HDFS-2793. Add an admin command to trigger an edit log roll. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1380982 13f79535-47bb-0310-9956-ffa450edef68

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

@@ -243,6 +243,8 @@ Branch-2 ( Unreleased changes )
 
     HDFS-3150. Add option for clients to contact DNs via hostname. (eli)
 
+    HDFS-2793. Add an admin command to trigger an edit log roll. (todd)
+
   IMPROVEMENTS
 
     HDFS-3390. DFSAdmin should print full stack traces of errors when DEBUG

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DFSClient.java

@@ -1871,6 +1871,20 @@ void saveNamespace() throws AccessControlException, IOException {
     }
   }
 
+  /**
+   * Rolls the edit log on the active NameNode.
+   * @return the txid of the new log segment 
+   *
+   * @see ClientProtocol#rollEdits()
+   */
+  long rollEdits() throws AccessControlException, IOException {
+    try {
+      return namenode.rollEdits();
+    } catch(RemoteException re) {
+      throw re.unwrapRemoteException(AccessControlException.class);
+    }
+  }
+  
   /**
    * enable/disable restore failed storage.
    * 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/DistributedFileSystem.java

@@ -625,6 +625,16 @@ public void saveNamespace() throws AccessControlException, IOException {
     dfs.saveNamespace();
   }
   
+  /**
+   * Rolls the edit log on the active NameNode.
+   * Requires super-user privileges.
+   * @see org.apache.hadoop.hdfs.protocol.ClientProtocol#rollEdits()
+   * @return the transaction ID of the newly created segment
+   */
+  public long rollEdits() throws AccessControlException, IOException {
+    return dfs.rollEdits();
+  }
+
   /**
    * enable/disable/check restoreFaileStorage
    * 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocol/ClientProtocol.java

@@ -667,6 +667,18 @@ public boolean setSafeMode(HdfsConstants.SafeModeAction action)
    */
   public void saveNamespace() throws AccessControlException, IOException;
 
+  
+  /**
+   * Roll the edit log.
+   * Requires superuser privileges.
+   * 
+   * @throws AccessControlException if the superuser privilege is violated
+   * @throws IOException if log roll fails
+   * @return the txid of the new segment
+   */
+  @Idempotent
+  public long rollEdits() throws AccessControlException, IOException;
+
   /**
    * Enable/Disable restore failed storage.
    * <p>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolServerSideTranslatorPB.java

@@ -103,6 +103,8 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ReportBadBlocksResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RestoreFailedStorageRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RestoreFailedStorageResponseProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetBalancerBandwidthRequestProto;
@@ -538,6 +540,20 @@ public SaveNamespaceResponseProto saveNamespace(RpcController controller,
 
   }
   
+  @Override
+  public RollEditsResponseProto rollEdits(RpcController controller,
+      RollEditsRequestProto request) throws ServiceException {
+    try {
+      long txid = server.rollEdits();
+      return RollEditsResponseProto.newBuilder()
+          .setNewSegmentTxId(txid)
+          .build();
+    } catch (IOException e) {
+      throw new ServiceException(e);
+    }
+  }
+
+
   static final RefreshNodesResponseProto VOID_REFRESHNODES_RESPONSE = 
       RefreshNodesResponseProto.newBuilder().build();
 

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/protocolPB/ClientNamenodeProtocolTranslatorPB.java

@@ -87,6 +87,8 @@
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RenewLeaseRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.ReportBadBlocksRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RestoreFailedStorageRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsRequestProto;
+import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.RollEditsResponseProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SaveNamespaceRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetBalancerBandwidthRequestProto;
 import org.apache.hadoop.hdfs.protocol.proto.ClientNamenodeProtocolProtos.SetOwnerRequestProto;
@@ -526,6 +528,17 @@ public void saveNamespace() throws AccessControlException, IOException {
     }
   }
   
+  @Override
+  public long rollEdits() throws AccessControlException, IOException {
+    RollEditsRequestProto req = RollEditsRequestProto.getDefaultInstance();
+    try {
+      RollEditsResponseProto resp = rpcProxy.rollEdits(null, req);
+      return resp.getNewSegmentTxId();
+    } catch (ServiceException se) {
+      throw ProtobufHelper.getRemoteException(se);
+    }
+  }
+
   @Override
   public boolean restoreFailedStorage(String arg) 
       throws AccessControlException, IOException{

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

@@ -4415,6 +4415,7 @@ CheckpointSignature rollEditLog() throws IOException {
     writeLock();
     try {
       checkOperation(OperationCategory.JOURNAL);
+      checkSuperuserPrivilege();
       if (isInSafeMode()) {
         throw new SafeModeException("Log not rolled", safeMode);
       }

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

@@ -710,6 +710,13 @@ public void saveNamespace() throws IOException {
     namesystem.saveNamespace();
   }
   
+  @Override // ClientProtocol
+  public long rollEdits() throws AccessControlException, IOException {
+    namesystem.checkOperation(OperationCategory.JOURNAL);
+    CheckpointSignature sig = namesystem.rollEditLog();
+    return sig.getCurSegmentTxId();
+  }
+
   @Override // ClientProtocol
   public void refreshNodes() throws IOException {
     namesystem.refreshNodes();

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/tools/DFSAdmin.java

@@ -420,6 +420,14 @@ public int saveNamespace() throws IOException {
     return exitCode;
   }
 
