HDFS-3869. Expose non-file journal manager details in web UI. Contributed by Todd Lipcon.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/HDFS-3077@1380978 13f79535-47bb-0310-9956-ffa450edef68

hadoop-hdfs-project/hadoop-hdfs/CHANGES.HDFS-3077.txt

@@ -38,3 +38,5 @@ HDFS-3845. Fixes for edge cases in QJM recovery protocol (todd)
 HDFS-3877. QJM: Provide defaults for dfs.journalnode.*address (eli)
 
 HDFS-3863. Track last "committed" txid in QJM (todd)
+
+HDFS-3869. Expose non-file journal manager details in web UI (todd)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/AsyncLogger.java

@@ -140,4 +140,10 @@ interface AsyncLogger {
    * after this point, and any in-flight RPCs may throw an exception.
    */
   public void close();
+
+  /**
+   * Append an HTML-formatted report for this logger's status to the provided
+   * StringBuilder. This is displayed on the NN web UI.
+   */
+  public void appendHtmlReport(StringBuilder sb);
 }

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/AsyncLoggerSet.java

@@ -33,6 +33,7 @@ import org.apache.hadoop.hdfs.qjournal.protocol.QJournalProtocolProtos.SegmentSt
 import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo;
 import org.apache.hadoop.hdfs.server.protocol.RemoteEditLogManifest;
 import org.apache.hadoop.ipc.RemoteException;
+import org.apache.jasper.compiler.JspUtil;
 
 import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Preconditions;
@@ -190,6 +191,24 @@ class AsyncLoggerSet {
   int size() {
     return loggers.size();
   }
+  
+  /**
+   * Append an HTML-formatted status readout on the current
+   * state of the underlying loggers.
+   * @param sb the StringBuilder to append to
+   */
+  void appendHtmlReport(StringBuilder sb) {
+    sb.append("<table class=\"storage\">");
+    sb.append("<thead><tr><td>JN</td><td>Status</td></tr></thead>\n");
+    for (AsyncLogger l : loggers) {
+      sb.append("<tr>");
+      sb.append("<td>" + JspUtil.escapeXml(l.toString()) + "</td>");
+      sb.append("<td>");
+      l.appendHtmlReport(sb);
+      sb.append("</td></tr>\n");
+    }
+    sb.append("</table>");
+  }
 
   /**
    * @return the (mutable) list of loggers, for use in tests to

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/IPCLoggerChannel.java

@@ -84,7 +84,12 @@ public class IPCLoggerChannel implements AsyncLogger {
    * The number of bytes of edits data still in the queue.
    */
   private int queuedEditsSizeBytes = 0;
-
+  
+  /**
+   * The highest txid that has been successfully logged on the remote JN.
+   */
+  private long highestAckedTxId = 0;
+  
   /**
    * The maximum number of bytes that can be pending in the queue.
    * This keeps the writer from hitting OOME if one of the loggers
@@ -262,6 +267,9 @@ public class IPCLoggerChannel implements AsyncLogger {
         public Void call() throws IOException {
           getProxy().journal(createReqInfo(),
               segmentTxId, firstTxnId, numTxns, data);
+          synchronized (IPCLoggerChannel.this) {
+            highestAckedTxId = firstTxnId + numTxns - 1;
+          }
           return null;
         }
       });
@@ -398,4 +406,14 @@ public class IPCLoggerChannel implements AsyncLogger {
   public String toString() {
     return "Channel to journal node " + addr; 
   }
-}
+
+  @Override
+  public synchronized void appendHtmlReport(StringBuilder sb) {
+    sb.append("Written txid ").append(highestAckedTxId);
+    long behind = committedTxId - highestAckedTxId;
+    assert behind >= 0;
+    if (behind > 0) {
+      sb.append(" (" + behind + " behind)");
+    }
+  }
+}

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/qjournal/client/QuorumOutputStream.java

