HDFS-2397. Undeprecate SecondaryNameNode. Contributed by Eli Collins

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1235135 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/src/main/docs/src/documentation/content/xdocs/commands_manual.xml

@@ -753,11 +753,6 @@
 			
 			<section>
 				<title> secondarynamenode </title>
-				<note>
-					The Secondary NameNode has been deprecated. Instead, consider using the
-					<a href="http://hadoop.apache.org/hdfs/docs/current/hdfs_user_guide.html#Checkpoint+Node">Checkpoint Node</a> or 
-					<a href="http://hadoop.apache.org/hdfs/docs/current/hdfs_user_guide.html#Backup+Node">Backup Node</a>. 
-				</note>
 				<p>	
 					Runs the HDFS secondary 
 					namenode. See <a href="http://hadoop.apache.org/hdfs/docs/current/hdfs_user_guide.html#Secondary+NameNode">Secondary NameNode</a> 

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

@@ -276,6 +276,8 @@ Release 0.23.1 - UNRELEASED
 
     HDFS-2818. Fix a missing space issue in HDFS webapps' title tags. (Devaraj K via harsh)
 
+    HDFS-2397. Undeprecate SecondaryNameNode (eli)
+
   OPTIMIZATIONS
 
     HDFS-2130. Switch default checksum to CRC32C. (todd)

hadoop-hdfs-project/hadoop-hdfs/src/main/docs/src/documentation/content/xdocs/hdfs_user_guide.xml

@@ -112,17 +112,18 @@
     		problems.
     	</li>
     	<li>
-    		Secondary NameNode (deprecated): performs periodic checkpoints of the 
+    		Secondary NameNode: performs periodic checkpoints of the 
     		namespace and helps keep the size of file containing log of HDFS 
     		modifications within certain limits at the NameNode.
-    		Replaced by Checkpoint node.
     	</li>
+
     	<li>
     		Checkpoint node: performs periodic checkpoints of the namespace and
     		helps minimize the size of the log stored at the NameNode 
     		containing changes to the HDFS.
-    		Replaces the role previously filled by the Secondary NameNode. 
-    		NameNode allows multiple Checkpoint nodes simultaneously, 
+    		Replaces the role previously filled by the Secondary NameNode,
+                though is not yet battle hardened.
+    		The NameNode allows multiple Checkpoint nodes simultaneously, 
     		as long as there are no Backup nodes registered with the system.
     	</li>
     	<li>
@@ -132,6 +133,7 @@
     		which is always in sync with the active NameNode namespace state.
     		Only one Backup node may be registered with the NameNode at once.
     	</li>
+
       </ul>
     </li>
     </ul>
@@ -234,12 +236,6 @@
    
    </section> 
 	<section> <title>Secondary NameNode</title>
-   <note>
-   The Secondary NameNode has been deprecated. 
-   Instead, consider using the 
-   <a href="hdfs_user_guide.html#Checkpoint+node">Checkpoint Node</a> or 
-   <a href="hdfs_user_guide.html#Backup+node">Backup Node</a>.
-   </note>
    <p>	
      The NameNode stores modifications to the file system as a log
      appended to a native file system file, <code>edits</code>. 
@@ -287,7 +283,9 @@
      <a href="http://hadoop.apache.org/common/docs/current/commands_manual.html#secondarynamenode">secondarynamenode</a>.
    </p>
    
-   </section><section> <title> Checkpoint Node </title>
+   </section>
+
+   <section> <title> Checkpoint Node </title>
    <p>NameNode persists its namespace using two files: <code>fsimage</code>,
       which is the latest checkpoint of the namespace and <code>edits</code>,
       a journal (log) of changes to the namespace since the checkpoint.

