hbase-server/src/test/java/org/apache/hadoop/hbase/client/TestMetaRegionLocationCache.java

   1 /*
   2  * Licensed to the Apache Software Foundation (ASF) under one
   3  * or more contributor license agreements.  See the NOTICE file
   4  * distributed with this work for additional information
   5  * regarding copyright ownership.  The ASF licenses this file
   6  * to you under the Apache License, Version 2.0 (the
   7  * "License"); you may not use this file except in compliance
   8  * with the License.  You may obtain a copy of the License at
   9  *
  10  *     http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing, software
  13  * distributed under the License is distributed on an "AS IS" BASIS,
  14  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  * See the License for the specific language governing permissions and
  16  * limitations under the License.
  17  */
  18 package org.apache.hadoop.hbase.client;
  19
  20 import static org.junit.Assert.assertEquals;
  21 import static org.junit.Assert.assertFalse;
  22 import static org.junit.Assert.assertTrue;
  23
  24 import java.util.ArrayList;
  25 import java.util.Collections;
  26 import java.util.List;
  27 import org.apache.hadoop.conf.Configuration;
  28 import org.apache.hadoop.hbase.HBaseClassTestRule;
  29 import org.apache.hadoop.hbase.HBaseTestingUtil;
  30 import org.apache.hadoop.hbase.HConstants;
  31 import org.apache.hadoop.hbase.HRegionLocation;
  32 import org.apache.hadoop.hbase.MetaRegionLocationCache;
  33 import org.apache.hadoop.hbase.MultithreadedTestUtil;
  34 import org.apache.hadoop.hbase.ServerName;
  35 import org.apache.hadoop.hbase.TableName;
  36 import org.apache.hadoop.hbase.master.HMaster;
  37 import org.apache.hadoop.hbase.master.RegionState;
  38 import org.apache.hadoop.hbase.testclassification.MasterTests;
  39 import org.apache.hadoop.hbase.testclassification.SmallTests;
  40 import org.apache.hadoop.hbase.util.JVMClusterUtil;
  41 import org.apache.hadoop.hbase.zookeeper.MetaTableLocator;
  42 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
  43 import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
  44 import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
  45 import org.junit.AfterClass;
  46 import org.junit.BeforeClass;
  47 import org.junit.ClassRule;
  48 import org.junit.Test;
  49 import org.junit.experimental.categories.Category;
  50
  51 import org.apache.hbase.thirdparty.com.google.common.io.Closeables;
  52
  53 @Category({SmallTests.class, MasterTests.class })
  54 public class TestMetaRegionLocationCache {
  55   @ClassRule
  56   public static final HBaseClassTestRule CLASS_RULE =
  57       HBaseClassTestRule.forClass(TestMetaRegionLocationCache.class);
  58
  59   private static final HBaseTestingUtil TEST_UTIL = new HBaseTestingUtil();
  60   private static ConnectionRegistry REGISTRY;
  61
  62   @BeforeClass
  63   public static void setUp() throws Exception {
  64     TEST_UTIL.startMiniCluster(3);
  65     HBaseTestingUtil.setReplicas(TEST_UTIL.getAdmin(), TableName.META_TABLE_NAME, 3);
  66     REGISTRY = ConnectionRegistryFactory.getRegistry(TEST_UTIL.getConfiguration());
  67     RegionReplicaTestHelper.waitUntilAllMetaReplicasAreReady(TEST_UTIL, REGISTRY);
  68     TEST_UTIL.getAdmin().balancerSwitch(false, true);
  69   }
  70
  71   @AfterClass
  72   public static void cleanUp() throws Exception {
  73     Closeables.close(REGISTRY, true);
  74     TEST_UTIL.shutdownMiniCluster();
  75   }
  76
  77   private List<HRegionLocation> getCurrentMetaLocations(ZKWatcher zk) throws Exception {
  78     List<HRegionLocation> result = new ArrayList<>();
  79     for (String znode: zk.getMetaReplicaNodes()) {
  80       String path = ZNodePaths.joinZNode(zk.getZNodePaths().baseZNode, znode);
  81       int replicaId = zk.getZNodePaths().getMetaReplicaIdFromPath(path);
  82       RegionState state = MetaTableLocator.getMetaRegionState(zk, replicaId);
  83       result.add(new HRegionLocation(state.getRegion(), state.getServerName()));
  84     }
  85     return result;
  86   }
  87
  88   // Verifies that the cached meta locations in the given master are in sync with what is in ZK.
