserverContext<MasterCoprocessorEnvironment> ctx,
-      String groupName, boolean balancerRan) throws IOException {
+        String groupName, BalanceRequest request, BalanceResponse response) 
throws IOException {
       postBalanceRSGroupCalled = true;
     }
 
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsFallback.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsFallback.java
index 4478d37..9b78d4c 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsFallback.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/TestRSGroupsFallback.java
@@ -106,7 +106,7 @@ public class TestRSGroupsFallback extends TestRSGroupsBase {
 
     // add a new server to default group, regions move to default group
     TEST_UTIL.getMiniHBaseCluster().startRegionServerAndWait(60000);
-    assertTrue(MASTER.balance());
+    assertTrue(MASTER.balance().isBalancerRan());
     assertRegionsInGroup(tableName, RSGroupInfo.DEFAULT_GROUP);
 
     // add a new server to test group, regions move back
@@ -114,7 +114,7 @@ public class TestRSGroupsFallback extends TestRSGroupsBase {
       TEST_UTIL.getMiniHBaseCluster().startRegionServerAndWait(60000);
     ADMIN.moveServersToRSGroup(
       Collections.singleton(t.getRegionServer().getServerName().getAddress()), 
groupName);
-    assertTrue(MASTER.balance());
+    assertTrue(MASTER.balance().isBalancerRan());
     assertRegionsInGroup(tableName, groupName);
 
     TEST_UTIL.deleteTable(tableName);
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java
index 57b87e5..c5911f2 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/rsgroup/VerifyingRSGroupAdmin.java
@@ -44,6 +44,8 @@ import org.apache.hadoop.hbase.TableExistsException;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceRequest;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
 import org.apache.hadoop.hbase.client.CompactType;
 import org.apache.hadoop.hbase.client.CompactionState;
@@ -329,12 +331,8 @@ public class VerifyingRSGroupAdmin implements Admin, 
Closeable {
     return admin.balancerSwitch(onOrOff, synchronous);
   }
 
-  public boolean balance() throws IOException {
-    return admin.balance();
-  }
-
-  public boolean balance(boolean force) throws IOException {
-    return admin.balance(force);
+  public BalanceResponse balance(BalanceRequest request) throws IOException {
+    return admin.balance(request);
   }
 
   public boolean isBalancerEnabled() throws IOException {
@@ -829,8 +827,8 @@ public class VerifyingRSGroupAdmin implements Admin, 
Closeable {
     verify();
   }
 
-  public boolean balanceRSGroup(String groupName) throws IOException {
-    return admin.balanceRSGroup(groupName);
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) throws IOException {
+    return admin.balanceRSGroup(groupName, request);
   }
 
   @Override
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java
index 5f2c6ac..721497a 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestAccessController.java
@@ -24,7 +24,6 @@ import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 import static org.junit.Assert.fail;
-
 import java.io.IOException;
 import java.security.PrivilegedAction;
 import java.util.ArrayList;
@@ -34,7 +33,6 @@ import java.util.Collections;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
-
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.CommonConfigurationKeys;
 import org.apache.hadoop.fs.FileStatus;
@@ -56,6 +54,7 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Admin;
 import org.apache.hadoop.hbase.client.Append;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Connection;
@@ -130,13 +129,11 @@ import org.junit.experimental.categories.Category;
 import org.junit.rules.TestName;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.apache.hbase.thirdparty.com.google.protobuf.BlockingRpcChannel;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcCallback;
 import org.apache.hbase.thirdparty.com.google.protobuf.RpcController;
 import org.apache.hbase.thirdparty.com.google.protobuf.Service;
 import org.apache.hbase.thirdparty.com.google.protobuf.ServiceException;
-
 import 
org.apache.hadoop.hbase.shaded.coprocessor.protobuf.generated.PingProtos.CountRequest;
 import 
org.apache.hadoop.hbase.shaded.coprocessor.protobuf.generated.PingProtos.CountResponse;
 import 
org.apache.hadoop.hbase.shaded.coprocessor.protobuf.generated.PingProtos.HelloRequest;
@@ -789,7 +786,8 @@ public class TestAccessController extends SecureTestUtil {
     AccessTestAction action = new AccessTestAction() {
       @Override
       public Object run() throws Exception {
-        
ACCESS_CONTROLLER.preBalance(ObserverContextImpl.createAndPrepare(CP_ENV));
+        
ACCESS_CONTROLLER.preBalance(ObserverContextImpl.createAndPrepare(CP_ENV),
+          BalanceRequest.defaultInstance());
         return null;
       }
     };
diff --git 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestWithDisabledAuthorization.java
 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestWithDisabledAuthorization.java
index 2b50ea4..749b3de 100644
--- 
a/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestWithDisabledAuthorization.java
+++ 
b/hbase-server/src/test/java/org/apache/hadoop/hbase/security/access/TestWithDisabledAuthorization.java
@@ -18,7 +18,6 @@
 package org.apache.hadoop.hbase.security.access;
 
