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.client;
019
020import static org.junit.jupiter.api.Assertions.assertEquals;
021import static org.junit.jupiter.api.Assertions.assertFalse;
022import static org.junit.jupiter.api.Assertions.assertTrue;
023
024import java.util.ArrayList;
025import java.util.Collections;
026import java.util.List;
027import org.apache.hadoop.conf.Configuration;
028import org.apache.hadoop.hbase.HBaseTestingUtil;
029import org.apache.hadoop.hbase.HConstants;
030import org.apache.hadoop.hbase.HRegionLocation;
031import org.apache.hadoop.hbase.MetaRegionLocationCache;
032import org.apache.hadoop.hbase.MultithreadedTestUtil;
033import org.apache.hadoop.hbase.ServerName;
034import org.apache.hadoop.hbase.TableName;
035import org.apache.hadoop.hbase.master.HMaster;
036import org.apache.hadoop.hbase.master.RegionState;
037import org.apache.hadoop.hbase.security.User;
038import org.apache.hadoop.hbase.testclassification.MasterTests;
039import org.apache.hadoop.hbase.testclassification.SmallTests;
040import org.apache.hadoop.hbase.util.JVMClusterUtil;
041import org.apache.hadoop.hbase.zookeeper.MetaTableLocator;
042import org.apache.hadoop.hbase.zookeeper.ZKUtil;
043import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
044import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
045import org.junit.jupiter.api.AfterAll;
046import org.junit.jupiter.api.BeforeAll;
047import org.junit.jupiter.api.Tag;
048import org.junit.jupiter.api.Test;
049
050import org.apache.hbase.thirdparty.com.google.common.io.Closeables;
051
052@Tag(SmallTests.TAG)
053@Tag(MasterTests.TAG)
054public class TestMetaRegionLocationCache {
055  private static final HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
056  private static ConnectionRegistry REGISTRY;
057
058  @BeforeAll
059  public static void setUp() throws Exception {
060    TEST_UTIL.startMiniCluster(3);
061    HBaseTestingUtil.setReplicas(TEST_UTIL.getAdmin(), TableName.META_TABLE_NAME, 3);
062    REGISTRY = ConnectionRegistryFactory.create(TEST_UTIL.getConfiguration(), User.getCurrent());
063    RegionReplicaTestHelper.waitUntilAllMetaReplicasAreReady(TEST_UTIL, REGISTRY);
064    TEST_UTIL.getAdmin().balancerSwitch(false, true);
065  }
066
067  @AfterAll
068  public static void cleanUp() throws Exception {
069    Closeables.close(REGISTRY, true);
070    TEST_UTIL.shutdownMiniCluster();
071  }
072
073  private List<HRegionLocation> getCurrentMetaLocations(ZKWatcher zk) throws Exception {
074    List<HRegionLocation> result = new ArrayList<>();
075    for (String znode : zk.getMetaReplicaNodes()) {
076      String path = ZNodePaths.joinZNode(zk.getZNodePaths().baseZNode, znode);
077      int replicaId = zk.getZNodePaths().getMetaReplicaIdFromPath(path);
078      RegionState state = MetaTableLocator.getMetaRegionState(zk, replicaId);
079      result.add(new HRegionLocation(state.getRegion(), state.getServerName()));
080    }
081    return result;
082  }
083
084  // Verifies that the cached meta locations in the given master are in sync with what is in ZK.
085  private void verifyCachedMetaLocations(HMaster master) throws Exception {
086    // Wait until initial meta locations are loaded.
087    int retries = 0;
088    while (master.getMetaRegionLocationCache().getMetaRegionLocations().isEmpty()) {
089      Thread.sleep(1000);
090      if (++retries == 10) {
091        break;
092      }
093    }
094    ZKWatcher zk = master.getZooKeeper();
095    List<String> metaZnodes = zk.getMetaReplicaNodes();
096    // Wait till all replicas available.
