Github user joshelser commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/83#discussion_r59384715
--- Diff:
server/base/src/main/java/org/apache/accumulo/server/master/balancer/HostRegexTableLoadBalancer.java
---
@@ -0,0 +1,334 @@
+/*
+ * 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.accumulo.server.master.balancer;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+import java.util.Set;
+import java.util.SortedMap;
+import java.util.TreeMap;
+import java.util.regex.Pattern;
+
+import org.apache.accumulo.core.client.admin.TableOperations;
+import org.apache.accumulo.core.conf.AccumuloConfiguration;
+import org.apache.accumulo.core.conf.Property;
+import org.apache.accumulo.core.data.impl.KeyExtent;
+import org.apache.accumulo.core.master.thrift.TabletServerStatus;
+import org.apache.accumulo.core.tabletserver.thrift.TabletStats;
+import org.apache.accumulo.server.conf.ServerConfiguration;
+import org.apache.accumulo.server.master.state.TServerInstance;
+import org.apache.accumulo.server.master.state.TabletMigration;
+import org.apache.thrift.TException;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This balancer will create pools of tablet servers by grouping tablet
servers that match a regex into the same pool and calling the balancer set on
the table
+ * to balance within the set of matching tablet servers. All tablet
servers that do not match a regex are grouped into a default pool.<br>
+ * Regex properties for this balancer are specified as:<br>
+ *
<b>table.custom.balancer.host.regex.<tablename>=<regex></b><br>
+ * Periodically (default 5m) this balancer will check to see if a tablet
server is hosting tablets that it should not be according to the regex
configuration.
+ * If this occurs then the offending tablets will be reassigned. This
would cover the case where the configuration is changed and the master is
restarted while
+ * the tablet servers are up. To change the out of bounds check time
period, set the following property:<br>
+ * <b>table.custom.balancer.host.regex.oob.period=5m</b><br>
+ * Periodically (default 5m) this balancer will regroup the set of current
tablet servers into pools based on regexes applied to the tserver host names.
This
+ * would cover the case of tservers dying or coming online. To change the
host pool check time period, set the following property: <br>
+ * <b>table.custom.balancer.host.regex.pool.check=5m</b><br>
+ * Regex matching can be based on either the host name (default) or host
ip address. To set this balancer to match the regular expressions to the tablet
server
+ * IP address, then set the following property:<br>
+ * <b>table.custom.balancer.host.regex.is.ip=true</b>
+ *
+ */
+public class HostRegexTableLoadBalancer extends TableLoadBalancer {
+
+ private static final Logger LOG =
LoggerFactory.getLogger(HostRegexTableLoadBalancer.class);
+ public static final String HOST_BALANCER_PREFIX =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() + "balancer.host.regex.";
+ public static final String HOST_BALANCER_OOB_CHECK =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() +
"balancer.host.regex.oob.period";
+ private static final String HOST_BALANCER_OOB_DEFAULT = "5m";
+ public static final String HOST_BALANCER_POOL_RECHECK_KEY =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() +
"balancer.host.regex.pool.check";
+ private static final String HOST_BALANCER_POOL_RECHECK_DEFAULT = "5m";
+ public static final String HOST_BALANCER_REGEX_USING_IPS =
Property.TABLE_ARBITRARY_PROP_PREFIX.getKey() + "balancer.host.regex.is.ip";
+ protected static final String DEFAULT_POOL = "HostTableLoadBalancer.ALL";
+
+ protected long oobCheckMillis =
AccumuloConfiguration.getTimeInMillis(HOST_BALANCER_OOB_DEFAULT);
+ protected long poolRecheckMillis =
AccumuloConfiguration.getTimeInMillis(HOST_BALANCER_POOL_RECHECK_DEFAULT);
+
+ private Map<String,String> tableIdToTableName = null;
+ private Map<String,Pattern> poolNameToRegexPattern = null;
+ private volatile long lastOOBCheck = System.currentTimeMillis();
+ private volatile long lastPoolRecheck = 0;
+ private boolean isIpBasedRegex = false;
+ private Map<String,SortedMap<TServerInstance,TabletServerStatus>> pools
= new HashMap<String,SortedMap<TServerInstance,TabletServerStatus>>();
+
+ /**
+ * Group the set of current tservers by pool name. Tservers that don't
match a regex are put into a default pool.