+  public int rollEdits() throws IOException {
+    DistributedFileSystem dfs = getDFS();
+    long txid = dfs.rollEdits();
+    System.out.println("Successfully rolled edit logs.");
+    System.out.println("New segment starts at txid " + txid);
+    return 0;
+  }
+  
   /**
    * Command to enable/disable/check restoring of failed storage replicas in the namenode.
    * Usage: java DFSAdmin -restoreFailedStorage true|false|check
@@ -516,6 +524,7 @@ private void printHelp(String cmd) {
       "The full syntax is: \n\n" +
       "hadoop dfsadmin [-report] [-safemode <enter | leave | get | wait>]\n" +
       "\t[-saveNamespace]\n" +
+      "\t[-rollEdits]\n" +
       "\t[-restoreFailedStorage true|false|check]\n" +
       "\t[-refreshNodes]\n" +
       "\t[" + SetQuotaCommand.USAGE + "]\n" +
@@ -548,6 +557,10 @@ private void printHelp(String cmd) {
     "Save current namespace into storage directories and reset edits log.\n" +
     "\t\tRequires superuser permissions and safe mode.\n";
 
+    String rollEdits = "-rollEdits:\t" +
+    "Rolls the edit log.\n" +
+    "\t\tRequires superuser permissions.\n";
+    
     String restoreFailedStorage = "-restoreFailedStorage:\t" +
     "Set/Unset/Check flag to attempt restore of failed storage replicas if they become available.\n" +
     "\t\tRequires superuser permissions.\n";
@@ -625,6 +638,8 @@ private void printHelp(String cmd) {
       System.out.println(safemode);
     } else if ("saveNamespace".equals(cmd)) {
       System.out.println(saveNamespace);
+    } else if ("rollEdits".equals(cmd)) {
+      System.out.println(rollEdits);
     } else if ("restoreFailedStorage".equals(cmd)) {
       System.out.println(restoreFailedStorage);
     } else if ("refreshNodes".equals(cmd)) {
@@ -664,6 +679,7 @@ private void printHelp(String cmd) {
       System.out.println(report);
       System.out.println(safemode);
       System.out.println(saveNamespace);
+      System.out.println(rollEdits);
       System.out.println(restoreFailedStorage);
       System.out.println(refreshNodes);
       System.out.println(finalizeUpgrade);
@@ -859,6 +875,9 @@ private static void printUsage(String cmd) {
     } else if ("-saveNamespace".equals(cmd)) {
       System.err.println("Usage: java DFSAdmin"
                          + " [-saveNamespace]");
+    } else if ("-rollEdits".equals(cmd)) {
+      System.err.println("Usage: java DFSAdmin"
+                         + " [-rollEdits]");
     } else if ("-restoreFailedStorage".equals(cmd)) {
       System.err.println("Usage: java DFSAdmin"
           + " [-restoreFailedStorage true|false|check ]");
@@ -913,6 +932,7 @@ private static void printUsage(String cmd) {
       System.err.println("           [-report]");
       System.err.println("           [-safemode enter | leave | get | wait]");
       System.err.println("           [-saveNamespace]");
+      System.err.println("           [-rollEdits]");
       System.err.println("           [-restoreFailedStorage true|false|check]");
       System.err.println("           [-refreshNodes]");
       System.err.println("           [-finalizeUpgrade]");
@@ -970,6 +990,11 @@ public int run(String[] argv) throws Exception {
         printUsage(cmd);
         return exitCode;
       }
+    } else if ("-rollEdits".equals(cmd)) {
+      if (argv.length != 1) {
+        printUsage(cmd);
+        return exitCode;
+      }      
     } else if ("-restoreFailedStorage".equals(cmd)) {
       if (argv.length != 2) {
         printUsage(cmd);
@@ -1048,6 +1073,8 @@ public int run(String[] argv) throws Exception {
         setSafeMode(argv, i);
       } else if ("-saveNamespace".equals(cmd)) {
         exitCode = saveNamespace();
+      } else if ("-rollEdits".equals(cmd)) {
+        exitCode = rollEdits();
       } else if ("-restoreFailedStorage".equals(cmd)) {
         exitCode = restoreFaileStorage(argv[i]);
       } else if ("-refreshNodes".equals(cmd)) {

hadoop-hdfs-project/hadoop-hdfs/src/main/proto/ClientNamenodeProtocol.proto

@@ -276,6 +276,13 @@ message SaveNamespaceRequestProto { // no parameters
 message SaveNamespaceResponseProto { // void response
 }
 
+message RollEditsRequestProto { // no parameters
+}
+
+message RollEditsResponseProto { // response
+  required uint64 newSegmentTxId = 1;
+}
+
 message RestoreFailedStorageRequestProto {
   required string arg = 1;
 }
@@ -472,6 +479,8 @@ service ClientNamenodeProtocol {
       returns(SetSafeModeResponseProto);
   rpc saveNamespace(SaveNamespaceRequestProto)
       returns(SaveNamespaceResponseProto);
+  rpc rollEdits(RollEditsRequestProto)
+      returns(RollEditsResponseProto);
   rpc restoreFailedStorage(RestoreFailedStorageRequestProto)
       returns(RestoreFailedStorageResponseProto);
   rpc refreshNodes(RefreshNodesRequestProto) returns(RefreshNodesResponseProto);

hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testHDFSConf.xml

@@ -15885,6 +15885,23 @@
       </comparators>
     </test>
 
+    <!-- Test for rollEdits -->
+    <test> <!-- TESTED -->
+      <description>rollEdits: test rollEdits admin command</description>
+      <test-commands>
+        <dfs-admin-command>-fs NAMENODE -rollEdits</dfs-admin-command>
+      </test-commands>
+      <cleanup-commands>
+        <!-- no cleanup -->
+      </cleanup-commands>
+      <comparators>
+        <comparator>
+          <type>RegexpComparator</type>
+          <expected-output>New segment starts at txid \d+</expected-output>
+        </comparator>
+      </comparators>
+    </test>
+
     <!-- Test for refreshNodes -->
     <test> <!-- TESTED -->
       <description>refreshNodes: to refresh the nodes</description>