HDFS-2623. Add test case for hot standby capability. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-1623@1209256 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-1623.txt

@@ -37,3 +37,5 @@ HDFS-2616. Change DatanodeProtocol#sendHeartbeat() to return HeartbeatResponse.
 HDFS-2622. Fix TestDFSUpgrade in HA branch. (todd)
 
 HDFS-2612. Handle refreshNameNodes in federated HA clusters (todd)
+
+HDFS-2623. Add test case for hot standby capability (todd)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/AppendTestUtil.java

@@ -109,7 +109,7 @@ static void write(OutputStream out, int offset, int length) throws IOException {
     out.write(bytes);
   }
   
-  static void check(FileSystem fs, Path p, long length) throws IOException {
+  public static void check(FileSystem fs, Path p, long length) throws IOException {
     int i = -1;
     try {
       final FileStatus status = fs.getFileStatus(p);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestDFSClientFailover.java

@@ -82,13 +82,28 @@ public void testDfsClientFailover() throws IOException, URISyntaxException {
     AppendTestUtil.write(out2, 0, FILE_LENGTH_TO_VERIFY);
     out1.close();
     out2.close();
+        
+    FileSystem fs = configureFailoverFs(cluster, conf);
     
+    AppendTestUtil.check(fs, TEST_FILE, FILE_LENGTH_TO_VERIFY);
+    cluster.getNameNode(0).stop();
+    AppendTestUtil.check(fs, TEST_FILE, FILE_LENGTH_TO_VERIFY);
+    
+    fs.close();
+  }
+
+  public static FileSystem configureFailoverFs(MiniDFSCluster cluster, Configuration conf)
+  throws IOException, URISyntaxException {
+    InetSocketAddress nnAddr1 = cluster.getNameNode(0).getNameNodeAddress();
+    InetSocketAddress nnAddr2 = cluster.getNameNode(1).getNameNodeAddress();
+
     String nsId = "nameserviceId1";
     
     final String logicalNameNodeId = "ha-nn-uri";
     String nameNodeId1 = "nn1";
     String nameNodeId2 = "nn2";
     
+    conf = new Configuration(conf);
     String address1 = "hdfs://" + nnAddr1.getHostName() + ":" + nnAddr1.getPort();
     String address2 = "hdfs://" + nnAddr2.getHostName() + ":" + nnAddr2.getPort();
     conf.set(DFSUtil.addKeySuffixes(DFS_NAMENODE_RPC_ADDRESS_KEY,
@@ -103,12 +118,7 @@ public void testDfsClientFailover() throws IOException, URISyntaxException {
         ConfiguredFailoverProxyProvider.class.getName());
     
     FileSystem fs = FileSystem.get(new URI("hdfs://" + logicalNameNodeId), conf);
-    
+    return fs;
-    AppendTestUtil.check(fs, TEST_FILE, FILE_LENGTH_TO_VERIFY);
-    cluster.getNameNode(0).stop();
-    AppendTestUtil.check(fs, TEST_FILE, FILE_LENGTH_TO_VERIFY);
-    
-    fs.close();
   }
 
-}
+}

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestEditLogTailer.java

@@ -33,6 +33,7 @@
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
 import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
 import org.apache.log4j.Level;
+import org.junit.Assert;
 import org.junit.Test;
 
 public class TestEditLogTailer {
@@ -99,12 +100,13 @@ private static String getDirPath(int suffix) {
     return DIR_PREFIX + suffix;
   }
   
-  private static void waitForStandbyToCatchUp(NameNode active,
+  static void waitForStandbyToCatchUp(NameNode active,
       NameNode standby) throws InterruptedException, IOException {
     
     long activeTxId = active.getNamesystem().getFSImage().getEditLog()
       .getLastWrittenTxId();
     