+ *
+ * @param current
+ * map of current tservers
+ * @return current servers grouped by pool name, if not a match it is
put into a default pool.
+ */
+ protected synchronized
Map<String,SortedMap<TServerInstance,TabletServerStatus>>
splitCurrentByRegex(SortedMap<TServerInstance,TabletServerStatus> current) {
+ if ((System.currentTimeMillis() - lastPoolRecheck) >
poolRecheckMillis) {
+ LOG.debug("Performing pool recheck - regrouping tablet servers into
pools based on regex");
+ Map<String,SortedMap<TServerInstance,TabletServerStatus>> newPools =
new HashMap<String,SortedMap<TServerInstance,TabletServerStatus>>();
+ for (Entry<TServerInstance,TabletServerStatus> e :
current.entrySet()) {
+ List<String> poolNames = getPoolNamesForHost(e.getKey().host());
+ for (String pool : poolNames) {
+ SortedMap<TServerInstance,TabletServerStatus> np =
newPools.get(pool);
+ if (null == np) {
+ np = new
TreeMap<TServerInstance,TabletServerStatus>(current.comparator());
+ newPools.put(pool, np);
+ }
+ np.put(e.getKey(), e.getValue());
+ }
+ }
+ pools = newPools;
+ this.lastPoolRecheck = System.currentTimeMillis();
+ }
+ return pools;
+ }
+
+ /**
+ * Matches host against the regexes and returns the matching pool names
+ *
+ * @param host
+ * tablet server host
+ * @return pool names, will return default pool if host matches more no
regex
+ */
+ protected List<String> getPoolNamesForHost(String host) {
+ String test = host;
+ if (!isIpBasedRegex) {
+ try {
+ test = getNameFromIp(host);
+ } catch (UnknownHostException e1) {
+ LOG.error("Unable to determine host name for IP: " + host + ",
setting to default pool", e1);
+ return Collections.singletonList(DEFAULT_POOL);
+ }
+ }
+ List<String> pools = new ArrayList<>();
+ for (Entry<String,Pattern> e : poolNameToRegexPattern.entrySet()) {
+ if (e.getValue().matcher(test).matches()) {
+ pools.add(e.getKey());
+ }
+ }
+ if (pools.size() == 0) {
+ pools.add(DEFAULT_POOL);
+ }
+ return pools;
+ }
+
+ protected String getNameFromIp(String hostIp) throws
UnknownHostException {
+ return InetAddress.getByName(hostIp).getHostName();
+ }
+
+ /**
+ * Matches table name against pool names, returns matching pool name or
DEFAULT_POOL.