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

@@ -87,7 +87,6 @@ import com.google.common.collect.ImmutableList;
  * primary NameNode.
  *
  **********************************************************/
-@Deprecated // use BackupNode with -checkpoint argument instead.
 @InterfaceAudience.Private
 public class SecondaryNameNode implements Runnable {
     

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

@@ -204,7 +204,6 @@ public class TestCheckpoint extends TestCase {
   /*
    * Simulate namenode crashing after rolling edit log.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryNamenodeError1()
     throws IOException {
     LOG.info("Starting testSecondaryNamenodeError1");
@@ -266,7 +265,6 @@ public class TestCheckpoint extends TestCase {
   /*
    * Simulate a namenode crash after uploading new image
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryNamenodeError2() throws IOException {
     LOG.info("Starting testSecondaryNamenodeError2");
     Configuration conf = new HdfsConfiguration();
@@ -325,7 +323,6 @@ public class TestCheckpoint extends TestCase {
   /*
    * Simulate a secondary namenode crash after rolling the edit log.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryNamenodeError3() throws IOException {
     LOG.info("Starting testSecondaryNamenodeError3");
     Configuration conf = new HdfsConfiguration();
@@ -395,7 +392,6 @@ public class TestCheckpoint extends TestCase {
    * back to the name-node.
    * Used to truncate primary fsimage file.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryFailsToReturnImage() throws IOException {
     LOG.info("Starting testSecondaryFailsToReturnImage");
     Configuration conf = new HdfsConfiguration();
@@ -472,7 +468,6 @@ public class TestCheckpoint extends TestCase {
    * @param errorType the ErrorSimulator type to trigger
    * @param exceptionSubstring an expected substring of the triggered exception
    */
-  @SuppressWarnings("deprecation")
   private void doSendFailTest(int errorType, String exceptionSubstring)
       throws IOException {
     Configuration conf = new HdfsConfiguration();
@@ -587,7 +582,6 @@ public class TestCheckpoint extends TestCase {
   /**
    * Test that the SecondaryNameNode properly locks its storage directories.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryNameNodeLocking() throws Exception {
     // Start a primary NN so that the secondary will start successfully
     Configuration conf = new HdfsConfiguration();
@@ -680,7 +674,6 @@ public class TestCheckpoint extends TestCase {
    * 2. if the NN does not contain an image, importing a checkpoint
    *    succeeds and re-saves the image
    */
-  @SuppressWarnings("deprecation")
   public void testImportCheckpoint() throws Exception {
     Configuration conf = new HdfsConfiguration();
     Path testPath = new Path("/testfile");
@@ -761,16 +754,12 @@ public class TestCheckpoint extends TestCase {
       throw new IOException("Cannot create directory " + dir);
   }
   
-  // This deprecation suppress warning does not work due to known Java bug:
-  // http://bugs.sun.com/view_bug.do?bug_id=6460147
-  @SuppressWarnings("deprecation")
   SecondaryNameNode startSecondaryNameNode(Configuration conf
                                           ) throws IOException {
     conf.set(DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY, "0.0.0.0:0");
     return new SecondaryNameNode(conf);
   }
   
-  @SuppressWarnings("deprecation")
   SecondaryNameNode startSecondaryNameNode(Configuration conf, int index)
       throws IOException {
     Configuration snnConf = new Configuration(conf);
@@ -783,7 +772,6 @@ public class TestCheckpoint extends TestCase {
   /**
    * Tests checkpoint in HDFS.
    */
-  @SuppressWarnings("deprecation")
   public void testCheckpoint() throws IOException {
     Path file1 = new Path("checkpoint.dat");
     Path file2 = new Path("checkpoint2.dat");
@@ -1010,7 +998,6 @@ public class TestCheckpoint extends TestCase {
    * - it then fails again for the same reason
    * - it then tries to checkpoint a third time
    */
-  @SuppressWarnings("deprecation")
   public void testCheckpointAfterTwoFailedUploads() throws IOException {
     MiniDFSCluster cluster = null;
     SecondaryNameNode secondary = null;
@@ -1065,7 +1052,6 @@ public class TestCheckpoint extends TestCase {
    * 
    * @throws IOException
    */
-  @SuppressWarnings("deprecation")
   public void testMultipleSecondaryNamenodes() throws IOException {
     Configuration conf = new HdfsConfiguration();
     String nameserviceId1 = "ns1";
@@ -1115,7 +1101,6 @@ public class TestCheckpoint extends TestCase {
    * Test that the secondary doesn't have to re-download image
    * if it hasn't changed.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryImageDownload() throws IOException {
     LOG.info("Starting testSecondaryImageDownload");
     Configuration conf = new HdfsConfiguration();
@@ -1198,7 +1183,6 @@ public class TestCheckpoint extends TestCase {
    * It verifies that this works even though the earlier-txid checkpoint gets
    * uploaded after the later-txid checkpoint.
    */
-  @SuppressWarnings("deprecation")
   public void testMultipleSecondaryNNsAgainstSameNN() throws Exception {
     Configuration conf = new HdfsConfiguration();
 
