HDFS-5076. Add MXBean methods to query NN's transaction information and JournalNode's journal status. Contributed by Jing Zhao.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1514422 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -288,6 +288,9 @@ Release 2.1.1-beta - UNRELEASED
 
     HDFS-4763 Add script changes/utility for starting NFS gateway (brandonli)
 
+    HDFS-5076 Add MXBean methods to query NN's transaction information and 
+    JournalNode's journal status. (jing9)
+
   IMPROVEMENTS
 
     HDFS-4513. Clarify in the WebHDFS REST API that all JSON respsonses may

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNode.java

@@ -18,8 +18,10 @@
 package org.apache.hadoop.hdfs.qjournal.server;
 
 import java.io.File;
+import java.io.FileFilter;
 import java.io.IOException;
 import java.net.InetSocketAddress;
+import java.util.HashMap;
 import java.util.Map;
 
 import org.apache.commons.logging.Log;
@@ -34,11 +36,13 @@ import org.apache.hadoop.hdfs.server.common.StorageErrorReporter;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
 import org.apache.hadoop.metrics2.source.JvmMetrics;
+import org.apache.hadoop.metrics2.util.MBeans;
 import org.apache.hadoop.security.SecurityUtil;
 import org.apache.hadoop.util.DiskChecker;
 import org.apache.hadoop.util.StringUtils;
 import org.apache.hadoop.util.Tool;
 import org.apache.hadoop.util.ToolRunner;
+import org.mortbay.util.ajax.JSON;
 
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Maps;
@@ -51,7 +55,7 @@ import com.google.common.collect.Maps;
  * in the quorum protocol.
  */
 @InterfaceAudience.Private
-public class JournalNode implements Tool, Configurable {
+public class JournalNode implements Tool, Configurable, JournalNodeMXBean {
   public static final Log LOG = LogFactory.getLog(JournalNode.class);
   private Configuration conf;
   private JournalNodeRpcServer rpcServer;
@@ -128,6 +132,8 @@ public class JournalNode implements Tool, Configurable {
     SecurityUtil.login(conf, DFSConfigKeys.DFS_JOURNALNODE_KEYTAB_FILE_KEY,
         DFSConfigKeys.DFS_JOURNALNODE_USER_NAME_KEY, socAddr.getHostName());
     
+    registerJNMXBean();
+    
     httpServer = new JournalNodeHttpServer(conf, this);
     httpServer.start();
 
@@ -208,6 +214,50 @@ public class JournalNode implements Tool, Configurable {
     return new File(new File(dir), jid);
   }
 
+  @Override // JournalNodeMXBean
+  public String getJournalsStatus() {
+    // jid:{Formatted:True/False}
+    Map<String, Map<String, String>> status = 
+        new HashMap<String, Map<String, String>>();
+    synchronized (this) {
+      for (Map.Entry<String, Journal> entry : journalsById.entrySet()) {
+        Map<String, String> jMap = new HashMap<String, String>();
+        jMap.put("Formatted", Boolean.toString(entry.getValue().isFormatted()));
+        status.put(entry.getKey(), jMap);
+      }
+    }
+    
+    // It is possible that some journals have been formatted before, while the 
+    // corresponding journals are not in journalsById yet (because of restarting
+    // JN, e.g.). For simplicity, let's just assume a journal is formatted if
+    // there is a directory for it. We can also call analyzeStorage method for
+    // these directories if necessary.
+    // Also note that we do not need to check localDir here since
+    // validateAndCreateJournalDir has been called before we register the
+    // MXBean.
+    File[] journalDirs = localDir.listFiles(new FileFilter() {
+      @Override
+      public boolean accept(File file) {
+        return file.isDirectory();
+      }
+    });
+    for (File journalDir : journalDirs) {
+      String jid = journalDir.getName();
+      if (!status.containsKey(jid)) {
+        Map<String, String> jMap = new HashMap<String, String>();
+        jMap.put("Formatted", "true");
+        status.put(jid, jMap);
+      }
+    }
+    return JSON.toString(status);
+  }
+  
+  /**
+   * Register JournalNodeMXBean
+   */
+  private void registerJNMXBean() {
+    MBeans.register("JournalNode", "JournalNodeInfo", this);
+  }
   
   private class ErrorReporter implements StorageErrorReporter {
     @Override

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/server/JournalNodeMXBean.java

@@ -0,0 +1,36 @@
+/**
+ * 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.qjournal.server;
+
+import org.apache.hadoop.classification.InterfaceAudience;
+import org.apache.hadoop.classification.InterfaceStability;
+
+/**
+ * This is the JMX management interface for JournalNode information
+ */
+@InterfaceAudience.Public
+@InterfaceStability.Evolving
+public interface JournalNodeMXBean {
+  
+  /**
+   * Get status information (e.g., whether formatted) of JournalNode's journals.
+   * 
+   * @return A string presenting status for each journal
+   */
+  public String getJournalsStatus();
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSNamesystem.java

@@ -6364,6 +6364,16 @@ public class FSNamesystem implements Namesystem, FSClusterStats,
     return JSON.toString(jasList);
   }
 