097    retries = 0;
098    while (
099      master.getMetaRegionLocationCache().getMetaRegionLocations().size() != metaZnodes.size()
100    ) {
101      Thread.sleep(1000);
102      if (++retries == 10) {
103        break;
104      }
105    }
106    List<HRegionLocation> metaHRLs = master.getMetaRegionLocationCache().getMetaRegionLocations();
107    assertFalse(metaHRLs.isEmpty());
108    assertEquals(metaZnodes.size(), metaHRLs.size());
109    List<HRegionLocation> actualHRLs = getCurrentMetaLocations(zk);
110    Collections.sort(metaHRLs);
111    Collections.sort(actualHRLs);
112    assertEquals(actualHRLs, metaHRLs);
113  }
114
115  @Test
116  public void testInitialMetaLocations() throws Exception {
117    verifyCachedMetaLocations(TEST_UTIL.getMiniHBaseCluster().getMaster());
118  }
119
120  @Test
121  public void testStandByMetaLocations() throws Exception {
122    HMaster standBy = TEST_UTIL.getMiniHBaseCluster().startMaster().getMaster();
123    verifyCachedMetaLocations(standBy);
124  }
125
126  /*
127   * Shuffles the meta region replicas around the cluster and makes sure the cache is not stale.
128   */
129  @Test
130  public void testMetaLocationsChange() throws Exception {
131    List<HRegionLocation> currentMetaLocs =
132      getCurrentMetaLocations(TEST_UTIL.getMiniHBaseCluster().getMaster().getZooKeeper());
133    // Move these replicas to random servers.
134    for (HRegionLocation location : currentMetaLocs) {
135      RegionReplicaTestHelper.moveRegion(TEST_UTIL, location);
136    }
137    RegionReplicaTestHelper.waitUntilAllMetaReplicasAreReady(TEST_UTIL, REGISTRY);
138    for (JVMClusterUtil.MasterThread masterThread : TEST_UTIL.getMiniHBaseCluster()
139      .getMasterThreads()) {
140      verifyCachedMetaLocations(masterThread.getMaster());
141    }
142  }
143
144  /**
145   * Tests MetaRegionLocationCache's init procedure to make sure that it correctly watches the base
146   * znode for notifications.
147   */
148  @Test
149  public void testMetaRegionLocationCache() throws Exception {
150    final String parentZnodeName = "/randomznodename";
151    Configuration conf = new Configuration(TEST_UTIL.getConfiguration());
152    conf.set(HConstants.ZOOKEEPER_ZNODE_PARENT, parentZnodeName);
153    ServerName sn = ServerName.valueOf("localhost", 1234, 5678);
154    try (ZKWatcher zkWatcher = new ZKWatcher(conf, null, null, true)) {
155      // A thread that repeatedly creates and drops an unrelated child znode. This is to simulate
156      // some ZK activity in the background.
157      MultithreadedTestUtil.TestContext ctx = new MultithreadedTestUtil.TestContext(conf);
158      ctx.addThread(new MultithreadedTestUtil.RepeatingTestThread(ctx) {
159        @Override
160        public void doAnAction() throws Exception {
161          final String testZnode = parentZnodeName + "/child";
162          ZKUtil.createNodeIfNotExistsAndWatch(zkWatcher, testZnode, testZnode.getBytes());
163          ZKUtil.deleteNode(zkWatcher, testZnode);
164        }
165      });
166      ctx.startThreads();
167      try {
168        MetaRegionLocationCache metaCache = new MetaRegionLocationCache(zkWatcher);
169        // meta znodes do not exist at this point, cache should be empty.
170        assertTrue(metaCache.getMetaRegionLocations().isEmpty());
171        // Set the meta locations for a random meta replicas, simulating an active hmaster meta
172        // assignment.
173        for (int i = 0; i < 3; i++) {
174          // Updates the meta znodes.
175          MetaTableLocator.setMetaLocation(zkWatcher, sn, i, RegionState.State.OPEN);
176        }
177        // Wait until the meta cache is populated.
178        int iters = 0;
179        while (iters++ < 10) {
180          if (metaCache.getMetaRegionLocations().size() == 3) {
181            break;
182          }
183          Thread.sleep(1000);
184        }
185        List<HRegionLocation> metaLocations = metaCache.getMetaRegionLocations();
186        assertEquals(3, metaLocations.size());
187        for (HRegionLocation location : metaLocations) {
188          assertEquals(sn, location.getServerName());
189        }
190      } finally {
191        // clean up.
192        ctx.stop();
193        ZKUtil.deleteChildrenRecursively(zkWatcher, parentZnodeName);
194      }
195    }
196  }
197}