Github user brianloss commented on a diff in the pull request:
https://github.com/apache/accumulo/pull/83#discussion_r57933756
--- Diff:
server/base/src/main/java/org/apache/accumulo/server/master/balancer/HostRegexTableLoadBalancer.java
---
@@ -0,0 +1,314 @@
+/*
+ * 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. <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 long lastOOBCheck = System.currentTimeMillis();
+ private 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 ppol.
+ *
+ * @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) {
+ Map<String,SortedMap<TServerInstance,TabletServerStatus>> newPools =
new HashMap<String,SortedMap<TServerInstance,TabletServerStatus>>();
+ for (Entry<TServerInstance,TabletServerStatus> e :
current.entrySet()) {
+ String tableName = getPoolNameForHost(e.getKey().host());
+ if (!newPools.containsKey(tableName)) {
+ newPools.put(tableName, new
TreeMap<TServerInstance,TabletServerStatus>());
+ }
+ newPools.get(tableName).put(e.getKey(), e.getValue());
+ }
+ // Ensure that no host is in more than one pool
+ // TODO: I'm not sure that I need to check for disjoint as the call
to getPoolNameForHost checks for more than one match
+ boolean error = false;
+ for (SortedMap<TServerInstance,TabletServerStatus> s1 :
newPools.values()) {
+ for (SortedMap<TServerInstance,TabletServerStatus> s2 :
newPools.values()) {
+ if (s1 == s2) {
+ continue;
+ }
+ if (!Collections.disjoint(s1.keySet(), s2.keySet())) {
+ LOG.error("Pools are not disjoint: {}, there is a problem with
your regular expressions. Putting all servers in default pool", newPools);
+ error = true;
+ }
+ }
+ }
+ if (error) {
+ // Put all servers into the default pool
+ newPools.clear();
+ newPools.put(DEFAULT_POOL, new
TreeMap<TServerInstance,TabletServerStatus>());
+ for (Entry<TServerInstance,TabletServerStatus> e :
current.entrySet()) {
+ newPools.get(DEFAULT_POOL).put(e.getKey(), e.getValue());
+ }
+ }
+ pools = newPools;
+ this.lastPoolRecheck = System.currentTimeMillis();
+ }
+ return pools;
+ }
+
+ /**
+ * Matches host against the regexes and returns the matching pool name
+ *
+ * @param host
+ * tablet server host
+ * @return name of pool. will return default pool if host matches more
than one regex
+ */
+ protected String getPoolNameForHost(String host) {
+ String test = host;
+ String table = DEFAULT_POOL;
+ 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 table;
+ }
+ }
+ for (Entry<String,Pattern> e : poolNameToRegexPattern.entrySet()) {
+ if (e.getValue().matcher(test).matches()) {
+ if (!table.equals(DEFAULT_POOL)) {
+ LOG.warn("host {} matches more than one regex, assigning to
default pool", host);
+ return DEFAULT_POOL;
+ }
+ table = e.getKey();
+ }
+ }
+ return table;
+ }
+
+ 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()) {
+ 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) {
+
+ if ((System.currentTimeMillis() - this.lastOOBCheck) >
this.oobCheckMillis) {
+ // Check to see if a tablet is assigned outside the bounds of the
pool. If so, migrate it.
+ for (Entry<TServerInstance,TabletServerStatus> e :
current.entrySet()) {
+ String assignedPool = getPoolNameForHost(e.getKey().host());
+ for (String pool : poolNameToRegexPattern.keySet()) {
+ if (assignedPool.equals(pool) || pool.equals(DEFAULT_POOL)) {
+ continue;
+ }
+ String tid = getTableOperations().tableIdMap().get(pool);
+ try {
+ List<TabletStats> outOfBoundsTablets =
getOnlineTabletsForTable(e.getKey(), tid);
+ for (TabletStats ts : outOfBoundsTablets) {
+ LOG.info("Tablet {} is currently outside the bounds of the
regex, reassigning", ts.toString());
+ unassigned.put(new KeyExtent(ts.getExtent()), e.getKey());
--- End diff --
getAssignments is for making assignments where there isn't one currently.
Is it safe to take a tablet that is already assigned, and generate a new
assignment here? It might be totally fine--but it's something to verify.
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