@@ -109,4 +109,13 @@ class QuorumOutputStream extends EditLogOutputStream {
       loggers.setCommittedTxId(firstTxToFlush + numReadyTxns - 1);
     }
   }
+
+  @Override
+  public String generateHtmlReport() {
+    StringBuilder sb = new StringBuilder();
+    sb.append("Writing segment beginning at txid " + segmentTxId + "<br/>\n");
+    loggers.appendHtmlReport(sb);
+    return sb.toString();
+  }
+  
 }

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

@@ -24,6 +24,7 @@ import static org.apache.hadoop.util.Time.now;
 
 import org.apache.hadoop.classification.InterfaceAudience;
 import org.apache.hadoop.classification.InterfaceStability;
+import org.apache.jasper.compiler.JspUtil;
 
 /**
  * A generic abstract class to support journaling of edits logs into 
@@ -132,4 +133,12 @@ public abstract class EditLogOutputStream implements Closeable {
   protected long getNumSync() {
     return numSync;
   }
+
+  /**
+   * @return a short HTML snippet suitable for describing the current
+   * status of the stream
+   */
+  public String generateHtmlReport() {
+    return JspUtil.escapeXml(this.toString());
+  }
 }

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

@@ -26,6 +26,7 @@ import java.util.LinkedList;
 import java.util.List;
 import java.util.PriorityQueue;
 import java.util.SortedSet;
+import java.util.concurrent.CopyOnWriteArrayList;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -147,7 +148,7 @@ public class JournalSet implements JournalManager {
       return journal;
     }
 
-    private boolean isDisabled() {
+    boolean isDisabled() {
       return disabled;
     }
 
@@ -165,8 +166,12 @@ public class JournalSet implements JournalManager {
       return required;
     }
   }
-  
-  private List<JournalAndStream> journals = Lists.newArrayList();
+ 
+  // COW implementation is necessary since some users (eg the web ui) call
+  // getAllJournalStreams() and then iterate. Since this is rarely
+  // mutated, there is no performance concern.
+  private List<JournalAndStream> journals =
+      new CopyOnWriteArrayList<JournalSet.JournalAndStream>();
   final int minimumRedundantJournals;
   
   JournalSet(int minimumRedundantResources) {
@@ -519,7 +524,6 @@ public class JournalSet implements JournalManager {
     }
   }
   
-  @VisibleForTesting
   List<JournalAndStream> getAllJournalStreams() {
     return journals;
   }

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

@@ -48,6 +48,7 @@ import org.apache.hadoop.hdfs.server.blockmanagement.DatanodeManager;
 import org.apache.hadoop.hdfs.server.common.JspHelper;
 import org.apache.hadoop.hdfs.server.common.Storage;
 import org.apache.hadoop.hdfs.server.common.Storage.StorageDirectory;
+import org.apache.hadoop.hdfs.server.namenode.JournalSet.JournalAndStream;
 import org.apache.hadoop.hdfs.server.protocol.NamenodeProtocols;
 import org.apache.hadoop.http.HttpConfig;
 import org.apache.hadoop.io.Text;
@@ -61,6 +62,8 @@ import org.apache.hadoop.util.Time;
 import org.apache.hadoop.util.VersionInfo;
 import org.znerd.xmlenc.XMLOutputter;
 
+import com.google.common.base.Preconditions;
+
 class NamenodeJspHelper {
   static String getSafeModeText(FSNamesystem fsn) {
     if (!fsn.isInSafeMode())
@@ -213,6 +216,52 @@ class NamenodeJspHelper {
 
