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