 import static org.junit.Assert.assertEquals;
-
 import java.util.List;
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.hbase.Cell;
@@ -33,6 +32,7 @@ import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNameTestRule;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Append;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
 import org.apache.hadoop.hbase.client.Connection;
 import org.apache.hadoop.hbase.client.ConnectionFactory;
@@ -78,7 +78,6 @@ import org.junit.Test;
 import org.junit.experimental.categories.Category;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
-
 import org.apache.hbase.thirdparty.com.google.common.collect.Lists;
 
 @Category({SecurityTests.class, LargeTests.class})
@@ -574,7 +573,8 @@ public class TestWithDisabledAuthorization extends 
SecureTestUtil {
     verifyAllowed(new AccessTestAction() {
       @Override
       public Object run() throws Exception {
-        
ACCESS_CONTROLLER.preBalance(ObserverContextImpl.createAndPrepare(CP_ENV));
+        
ACCESS_CONTROLLER.preBalance(ObserverContextImpl.createAndPrepare(CP_ENV),
+          BalanceRequest.defaultInstance());
         return null;
       }
     }, SUPERUSER, USER_ADMIN, USER_RW, USER_RO, USER_OWNER, USER_CREATE, 
USER_QUAL, USER_NONE);
diff --git a/hbase-shell/src/main/ruby/hbase/admin.rb 
b/hbase-shell/src/main/ruby/hbase/admin.rb
index ee9a449..0d02dba 100644
--- a/hbase-shell/src/main/ruby/hbase/admin.rb
+++ b/hbase-shell/src/main/ruby/hbase/admin.rb
@@ -30,6 +30,8 @@ java_import 
org.apache.hadoop.hbase.client.CoprocessorDescriptorBuilder
 java_import org.apache.hadoop.hbase.client.TableDescriptorBuilder
 java_import org.apache.hadoop.hbase.HConstants
 
+require 'hbase/balancer_utils'
+
 # Wrapper for org.apache.hadoop.hbase.client.HBaseAdmin
 
 module Hbase
@@ -230,9 +232,10 @@ module Hbase
 
     
#----------------------------------------------------------------------------------------------
     # Requests a cluster balance
-    # Returns true if balancer ran
-    def balancer(force)
-      @admin.balance(java.lang.Boolean.valueOf(force))
+    # Returns BalanceResponse with details of the balancer run
+    def balancer(*args)
+      request = ::Hbase::BalancerUtils.create_balance_request(args)
+      @admin.balance(request)
     end
 
