HBASE-4138 If zookeeper.znode.parent is not specifed explicitly in Client

code then HTable object loops continuously waiting for the root region
               by using /hbase as the base node.(ramkrishna.s.vasudevan)


git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1152220 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -178,6 +178,9 @@ Release 0.91.0 - Unreleased
    HBASE-4083  If Enable table is not completed and is partial, then scanning of
                the table is not working (ramkrishna.s.vasudevan)
    HBASE-4144  RS does not abort if the initialization of RS fails (ramkrishna.s.vasudevan)
+   HBASE-4138  If zookeeper.znode.parent is not specifed explicitly in Client
+               code then HTable object loops continuously waiting for the root region
+               by using /hbase as the base node.(ramkrishna.s.vasudevan)
 
   IMPROVEMENTS
    HBASE-3290  Max Compaction Size (Nicolas Spiegelberg via Stack)  

src/main/java/org/apache/hadoop/hbase/client/HConnectionManager.java

@@ -570,7 +570,7 @@ public class HConnectionManager {
           return master;
         }
       }
-
+      checkIfBaseNodeAvailable();
       ServerName sn = null;
       synchronized (this.masterLock) {
         for (int tries = 0;
@@ -632,6 +632,15 @@ public class HConnectionManager {
       return this.master;
     }
 
+    private void checkIfBaseNodeAvailable() throws MasterNotRunningException {
+      if (false == masterAddressTracker.checkIfBaseNodeAvailable()) {
+        String errorMsg = "Check the value configured in 'zookeeper.znode.parent'. "
+            + "There could be a mismatch with the one configured in the master.";
+        LOG.error(errorMsg);
+        throw new MasterNotRunningException(errorMsg);
+      }
+    }
+    
     public boolean isMasterRunning()
     throws MasterNotRunningException, ZooKeeperConnectionException {
       if (this.master == null) {

src/main/java/org/apache/hadoop/hbase/master/HMaster.java

@@ -238,7 +238,7 @@ implements HMasterInterface, HMasterRegionInterface, MasterServices, Server {
     if (this.conf.get("mapred.task.id") == null) {
       this.conf.set("mapred.task.id", "hb_m_" + this.serverName.toString());
     }
-    this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":" + isa.getPort(), this);
+    this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":" + isa.getPort(), this, true);
     this.metrics = new MasterMetrics(getServerName().toString());
   }
 
@@ -1218,7 +1218,7 @@ implements HMasterInterface, HMasterRegionInterface, MasterServices, Server {
   private boolean tryRecoveringExpiredZKSession() throws InterruptedException,
       IOException, KeeperException {
     this.zooKeeper = new ZooKeeperWatcher(conf, MASTER + ":"
-        + this.serverName.getPort(), this);
+        + this.serverName.getPort(), this, true);
 
     MonitoredTask status = 
       TaskMonitor.get().createStatus("Recovering expired ZK session");

src/main/java/org/apache/hadoop/hbase/regionserver/HRegionServer.java

@@ -555,6 +555,12 @@ public class HRegionServer implements HRegionInterface, HBaseRPCErrorHandler,
    */
   private void blockAndCheckIfStopped(ZooKeeperNodeTracker tracker)
       throws IOException, InterruptedException {
+    if (false == tracker.checkIfBaseNodeAvailable()) {
+      String errorMsg = "Check the value configured in 'zookeeper.znode.parent'. "
+          + "There could be a mismatch with the one configured in the master.";
+      LOG.error(errorMsg);
+      abort(errorMsg);
+    }
     while (tracker.blockUntilAvailable(this.msgInterval) == null) {
       if (this.stopped) {
         throw new IOException("Received the shutdown message while waiting.");

src/main/java/org/apache/hadoop/hbase/zookeeper/RootRegionTracker.java

@@ -71,6 +71,12 @@ public class RootRegionTracker extends ZooKeeperNodeTracker {
    */
   public ServerName waitRootRegionLocation(long timeout)
   throws InterruptedException {
+    if (false == checkIfBaseNodeAvailable()) {
+      String errorMsg = "Check the value configured in 'zookeeper.znode.parent'. "
+          + "There could be a mismatch with the one configured in the master.";
+      LOG.error(errorMsg);
+      throw new IllegalArgumentException(errorMsg);
+    }
     return dataToServerName(super.blockUntilAvailable(timeout));
   }
 

src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperNodeTracker.java

@@ -19,6 +19,8 @@
  */
 package org.apache.hadoop.hbase.zookeeper;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.Abortable;
 import org.apache.zookeeper.KeeperException;
 
@@ -32,6 +34,8 @@ import org.apache.zookeeper.KeeperException;
  * RegionServers.
  */
 public abstract class ZooKeeperNodeTracker extends ZooKeeperListener {
+  
+  static final Log LOG = LogFactory.getLog(ZooKeeperNodeTracker.class);
   /** Path of node being tracked */
   protected final String node;
 