  89   private void verifyCachedMetaLocations(HMaster master) throws Exception {
  90     // Wait until initial meta locations are loaded.
  91     int retries = 0;
  92     while (master.getMetaRegionLocationCache().getMetaRegionLocations().isEmpty()) {
  93       Thread.sleep(1000);
  94       if (++retries == 10) {
  95         break;
  96       }
  97     }
  98     ZKWatcher zk = master.getZooKeeper();
  99     List<String> metaZnodes = zk.getMetaReplicaNodes();
 100     // Wait till all replicas available.
 101     retries = 0;
 102     while (master.getMetaRegionLocationCache().getMetaRegionLocations().size() != metaZnodes
 103       .size()) {
 104       Thread.sleep(1000);
 105       if (++retries == 10) {
 106         break;
 107       }
 108     }
 109     List<HRegionLocation> metaHRLs = master.getMetaRegionLocationCache().getMetaRegionLocations();
 110     assertFalse(metaHRLs.isEmpty());
 111     assertEquals(metaZnodes.size(), metaHRLs.size());
 112     List<HRegionLocation> actualHRLs = getCurrentMetaLocations(zk);
 113     Collections.sort(metaHRLs);
 114     Collections.sort(actualHRLs);
 115     assertEquals(actualHRLs, metaHRLs);
 116   }
 117
 118   @Test
 119   public void testInitialMetaLocations() throws Exception {
 120     verifyCachedMetaLocations(TEST_UTIL.getMiniHBaseCluster().getMaster());
 121   }
 122
 123   @Test
 124   public void testStandByMetaLocations() throws Exception {
 125     HMaster standBy = TEST_UTIL.getMiniHBaseCluster().startMaster().getMaster();
 126     verifyCachedMetaLocations(standBy);
 127   }
 128
 129   /*
 130    * Shuffles the meta region replicas around the cluster and makes sure the cache is not stale.
 131    */
 132   @Test public void testMetaLocationsChange() throws Exception {
 133     List<HRegionLocation> currentMetaLocs =
 134         getCurrentMetaLocations(TEST_UTIL.getMiniHBaseCluster().getMaster().getZooKeeper());
 135     // Move these replicas to random servers.
 136     for (HRegionLocation location: currentMetaLocs) {
 137       RegionReplicaTestHelper.moveRegion(TEST_UTIL, location);
 138     }
 139     RegionReplicaTestHelper.waitUntilAllMetaReplicasAreReady(TEST_UTIL, REGISTRY);
 140     for (JVMClusterUtil.MasterThread masterThread:
 141         TEST_UTIL.getMiniHBaseCluster().getMasterThreads()) {
 142       verifyCachedMetaLocations(masterThread.getMaster());
 143     }
 144   }
 145
 146   /**
 147    * Tests MetaRegionLocationCache's init procedure to make sure that it correctly watches the base
 148    * znode for notifications.
 149    */
 150   @Test public void testMetaRegionLocationCache() throws Exception {
 151     final String parentZnodeName = "/randomznodename";
 152     Configuration conf = new Configuration(TEST_UTIL.getConfiguration());
 153     conf.set(HConstants.ZOOKEEPER_ZNODE_PARENT, parentZnodeName);
 154     ServerName sn = ServerName.valueOf("localhost", 1234, 5678);
 155     try (ZKWatcher zkWatcher = new ZKWatcher(conf, null, null, true)) {
 156       // A thread that repeatedly creates and drops an unrelated child znode. This is to simulate
 157       // some ZK activity in the background.
 158       MultithreadedTestUtil.TestContext ctx = new MultithreadedTestUtil.TestContext(conf);
 159       ctx.addThread(new MultithreadedTestUtil.RepeatingTestThread(ctx) {
 160         @Override 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 }