001/*
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hbase.master.balancer;
019
020import java.util.Arrays;
021import java.util.Collections;
022import java.util.List;
023import java.util.Set;
024import java.util.stream.Collectors;
025import org.apache.hadoop.conf.Configuration;
026import org.apache.hadoop.hbase.HBaseInterfaceAudience;
027import org.apache.hadoop.hbase.client.RegionInfo;
028import org.apache.hadoop.hbase.master.RegionPlan;
029import org.apache.yetus.audience.InterfaceAudience;
030import org.apache.yetus.audience.InterfaceStability;
031import org.slf4j.Logger;
032import org.slf4j.LoggerFactory;
033
034@InterfaceAudience.LimitedPrivate(HBaseInterfaceAudience.CONFIG)
035@InterfaceStability.Evolving
036public abstract class RegionPlanConditional {
037  private static final Logger LOG = LoggerFactory.getLogger(RegionPlanConditional.class);
038  private BalancerClusterState cluster;
039
040  RegionPlanConditional(Configuration conf, BalancerClusterState cluster) {
041    this.cluster = cluster;
042  }
043
044  public enum ValidationLevel {
045    /**
046     * Just check the server.
047     */
048    SERVER,
049    /**
050     * Check the server and the host.
051     */
052    SERVER_HOST,
053    /**
054     * Check the server, host, and rack.
055     */
056    SERVER_HOST_RACK
057  }
058
059  void setClusterState(BalancerClusterState cluster) {
060    this.cluster = cluster;
061  }
062
063  /**
064   * Returns a {@link ValidationLevel} that is appropriate for this conditional.
065   * @return the validation level
066   */
067  abstract ValidationLevel getValidationLevel();
068
069  /**
070   * Get the candidate generator(s) for this conditional. This can be useful to provide the balancer
071   * with hints that will appease your conditional. Your conditionals will be triggered in order.
072   * @return the candidate generator for this conditional
073   */
074  abstract List<RegionPlanConditionalCandidateGenerator> getCandidateGenerators();
075
076  /**
077   * Check if the conditional is violated by the given region plan.
078   * @param regionPlan the region plan to check
079   * @return true if the conditional is violated
080   */
081  boolean isViolating(RegionPlan regionPlan) {
082    if (regionPlan == null) {
083      return false;
084    }
085    int destinationServerIdx = cluster.serversToIndex.get(regionPlan.getDestination().getAddress());
086
087    // Check Server
088    int[] destinationRegionIndices = cluster.regionsPerServer[destinationServerIdx];
089    Set<RegionInfo> serverRegions =
090      getRegionsFromIndex(destinationServerIdx, cluster.regionsPerServer);
091    for (int regionIdx : destinationRegionIndices) {
092      serverRegions.add(cluster.regions[regionIdx]);
093    }
094    if (isViolatingServer(regionPlan, serverRegions)) {
095      return true;
096    }
097
098    if (getValidationLevel() == ValidationLevel.SERVER) {
099      return false;
100    }
101
102    // Check Host
103    int hostIdx = cluster.serverIndexToHostIndex[destinationServerIdx];
104    Set<RegionInfo> hostRegions = getRegionsFromIndex(hostIdx, cluster.regionsPerHost);
105    if (isViolatingHost(regionPlan, hostRegions)) {
106      return true;
107    }
108
109    if (getValidationLevel() == ValidationLevel.SERVER_HOST) {
110      return false;
111    }
112
113    // Check Rack
114    int rackIdx = cluster.serverIndexToRackIndex[destinationServerIdx];
115    Set<RegionInfo> rackRegions = getRegionsFromIndex(rackIdx, cluster.regionsPerRack);
116    if (isViolatingRack(regionPlan, rackRegions)) {
117      return true;
118    }
119
120    return false;
121  }
122
123  abstract boolean isViolatingServer(RegionPlan regionPlan, Set<RegionInfo> destinationRegions);
124
125  boolean isViolatingHost(RegionPlan regionPlan, Set<RegionInfo> destinationRegions) {
126    return false;
127  }
128
129  boolean isViolatingRack(RegionPlan regionPlan, Set<RegionInfo> destinationRegions) {
130    return false;
131  }
132
133  private Set<RegionInfo> getRegionsFromIndex(int index, int[][] regionsPerIndex) {
134    int[] regionIndices = regionsPerIndex[index];
135    if (regionIndices == null) {
136      return Collections.emptySet();
137    }
138    return Arrays.stream(regionIndices).mapToObj(idx -> cluster.regions[idx])
139      .collect(Collectors.toSet());
140  }
141}