@@ -1284,7 +1268,6 @@ public class TestCheckpoint extends TestCase {
    * It verifies that one of the two gets an error that it's uploading a
    * duplicate checkpoint, and the other one succeeds.
    */
-  @SuppressWarnings("deprecation")
   public void testMultipleSecondaryNNsAgainstSameNN2() throws Exception {
     Configuration conf = new HdfsConfiguration();
 
@@ -1383,7 +1366,6 @@ public class TestCheckpoint extends TestCase {
    * is running. The secondary should shut itself down if if talks to a NN
    * with the wrong namespace.
    */
-  @SuppressWarnings("deprecation")
   public void testReformatNNBetweenCheckpoints() throws IOException {
     MiniDFSCluster cluster = null;
     SecondaryNameNode secondary = null;
@@ -1638,7 +1620,6 @@ public class TestCheckpoint extends TestCase {
   /**
    * Test that the 2NN triggers a checkpoint after the configurable interval
    */
-  @SuppressWarnings("deprecation")
   public void testCheckpointTriggerOnTxnCount() throws Exception {
     MiniDFSCluster cluster = null;
     SecondaryNameNode secondary = null;
@@ -1692,7 +1673,6 @@ public class TestCheckpoint extends TestCase {
    * logs that connect the 2NN's old checkpoint to the current txid
    * get archived. Then, the 2NN tries to checkpoint again.
    */
-  @SuppressWarnings("deprecation")
   public void testSecondaryHasVeryOutOfDateImage() throws IOException {
     MiniDFSCluster cluster = null;
     SecondaryNameNode secondary = null;
@@ -1730,7 +1710,6 @@ public class TestCheckpoint extends TestCase {
     }
   }
   
-  @SuppressWarnings("deprecation")
   public void testCommandLineParsing() throws ParseException {
     SecondaryNameNode.CommandLineOpts opts =
       new SecondaryNameNode.CommandLineOpts();
@@ -1765,7 +1744,6 @@ public class TestCheckpoint extends TestCase {
     } catch (ParseException e) {}
   }
 
-  @SuppressWarnings("deprecation")
   private void cleanup(SecondaryNameNode snn) {
     if (snn != null) {
       try {
@@ -1781,7 +1759,6 @@ public class TestCheckpoint extends TestCase {
    * Assert that if any two files have the same name across the 2NNs
    * and NN, they should have the same content too.
    */
-  @SuppressWarnings("deprecation")
   private void assertParallelFilesInvariant(MiniDFSCluster cluster,
       ImmutableList<SecondaryNameNode> secondaries) throws Exception {
     List<File> allCurrentDirs = Lists.newArrayList();
@@ -1793,7 +1770,6 @@ public class TestCheckpoint extends TestCase {
         ImmutableSet.of("VERSION"));    
   }
   
-  @SuppressWarnings("deprecation")
   private List<File> getCheckpointCurrentDirs(SecondaryNameNode secondary) {
     List<File> ret = Lists.newArrayList();
     for (URI u : secondary.getCheckpointDirs()) {
@@ -1803,7 +1779,6 @@ public class TestCheckpoint extends TestCase {
     return ret;
   }
 
-  @SuppressWarnings("deprecation")
   private CheckpointStorage spyOnSecondaryImage(SecondaryNameNode secondary1) {
     CheckpointStorage spy = Mockito.spy((CheckpointStorage)secondary1.getFSImage());;
     secondary1.setFSImage(spy);
@@ -1813,7 +1788,6 @@ public class TestCheckpoint extends TestCase {
   /**
    * A utility class to perform a checkpoint in a different thread.
    */
-  @SuppressWarnings("deprecation")
   private static class DoCheckpointThread extends Thread {
     private final SecondaryNameNode snn;
     private volatile Throwable thrown = null;

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

@@ -120,9 +120,6 @@ public class TestNameEditsConfigs {
     assertTrue(!fileSys.exists(name));
   }
 
