Mailing-List: contact dev-help@accumulo.apache.org; run by ezmlm
Precedence: bulk
Reply-To: dev@accumulo.apache.org
From: joshelser <git@git.apache.org>
To: dev@accumulo.apache.org
Reply-To: dev@accumulo.apache.org
References: <git-pr-83-accumulo@git.apache.org>
In-Reply-To: <git-pr-83-accumulo@git.apache.org>
Subject: [GitHub] accumulo pull request: ACCUMULO-4173: Host Regex Table Load
 Balanc...
Content-Type: text/plain
Message-Id: <20160330181301.64910DFC71@git1-us-west.apache.org>
Date: Wed, 30 Mar 2016 18:13:01 +0000 (UTC)

Github user joshelser commented on a diff in the pull request:

    https://github.com/apache/accumulo/pull/83#discussion_r57936424
  
    --- 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.&lt;tablename&gt;=&lt;regex&gt;</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()) {
    --- End diff --
    
    There's logic to handle configuration updates via a Callback. Seems logical that active Balancer could also tie into that callback to process configuration updates. (could be follow-on work since it already doesn't do that)


---
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 infrastructure@apache.org or file a JIRA ticket
with INFRA.
---