+    // TODO: we should really just ask for a log roll here
     doSaveNamespace(active);
     
     long start = System.currentTimeMillis();
@@ -112,10 +114,13 @@ private static void waitForStandbyToCatchUp(NameNode active,
       long nn2HighestTxId = standby.getNamesystem().getFSImage()
         .getLastAppliedTxId();
       if (nn2HighestTxId >= activeTxId) {
-        break;
+        return;
       }
       Thread.sleep(SLEEP_TIME);
     }
+    Assert.fail("Standby did not catch up to txid " + activeTxId +
+        " (currently at " +
+        standby.getNamesystem().getFSImage().getLastAppliedTxId() + ")");
   }
   
   private static void doSaveNamespace(NameNode nn)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestStandbyIsHot.java

@@ -0,0 +1,110 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.hadoop.hdfs.server.namenode.ha;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.util.concurrent.TimeoutException;
+
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.hdfs.AppendTestUtil;
+import org.apache.hadoop.hdfs.DFSTestUtil;
+import org.apache.hadoop.hdfs.MiniDFSCluster;
+import org.apache.hadoop.hdfs.MiniDFSNNTopology;
+import org.apache.hadoop.hdfs.TestDFSClientFailover;
+import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
+import org.apache.hadoop.hdfs.server.namenode.NameNode;
+import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
+import org.apache.hadoop.test.GenericTestUtils;
+import org.junit.Test;
+
+import com.google.common.base.Supplier;
+
+/**
+ * The hotornot.com of unit tests: makes sure that the standby not only
+ * has namespace information, but also has the correct block reports, etc.
+ */
+public class TestStandbyIsHot {
+  protected static final Log LOG = LogFactory.getLog(
+      TestStandbyIsHot.class);
+  private static final String TEST_FILE_DATA = "hello highly available world";
+  private static final String TEST_FILE = "/testStandbyIsHot";
+  private static final Path TEST_FILE_PATH = new Path(TEST_FILE);
+
+  @Test
+  public void testStandbyIsHot() throws Exception {
+    Configuration conf = new Configuration();
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
+      .nnTopology(MiniDFSNNTopology.simpleHATopology())
+      .numDataNodes(3)
+      .build();
+    try {
+      cluster.waitActive();
+      cluster.transitionToActive(0);
+      
+      NameNode nn1 = cluster.getNameNode(0);
+      NameNode nn2 = cluster.getNameNode(1);
+      nn2.getNamesystem().getEditLogTailer().setSleepTime(250);
+      nn2.getNamesystem().getEditLogTailer().interrupt();
+      
+      FileSystem fs = TestDFSClientFailover.configureFailoverFs(cluster, conf);
+      
+      Thread.sleep(1000);
+      System.err.println("==================================");
+      DFSTestUtil.writeFile(fs, TEST_FILE_PATH, TEST_FILE_DATA);
+      // Have to force an edit log roll so that the standby catches up
+      nn1.getRpcServer().rollEditLog();
+      System.err.println("==================================");
+
+      waitForBlockLocations(nn2, TEST_FILE, 3);
+      
+      nn1.stop();
+      cluster.transitionToActive(1);
+
+      assertEquals(TEST_FILE_DATA, DFSTestUtil.readFile(fs, TEST_FILE_PATH));
+      
+    } finally {
+      cluster.shutdown();
+    }
+  }
+
+  private void waitForBlockLocations(final NameNode nn,
+      final String path, final int expectedReplicas)
+      throws Exception {
+    GenericTestUtils.waitFor(new Supplier<Boolean>() {
+      
+      @Override
+      public Boolean get() {
+        try {
+          LocatedBlocks locs = NameNodeAdapter.getBlockLocations(nn, path, 0, 1000);
+          LOG.info("Got locs: " + locs);
+          return locs.getLastLocatedBlock().getLocations().length == expectedReplicas;
+        } catch (IOException e) {
+          LOG.warn("No block locations yet: " + e.getMessage());
+          return false;
+        }
+      }
+    }, 500, 10000);
+    
+  }
+}