-  // This deprecation suppress warning does not work due to known Java bug:
-  // http://bugs.sun.com/view_bug.do?bug_id=6460147
-  @SuppressWarnings("deprecation")
   SecondaryNameNode startSecondaryNameNode(Configuration conf
                                           ) throws IOException {
     conf.set(DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY, "0.0.0.0:0");
@@ -142,7 +139,6 @@ public class TestNameEditsConfigs {
    * sure we are reading proper edits and image.
    * @throws Exception 
    */
-  @SuppressWarnings("deprecation")
   @Test
   public void testNameEditsConfigs() throws Exception {
     Path file1 = new Path("TestNameEditsConfigs1");

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

@@ -30,7 +30,6 @@ import org.junit.Test;
 
 public class TestSecondaryWebUi {
 
-  @SuppressWarnings("deprecation")
   @Test
   public void testSecondaryWebUi() throws IOException {
     Configuration conf = new Configuration();

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

@@ -121,7 +121,6 @@ public class TestStartup extends TestCase {
    * start MiniDFScluster, create a file (to create edits) and do a checkpoint  
    * @throws IOException
    */
-  @SuppressWarnings("deprecation")
   public void createCheckPoint() throws IOException {
     LOG.info("--starting mini cluster");
     // manage dirs parameter set to false 
@@ -303,7 +302,6 @@ public class TestStartup extends TestCase {
    * secondary node copies fsimage and edits into correct separate directories.
    * @throws IOException
    */
-  @SuppressWarnings("deprecation")
   public void testSNNStartup() throws IOException{
     //setUpConfig();
     LOG.info("--starting SecondNN startup test");

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

@@ -155,7 +155,6 @@ public class TestStorageRestore {
    * 7. run doCheckpoint
    * 8. verify that all the image and edits files are the same.
    */
-  @SuppressWarnings("deprecation")
   @Test
   public void testStorageRestore() throws Exception {
     int numDatanodes = 0;
@@ -312,7 +311,6 @@ public class TestStorageRestore {
    * then try to perform a checkpoint. The NN should not serve up the image or
    * edits from the restored (empty) dir.
    */
-  @SuppressWarnings("deprecation")
   @Test
   public void testMultipleSecondaryCheckpoint() throws IOException {
     

hadoop-mapreduce-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/ClusterSetup.apt.vm

@@ -95,7 +95,7 @@ Hadoop MapReduce Next Generation - Cluster Setup
 *--------------------------------------+--------------------------------------+
 | DataNode                             | HADOOP_DATANODE_OPTS                 |
 *--------------------------------------+--------------------------------------+
-| Backup NameNode                      | HADOOP_SECONDARYNAMENODE_OPTS        |
+| Secondary NameNode                   | HADOOP_SECONDARYNAMENODE_OPTS        |
 *--------------------------------------+--------------------------------------+
 | ResourceManager                      | YARN_RESOURCEMANAGER_OPTS            |
 *--------------------------------------+--------------------------------------+
@@ -537,15 +537,15 @@ Hadoop MapReduce Next Generation - Cluster Setup
       
   It's recommended to have them share a Unix group, for e.g. <<<hadoop>>>.
       
-*--------------------------------------+--------------------------------------+
-|| User:Group                          || Daemons                             |
-*--------------------------------------+--------------------------------------+
-| hdfs:hadoop                          | NameNode, Backup NameNode, DataNode  |
-*--------------------------------------+--------------------------------------+
-| yarn:hadoop                          | ResourceManager, NodeManager         |
-*--------------------------------------+--------------------------------------+
-| mapred:hadoop                        | MapReduce JobHistory Server          |  
-*--------------------------------------+--------------------------------------+
+*--------------------------------------+----------------------------------------------------------------------+
+|| User:Group                          || Daemons                                                             |
+*--------------------------------------+----------------------------------------------------------------------+
+| hdfs:hadoop                          | NameNode, Secondary NameNode, Checkpoint Node, Backup Node, DataNode |
+*--------------------------------------+----------------------------------------------------------------------+
+| yarn:hadoop                          | ResourceManager, NodeManager                                         |
+*--------------------------------------+----------------------------------------------------------------------+
+| mapred:hadoop                        | MapReduce JobHistory Server                                          |
+*--------------------------------------+----------------------------------------------------------------------+
       
   * <<<Permissions for both HDFS and local fileSystem paths>>>