+  @Override // NameNodeMxBean
+  public String getJournalTransactionInfo() {
+    Map<String, String> txnIdMap = new HashMap<String, String>();
+    txnIdMap.put("LastAppliedOrWrittenTxId",
+        Long.toString(this.getFSImage().getLastAppliedOrWrittenTxId()));
+    txnIdMap.put("MostRecentCheckpointTxId",
+        Long.toString(this.getFSImage().getMostRecentCheckpointTxId()));
+    return JSON.toString(txnIdMap);
+  }
+  
   @Override  // NameNodeMXBean
   public String getNNStarted() {
     return getStartTime().toString();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/NameNodeMXBean.java

@@ -188,6 +188,12 @@ public interface NameNodeMXBean {
    * @return the name journal status information, as a JSON string.
    */
   public String getNameJournalStatus();
+  
+  /**
+   * Get information about the transaction ID, including the last applied 
+   * transaction ID and the most recent checkpoint's transaction ID
+   */
+  public String getJournalTransactionInfo();
 
   /**
    * Gets the NN start time

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/qjournal/server/TestJournalNodeMXBean.java

@@ -0,0 +1,107 @@
+/**
+ * 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.qjournal.server;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+
+import java.io.IOException;
+import java.lang.management.ManagementFactory;
+import java.util.HashMap;
+import java.util.Map;
+
+import javax.management.MBeanServer;
+import javax.management.ObjectName;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hdfs.qjournal.MiniJournalCluster;
+import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+import org.mortbay.util.ajax.JSON;
+
+/**
+ * Test {@link JournalNodeMXBean}
+ */
+public class TestJournalNodeMXBean {
+  
+  private static final String NAMESERVICE = "ns1";
+  private static final int NUM_JN = 1;
+  
+  private MiniJournalCluster jCluster;
+  private JournalNode jn;
+  
+  @Before
+  public void setup() throws IOException {
+    // start 1 journal node
+    jCluster = new MiniJournalCluster.Builder(new Configuration()).format(true)
+        .numJournalNodes(NUM_JN).build();
+    jn = jCluster.getJournalNode(0);
+  }
+  
+  @After
+  public void cleanup() throws IOException {
+    if (jCluster != null) {
+      jCluster.shutdown();
+    }
+  }
+  
+  @Test
+  public void testJournalNodeMXBean() throws Exception {
+    // we have not formatted the journals yet, and the journal status in jmx
+    // should be empty since journal objects are created lazily
+    MBeanServer mbs = ManagementFactory.getPlatformMBeanServer();
+    ObjectName mxbeanName = new ObjectName(
+        "Hadoop:service=JournalNode,name=JournalNodeInfo");
+
+    // getJournalsStatus
+    String journalStatus = (String) mbs.getAttribute(mxbeanName,
+        "JournalsStatus");
+    assertEquals(jn.getJournalsStatus(), journalStatus);
+    assertFalse(journalStatus.contains(NAMESERVICE));
+
+    // format the journal ns1
+    final NamespaceInfo FAKE_NSINFO = new NamespaceInfo(12345, "mycluster",
+        "my-bp", 0L);
+    jn.getOrCreateJournal(NAMESERVICE).format(FAKE_NSINFO);
+
+    // check again after format
+    // getJournalsStatus
+    journalStatus = (String) mbs.getAttribute(mxbeanName, "JournalsStatus");
+    assertEquals(jn.getJournalsStatus(), journalStatus);
+    Map<String, Map<String, String>> jMap = new HashMap<String, Map<String, String>>();
+    Map<String, String> infoMap = new HashMap<String, String>();
+    infoMap.put("Formatted", "true");
+    jMap.put(NAMESERVICE, infoMap);
+    assertEquals(JSON.toString(jMap), journalStatus);
+    
+    // restart journal node without formatting
+    jCluster = new MiniJournalCluster.Builder(new Configuration()).format(false)
+        .numJournalNodes(NUM_JN).build();
+    jn = jCluster.getJournalNode(0);
+    // re-check 
+    journalStatus = (String) mbs.getAttribute(mxbeanName, "JournalsStatus");
+    assertEquals(jn.getJournalsStatus(), journalStatus);
+    jMap = new HashMap<String, Map<String, String>>();
+    infoMap = new HashMap<String, String>();
+    infoMap.put("Formatted", "true");
+    jMap.put(NAMESERVICE, infoMap);
+    assertEquals(JSON.toString(jMap), journalStatus);
+  }
+}

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

@@ -120,6 +120,11 @@ public class TestNameNodeMXBean {
       String nameJournalStatus = (String) (mbs.getAttribute(mxbeanName,
           "NameJournalStatus"));
       assertEquals("Bad value for NameJournalStatus", fsn.getNameJournalStatus(), nameJournalStatus);
+      // get attribute JournalTransactionInfo
+      String journalTxnInfo = (String) mbs.getAttribute(mxbeanName,
+          "JournalTransactionInfo");
+      assertEquals("Bad value for NameTxnIds", fsn.getJournalTransactionInfo(),
+          journalTxnInfo);
       // get attribute "NNStarted"
       String nnStarted = (String) mbs.getAttribute(mxbeanName, "NNStarted");
       assertEquals("Bad value for NNStarted", fsn.getNNStarted(), nnStarted);