       out.print("</table></div>\n");
     }
+    
+    /**
+     * Generate an HTML report containing the current status of the HDFS
+     * journals.
+     */
+    void generateJournalReport(JspWriter out, NameNode nn,
+        HttpServletRequest request) throws IOException {
+      FSEditLog log = nn.getFSImage().getEditLog();
+      Preconditions.checkArgument(log != null, "no edit log set in %s", nn);
+      
+      out.println("<h3> " + nn.getRole() + " Journal Status: </h3>");
+
+      out.println("<b>Current transaction ID:</b> " +
+          nn.getFSImage().getLastAppliedOrWrittenTxId() + "<br/>");
+      
+      
+      boolean openForWrite = log.isOpenForWrite();
+      
+      out.println("<div class=\"dfstable\">");
+      out.println("<table class=\"storage\" title=\"NameNode Journals\">\n"
+              + "<thead><tr><td><b>Journal Manager</b></td><td><b>State</b></td></tr></thead>");
+      for (JournalAndStream jas : log.getJournals()) {
+        out.print("<tr>");
+        out.print("<td>" + jas.getManager());
+        if (jas.isRequired()) {
+          out.print(" [required]");
+        }
+        out.print("</td><td>");
+        
+        if (jas.isDisabled()) {
+          out.print("<span class=\"failed\">Failed</span>");
+        } else if (openForWrite) {
+          EditLogOutputStream elos = jas.getCurrentStream();
+          if (elos != null) {
+            out.println(elos.generateHtmlReport());
+          } else {
+            out.println("not currently writing");
+          }
+        } else {
+          out.println("open for read");
+        }
+        out.println("</td></tr>");
+      }
+      
+      out.println("</table></div>");
+    }
 
     void generateHealthReport(JspWriter out, NameNode nn,
         HttpServletRequest request) throws IOException {

hadoop-hdfs-project/hadoop-hdfs/src/main/webapps/hdfs/dfshealth.jsp

@@ -60,8 +60,10 @@
 <%= NamenodeJspHelper.getCorruptFilesWarning(fsn)%>
 
 <% healthjsp.generateHealthReport(out, nn, request); %>
-<hr>
+<% healthjsp.generateJournalReport(out, nn, request); %>
+<hr/>
 <% healthjsp.generateConfReport(out, nn, request); %>
+<hr>
 <%
 out.println(ServletUtil.htmlFooter());
 %>

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

@@ -17,17 +17,18 @@
  */
 package org.apache.hadoop.hdfs.qjournal;
 
-import static org.junit.Assert.assertTrue;
-import static org.junit.Assert.fail;
+import static org.junit.Assert.*;
 
 import java.io.File;
 import java.io.IOException;
+import java.net.URL;
 
 import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.FileSystem;
 import org.apache.hadoop.fs.FileUtil;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.DFSConfigKeys;
+import org.apache.hadoop.hdfs.DFSTestUtil;
 import org.apache.hadoop.hdfs.HdfsConfiguration;
 import org.apache.hadoop.hdfs.MiniDFSCluster;
 import org.apache.hadoop.hdfs.server.namenode.NameNode;
@@ -185,4 +186,41 @@ public class TestNNWithQJM {
           "Unable to start log segment 1: too few journals", ioe);
     }
   }
+  
+  @Test
+  public void testWebPageHasQjmInfo() throws Exception {
+    conf.set(DFSConfigKeys.DFS_NAMENODE_NAME_DIR_KEY,
+        MiniDFSCluster.getBaseDirectory() + "/TestNNWithQJM/image");
+    conf.set(DFSConfigKeys.DFS_NAMENODE_EDITS_DIR_KEY,
+        mjc.getQuorumJournalURI("myjournal").toString());
+    
+    MiniDFSCluster cluster = new MiniDFSCluster.Builder(conf)
+      .numDataNodes(0)
+      .manageNameDfsDirs(false)
+      .build();
+    try {
+      URL url = new URL("http://localhost:"
+          + NameNode.getHttpAddress(cluster.getConfiguration(0)).getPort()
+          + "/dfshealth.jsp");
+      
+      cluster.getFileSystem().mkdirs(TEST_PATH);
+      
+      String contents = DFSTestUtil.urlGet(url); 
+      assertTrue(contents.contains("Channel to journal node"));
+      assertTrue(contents.contains("Written txid 2"));
+
+      // Stop one JN, do another txn, and make sure it shows as behind
+      // stuck behind the others.
+      mjc.getJournalNode(0).stopAndJoin(0);
+      
+      cluster.getFileSystem().delete(TEST_PATH, true);
+      
+      contents = DFSTestUtil.urlGet(url); 
+      System.out.println(contents);
+      assertTrue(contents.contains("(1 behind)"));
+    } finally {
+      cluster.shutdown();
+    }
+
+  }
 }