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 static org.apache.hadoop.hbase.master.balancer.CandidateGeneratorTestUtil.isTableIsolated;
021import static org.apache.hadoop.hbase.master.balancer.CandidateGeneratorTestUtil.runBalancerToExhaustion;
022
023import java.util.ArrayList;
024import java.util.HashMap;
025import java.util.List;
026import java.util.Map;
027import java.util.Set;
028import org.apache.hadoop.conf.Configuration;
029import org.apache.hadoop.hbase.HBaseClassTestRule;
030import org.apache.hadoop.hbase.ServerName;
031import org.apache.hadoop.hbase.TableName;
032import org.apache.hadoop.hbase.client.RegionInfo;
033import org.apache.hadoop.hbase.client.RegionInfoBuilder;
034import org.apache.hadoop.hbase.testclassification.MasterTests;
035import org.apache.hadoop.hbase.testclassification.MediumTests;
036import org.junit.BeforeClass;
037import org.junit.ClassRule;
038import org.junit.Test;
039import org.junit.experimental.categories.Category;
040import org.slf4j.Logger;
041import org.slf4j.LoggerFactory;
042
043/**
044 * If your minCostNeedsBalance is set too low, then the balancer should still eventually stop making
045 * moves as further cost improvements become impossible, and balancer plan calculation becomes
046 * wasteful. This test ensures that the balancer will not get stuck in a loop of continuously moving
047 * regions.
048 */
049@Category({ MasterTests.class, MediumTests.class })
050public class TestUnattainableBalancerCostGoal {
051
052  @ClassRule
053  public static final HBaseClassTestRule CLASS_RULE =
054    HBaseClassTestRule.forClass(TestUnattainableBalancerCostGoal.class);
055
056  private static final Logger LOG = LoggerFactory.getLogger(TestUnattainableBalancerCostGoal.class);
057
058  private static final TableName SYSTEM_TABLE_NAME = TableName.valueOf("hbase:system");
059  private static final TableName NON_SYSTEM_TABLE_NAME = TableName.valueOf("userTable");
060
061  private static final int NUM_SERVERS = 10;
062  private static final int NUM_REGIONS = 1000;
063  private static final float UNACHIEVABLE_COST_GOAL = 0.01f;
064
065  private static final ServerName[] servers = new ServerName[NUM_SERVERS];
066  private static final Map<ServerName, List<RegionInfo>> serverToRegions = new HashMap<>();
067
068  @BeforeClass
069  public static void setup() {
070    // Initialize servers
071    for (int i = 0; i < NUM_SERVERS; i++) {
072      servers[i] = ServerName.valueOf("server" + i, i, System.currentTimeMillis());
073    }
074
075    // Create regions
076    List<RegionInfo> allRegions = new ArrayList<>();
077    for (int i = 0; i < NUM_REGIONS; i++) {
078      TableName tableName = i < 3 ? SYSTEM_TABLE_NAME : NON_SYSTEM_TABLE_NAME;
079      byte[] startKey = new byte[1];
080      startKey[0] = (byte) i;
081      byte[] endKey = new byte[1];
082      endKey[0] = (byte) (i + 1);
083
084      RegionInfo regionInfo =
085        RegionInfoBuilder.newBuilder(tableName).setStartKey(startKey).setEndKey(endKey).build();
086      allRegions.add(regionInfo);
087    }
088
089    // Assign all regions to the first server
090    serverToRegions.put(servers[0], new ArrayList<>(allRegions));
091    for (int i = 1; i < NUM_SERVERS; i++) {
092      serverToRegions.put(servers[i], new ArrayList<>());
093    }
094  }
095
096  @Test
097  public void testSystemTableIsolation() {
098    Configuration conf = new Configuration(false);
099    conf.setBoolean(BalancerConditionals.ISOLATE_SYSTEM_TABLES_KEY, true);
100    runBalancerToExhaustion(conf, serverToRegions, Set.of(this::isSystemTableIsolated),
101      UNACHIEVABLE_COST_GOAL, 10_000, CandidateGeneratorTestUtil.ExhaustionType.NO_MORE_MOVES);
102    LOG.info("Meta table regions are successfully isolated.");
103  }
104
105  private boolean isSystemTableIsolated(BalancerClusterState cluster) {
106    return isTableIsolated(cluster, SYSTEM_TABLE_NAME, "System");
107  }
108}