+ *
+ * @param tableName
+ * name of table
+ * @return tablet server pool name (table name or DEFAULT_POOL)
+ */
+ protected String getPoolNameForTable(String tableName) {
+ if (null == tableName) {
+ return DEFAULT_POOL;
+ }
+ return poolNameToRegexPattern.containsKey(tableName) ? tableName :
DEFAULT_POOL;
+ }
+
+ /**
+ * Parse configuration and extract properties
+ *
+ * @param conf
+ * server configuration
+ */
+ protected void parseConfiguration(ServerConfiguration conf) {
+ tableIdToTableName = new HashMap<>();
+ poolNameToRegexPattern = new HashMap<>();
+ for (Entry<String,String> table :
getTableOperations().tableIdMap().entrySet()) {
+ tableIdToTableName.put(table.getValue(), table.getKey());
+ Map<String,String> customProps =
conf.getTableConfiguration(table.getValue()).getAllPropertiesWithPrefix(Property.TABLE_ARBITRARY_PROP_PREFIX);
+ if (null != customProps && customProps.size() > 0) {
+ for (Entry<String,String> customProp : customProps.entrySet()) {
+ if (customProp.getKey().startsWith(HOST_BALANCER_PREFIX)) {
+ String tableName =
customProp.getKey().substring(HOST_BALANCER_PREFIX.length());
+ String regex = customProp.getValue();
+ poolNameToRegexPattern.put(tableName, Pattern.compile(regex));
+ }
+ }
+ }
+ }
+ String oobProperty =
conf.getConfiguration().get(HOST_BALANCER_OOB_CHECK);
+ if (null != oobProperty) {
+ oobCheckMillis = AccumuloConfiguration.getTimeInMillis(oobProperty);
+ }
+ String poolRecheckProperty =
conf.getConfiguration().get(HOST_BALANCER_POOL_RECHECK_KEY);
+ if (null != poolRecheckProperty) {
+ poolRecheckMillis =
AccumuloConfiguration.getTimeInMillis(poolRecheckProperty);
+ }
+ String ipBased =
conf.getConfiguration().get(HOST_BALANCER_REGEX_USING_IPS);
+ if (null != ipBased) {
+ isIpBasedRegex = Boolean.parseBoolean(ipBased);
+ }
+ }
+
+ public Map<String,String> getTableIdToTableName() {
+ return tableIdToTableName;
+ }
+
+ public Map<String,Pattern> getPoolNameToRegexPattern() {
+ return poolNameToRegexPattern;
+ }
+
+ public long getOobCheckMillis() {
+ return oobCheckMillis;
+ }
+
+ public long getPoolRecheckMillis() {
+ return poolRecheckMillis;
+ }
+
+ public boolean isIpBasedRegex() {
+ return isIpBasedRegex;
+ }
+
+ @Override
+ public void init(ServerConfiguration conf) {
+ super.init(conf);
+ parseConfiguration(conf);
+ }
+
+ @Override
+ public void getAssignments(SortedMap<TServerInstance,TabletServerStatus>
current, Map<KeyExtent,TServerInstance> unassigned,
+ Map<KeyExtent,TServerInstance> assignments) {
+
+ Map<String,SortedMap<TServerInstance,TabletServerStatus>> pools =
splitCurrentByRegex(current);
+ // group the unassigned into tables
+ Map<String,Map<KeyExtent,TServerInstance>> groupedUnassigned = new
HashMap<String,Map<KeyExtent,TServerInstance>>();
+ for (Entry<KeyExtent,TServerInstance> e : unassigned.entrySet()) {
+ Map<KeyExtent,TServerInstance> tableUnassigned =
groupedUnassigned.get(e.getKey().getTableId());
+ if (tableUnassigned == null) {
+ tableUnassigned = new HashMap<KeyExtent,TServerInstance>();
+ groupedUnassigned.put(e.getKey().getTableId(), tableUnassigned);
+ }
+ tableUnassigned.put(e.getKey(), e.getValue());
+ }
+ // Send a view of the current servers to the tables tablet balancer
+ for (Entry<String,Map<KeyExtent,TServerInstance>> e :
groupedUnassigned.entrySet()) {
+ Map<KeyExtent,TServerInstance> newAssignments = new
HashMap<KeyExtent,TServerInstance>();
+ String tableName = tableIdToTableName.get(e.getKey());
+ String poolName = getPoolNameForTable(tableName);
+ SortedMap<TServerInstance,TabletServerStatus> currentView =
pools.get(poolName);
+ if (null == currentView || currentView.size() == 0) {
+ LOG.warn("No tablet servers online for table {}, assigning within
default pool", tableName);
+ currentView = pools.get(DEFAULT_POOL);
+ if (null == currentView) {
+ LOG.error("No tablet servers exist in the default pool, unable
to assign tablets for table {}", tableName);
--- End diff --
Findbugs caught a bug here. You're likely missing a `continue`?. When `null
== currentView`, you'll fall through and call `keySet()` on it.
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