     
#----------------------------------------------------------------------------------------------
diff --git a/hbase-shell/src/main/ruby/hbase/balancer_utils.rb 
b/hbase-shell/src/main/ruby/hbase/balancer_utils.rb
new file mode 100644
index 0000000..9948c0f
--- /dev/null
+++ b/hbase-shell/src/main/ruby/hbase/balancer_utils.rb
@@ -0,0 +1,57 @@
+#
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+include Java
+
+java_import org.apache.hadoop.hbase.client.BalanceRequest
+
+module Hbase
+  class BalancerUtils
+    def self.create_balance_request(args)
+      args = args.first if args.first.is_a?(Array) and args.size == 1
+      if args.nil? or args.empty?
+        return BalanceRequest.defaultInstance()
+      elsif args.size > 2
+        raise ArgumentError, "Illegal arguments #{args}. Expected between 0 
and 2 arguments, but got #{args.size}."
+      end
+
+      builder = BalanceRequest.newBuilder()
+
+      index = 0
+      args.each do |arg|
+        if !arg.is_a?(String)
+          raise ArgumentError, "Illegal argument in index #{index}: #{arg}. 
All arguments must be strings, but got #{arg.class}."
+        end
+
+        case arg
+        when 'force', 'ignore_rit'
+          builder.setIgnoreRegionsInTransition(true)
+        when 'dry_run'
+          builder.setDryRun(true)
+        else
+          raise ArgumentError, "Illegal argument in index #{index}: #{arg}. 
Unknown option #{arg}, expected 'force', 'ignore_rit', or 'dry_run'."
+        end
+
+        index += 1
+      end
+
+      return builder.build()
+    end
+  end
+end
diff --git a/hbase-shell/src/main/ruby/hbase/rsgroup_admin.rb 
b/hbase-shell/src/main/ruby/hbase/rsgroup_admin.rb
index dfffb56..074ef45 100644
--- a/hbase-shell/src/main/ruby/hbase/rsgroup_admin.rb
+++ b/hbase-shell/src/main/ruby/hbase/rsgroup_admin.rb
@@ -18,6 +18,8 @@
 include Java
 java_import org.apache.hadoop.hbase.util.Pair
 
+require 'hbase/balancer_utils'
+
 # Wrapper for org.apache.hadoop.hbase.group.GroupAdminClient
 # Which is an API to manage region server groups
 
@@ -60,8 +62,9 @@ module Hbase
 
     #--------------------------------------------------------------------------
     # balance a group
-    def balance_rs_group(group_name)
-      @admin.balanceRSGroup(group_name)
+    def balance_rs_group(group_name, *args)
+      request = ::Hbase::BalancerUtils.create_balance_request(args)
+      @admin.balanceRSGroup(group_name, request)
     end
 
     #--------------------------------------------------------------------------
diff --git a/hbase-shell/src/main/ruby/shell/commands/balance_rsgroup.rb 
b/hbase-shell/src/main/ruby/shell/commands/balance_rsgroup.rb
index a223e05..aff9fa7 100644
--- a/hbase-shell/src/main/ruby/shell/commands/balance_rsgroup.rb
+++ b/hbase-shell/src/main/ruby/shell/commands/balance_rsgroup.rb
@@ -22,22 +22,32 @@ module Shell
         <<-EOF
 Balance a RegionServer group
 
+Parameter can be "force" or "dry_run":
+ - "dry_run" will run the balancer to generate a plan, but will not actually 
execute that plan.
+   This is useful for testing out new balance configurations. See the active 
HMaster logs for the results of the dry_run.
+ - "ignore_rit" tells master whether we should force the balancer to run even 
if there is region in transition.
+   WARNING: For experts only. Forcing a balance may do more damage than repair 
when assignment is confused
+
 Example:
 
   hbase> balance_rsgroup 'my_group'
+  hbase> balance_rsgroup 'my_group', 'ignore_rit'
+  hbase> balance_rsgroup 'my_group', 'dry_run'
+  hbase> balance_rsgroup 'my_group', 'dry_run', 'ignore_rit'
 
 EOF
       end
 
-      def command(group_name)
+      def command(group_name, *args)
         # Returns true if balancer was run, otherwise false.
-        ret = rsgroup_admin.balance_rs_group(group_name)
-        if ret
-          puts 'Ran the balancer.'
+        resp = rsgroup_admin.balance_rs_group(group_name, args)
+        if resp.isBalancerRan
+          formatter.row(["Balancer ran"])
+          formatter.row(["Moves calculated: #{resp.getMovesCalculated}, moves 
executed: #{resp.getMovesExecuted}"])
         else
-          puts "Couldn't run the balancer."
+          formatter.row(["Balancer did not run. See logs for details."])
         end
-        ret
+        resp.isBalancerRan
       end
     end
   end
diff --git a/hbase-shell/src/main/ruby/shell/commands/balancer.rb 
b/hbase-shell/src/main/ruby/shell/commands/balancer.rb
index c4acdc0..d5304e0 100644
--- a/hbase-shell/src/main/ruby/shell/commands/balancer.rb
+++ b/hbase-shell/src/main/ruby/shell/commands/balancer.rb
@@ -22,31 +22,32 @@ module Shell
     class Balancer < Command
       def help
         <<-EOF
-Trigger the cluster balancer. Returns true if balancer ran and was able to
-tell the region servers to unassign all the regions to balance  (the 
re-assignment itself is async).
-Otherwise false (Will not run if regions in transition).
-Parameter tells master whether we should force balance even if there is region 
in transition.
+Trigger the cluster balancer. Returns true if balancer ran, otherwise false 
(Will not run if regions in transition).
 
-WARNING: For experts only. Forcing a balance may do more damage than repair
-when assignment is confused
+Parameter can be "force" or "dry_run":
+ - "dry_run" will run the balancer to generate a plan, but will not actually 
execute that plan.
+   This is useful for testing out new balance configurations. See the active 
HMaster logs for the results of the dry_run.
+ - "ignore_rit" tells master whether we should force the balancer to run even 
if there is region in transition.
+   WARNING: For experts only. Forcing a balance may do more damage than repair 
when assignment is confused
 
 Examples:
 
   hbase> balancer
-  hbase> balancer "force"
+  hbase> balancer "ignore_rit"
+  hbase> balancer "dry_run"
+  hbase> balancer "dry_run", "ignore_rit"
 EOF
       end
 
-      def command(force = nil)
-        force_balancer = 'false'
-        if force == 'force'
-          force_balancer = 'true'
-        elsif !force.nil?
-          raise ArgumentError, "Invalid argument #{force}."
+      def command(*args)
+        resp = admin.balancer(args)
+        if resp.isBalancerRan
+          formatter.row(["Balancer ran"])
+          formatter.row(["Moves calculated: #{resp.getMovesCalculated}, moves 
executed: #{resp.getMovesExecuted}"])
+        else
+          formatter.row(["Balancer did not run. See logs for details."])
         end
-        did_balancer_run = !!admin.balancer(force_balancer)
-        formatter.row([did_balancer_run.to_s])
-        did_balancer_run
+        resp.isBalancerRan
       end
     end
   end
diff --git a/hbase-shell/src/test/ruby/hbase/admin_test.rb 
b/hbase-shell/src/test/ruby/hbase/admin_test.rb
index 9e7096d..957c018 100644
--- a/hbase-shell/src/test/ruby/hbase/admin_test.rb
+++ b/hbase-shell/src/test/ruby/hbase/admin_test.rb
@@ -202,7 +202,13 @@ module Hbase
       did_balancer_run = command(:balancer)
       assert(did_balancer_run == true)
       output = capture_stdout { command(:balancer, 'force') }
-      assert(output.include?('true'))
+      assert(output.include?('Balancer ran'))
+
+      command(:balance_switch, false)
+      output = capture_stdout { command(:balancer) }
+      assert(output.include?('Balancer did not run'))
+      output = capture_stdout { command(:balancer, 'dry_run') }
+      assert(output.include?('Balancer ran'))
     end
 
     
#-------------------------------------------------------------------------------
diff --git a/hbase-shell/src/test/ruby/hbase/balancer_utils_test.rb 
b/hbase-shell/src/test/ruby/hbase/balancer_utils_test.rb
new file mode 100644
index 0000000..9d70540
--- /dev/null
+++ b/hbase-shell/src/test/ruby/hbase/balancer_utils_test.rb
@@ -0,0 +1,78 @@
+#
+#
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+java_import org.apache.hadoop.hbase.client.BalanceRequest
+
+module Hbase
+  class BalancerUtilsTest < Test::Unit::TestCase
+    include TestHelpers
+
+    def create_balance_request(*args)
+       ::Hbase::BalancerUtils.create_balance_request(args)
+    end
+
+    define_test "should raise ArgumentError on unknown string argument" do
+      assert_raise(ArgumentError) do
+        request = create_balance_request('foo')
+      end
+    end
+
+    define_test "should raise ArgumentError on non-array argument" do
+      assert_raise(ArgumentError) do
+        request = create_balance_request({foo: 'bar' })
+      end
+    end
+
+    define_test "should raise ArgumentError on non-string array item" do
+      assert_raise(ArgumentError) do
+        request = create_balance_request('force', true)
+      end
+    end
+
+    define_test "should parse empty args" do
+      request = create_balance_request()
+      assert(!request.isDryRun())
+      assert(!request.isIgnoreRegionsInTransition())
+    end
+
+    define_test "should parse 'force' string" do
+      request = create_balance_request('force')
+      assert(!request.isDryRun())
+      assert(request.isIgnoreRegionsInTransition())
+    end
+    
+    define_test "should parse 'ignore_rit' string" do
+      request = create_balance_request('ignore_rit')
+      assert(!request.isDryRun())
+      assert(request.isIgnoreRegionsInTransition())
+    end
+
+    define_test "should parse 'dry_run' string" do
+      request = create_balance_request('dry_run')
+      assert(request.isDryRun())
+      assert(!request.isIgnoreRegionsInTransition())
+    end
+
+    define_test "should parse multiple string args" do
+      request = create_balance_request('dry_run', 'ignore_rit')
+      assert(request.isDryRun())
+      assert(request.isIgnoreRegionsInTransition())
+    end
+  end
+end
diff --git a/hbase-shell/src/test/ruby/shell/rsgroup_shell_test.rb 
b/hbase-shell/src/test/ruby/shell/rsgroup_shell_test.rb
index f93d364..56b6a8e 100644
--- a/hbase-shell/src/test/ruby/shell/rsgroup_shell_test.rb
+++ b/hbase-shell/src/test/ruby/shell/rsgroup_shell_test.rb
@@ -89,6 +89,8 @@ module Hbase
 
       # just run it to verify jruby->java api binding
       @hbase.rsgroup_admin.balance_rs_group(group_name)
+      @hbase.rsgroup_admin.balance_rs_group(group_name, 'force')
+      @hbase.rsgroup_admin.balance_rs_group(group_name, 'dry_run')
 
       @shell.command(:disable, table_name)
       @shell.command(:drop, table_name)
diff --git 
a/hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/client/ThriftAdmin.java
 
b/hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/client/ThriftAdmin.java
index 86f4268..2b54525 100644
--- 
a/hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/client/ThriftAdmin.java
+++ 
b/hbase-thrift/src/main/java/org/apache/hadoop/hbase/thrift2/client/ThriftAdmin.java
@@ -27,6 +27,7 @@ import java.util.concurrent.Future;
 import java.util.regex.Pattern;
 import org.apache.commons.lang3.NotImplementedException;
 import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.client.BalanceRequest;
 import org.apache.hadoop.hbase.CacheEvictionStats;
 import org.apache.hadoop.hbase.ClusterMetrics;
 import org.apache.hadoop.hbase.HConstants;
@@ -38,6 +39,7 @@ import org.apache.hadoop.hbase.TableExistsException;
 import org.apache.hadoop.hbase.TableName;
 import org.apache.hadoop.hbase.TableNotFoundException;
 import org.apache.hadoop.hbase.client.Admin;
+import org.apache.hadoop.hbase.client.BalanceResponse;
 import org.apache.hadoop.hbase.client.ColumnFamilyDescriptor;
 import org.apache.hadoop.hbase.client.CompactType;
 import org.apache.hadoop.hbase.client.CompactionState;
@@ -630,6 +632,11 @@ public class ThriftAdmin implements Admin {
   }
 
   @Override
+  public BalanceResponse balance(BalanceRequest request) throws IOException {
+    throw new NotImplementedException("balance not supported in ThriftAdmin");
+  }
+
+  @Override
   public boolean isBalancerEnabled() {
     throw new NotImplementedException("isBalancerEnabled not supported in 
ThriftAdmin");
   }
@@ -1228,7 +1235,7 @@ public class ThriftAdmin implements Admin {
   }
 
   @Override
-  public boolean balanceRSGroup(String groupName) {
+  public BalanceResponse balanceRSGroup(String groupName, BalanceRequest 
request) {
     throw new NotImplementedException("balanceRSGroup not supported in 
ThriftAdmin");
   }
 

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