@@ -179,4 +183,24 @@ public abstract class ZooKeeperNodeTracker extends ZooKeeperListener {
       nodeCreated(path);
     }
   }
+  
+  /**
+   * Checks if the baseznode set as per the property 'zookeeper.znode.parent'
+   * exists.
+   * @return true if baseznode exists.
+   *         false if doesnot exists.
+   */
+  public boolean checkIfBaseNodeAvailable() {
+    try {
+      if (ZKUtil.checkExists(watcher, watcher.baseZNode) == -1) {
+        return false;
+      }
+    } catch (KeeperException e) {
+      abortable
+          .abort(
+              "Exception while checking if basenode exists.",
+              e);
+    }
+    return true;
+  }
 }

src/main/java/org/apache/hadoop/hbase/zookeeper/ZooKeeperWatcher.java

@@ -90,6 +90,7 @@ public class ZooKeeperWatcher implements Watcher, Abortable {
 
   private final Exception constructorCaller;
 
+  
   /**
    * Instantiate a ZooKeeper connection and watcher.
    * @param descriptor Descriptive string that is added to zookeeper sessionid
@@ -98,7 +99,18 @@ public class ZooKeeperWatcher implements Watcher, Abortable {
    * @throws ZooKeeperConnectionException 
    */
   public ZooKeeperWatcher(Configuration conf, String descriptor,
-      Abortable abortable)
+      Abortable abortable) throws ZooKeeperConnectionException, IOException {
+    this(conf, descriptor, abortable, false);
+  }
+  /**
+   * Instantiate a ZooKeeper connection and watcher.
+   * @param descriptor Descriptive string that is added to zookeeper sessionid
+   * and used as identifier for this instance.
+   * @throws IOException
+   * @throws ZooKeeperConnectionException
+   */
+  public ZooKeeperWatcher(Configuration conf, String descriptor,
+      Abortable abortable, boolean canCreateBaseZNode)
   throws IOException, ZooKeeperConnectionException {
     this.conf = conf;
     // Capture a stack trace now.  Will print it out later if problem so we can
@@ -115,9 +127,14 @@ public class ZooKeeperWatcher implements Watcher, Abortable {
     this.abortable = abortable;
     setNodeNames(conf);
     this.recoverableZooKeeper = ZKUtil.connect(conf, quorum, this, descriptor);
+    if (canCreateBaseZNode) {
+      createBaseZNodes();
+    }
+  }
+
+  private void createBaseZNodes() throws ZooKeeperConnectionException {
     try {
       // Create all the necessary "directories" of znodes
-      // TODO: Move this to an init method somewhere so not everyone calls it?
       ZKUtil.createAndFailSilent(this, baseZNode);
       ZKUtil.createAndFailSilent(this, assignmentZNode);
       ZKUtil.createAndFailSilent(this, rsZNode);

src/test/java/org/apache/hadoop/hbase/catalog/TestCatalogTracker.java

@@ -84,7 +84,7 @@ public class TestCatalogTracker {
       }
     };
     this.watcher = new ZooKeeperWatcher(UTIL.getConfiguration(),
-      this.getClass().getSimpleName(), this.abortable);
+      this.getClass().getSimpleName(), this.abortable, true);
   }
 
   @After public void after() {

src/test/java/org/apache/hadoop/hbase/master/TestRestartCluster.java

@@ -67,7 +67,7 @@ public class TestRestartCluster {
   @Test (timeout=300000) public void testRestartClusterAfterKill()
   throws Exception {
     UTIL.startMiniZKCluster();
-    zooKeeper = new ZooKeeperWatcher(UTIL.getConfiguration(), "cluster1", null);
+    zooKeeper = new ZooKeeperWatcher(UTIL.getConfiguration(), "cluster1", null, true);
 
     // create the unassigned region, throw up a region opened state for META
     String unassignedZNode = zooKeeper.assignmentZNode;

src/test/java/org/apache/hadoop/hbase/regionserver/handler/TestOpenRegionHandler.java

@@ -76,7 +76,7 @@ public class TestOpenRegionHandler {
     final ZooKeeperWatcher zk;
 
     MockServer() throws ZooKeeperConnectionException, IOException {
-      this.zk =  new ZooKeeperWatcher(HTU.getConfiguration(), NAME.toString(), this);
+      this.zk =  new ZooKeeperWatcher(HTU.getConfiguration(), NAME.toString(), this, true);
     }
 
     @Override

src/test/java/org/apache/hadoop/hbase/replication/TestReplication.java

@@ -104,7 +104,7 @@ public class TestReplication {
     utility1 = new HBaseTestingUtility(conf1);
     utility1.startMiniZKCluster();
     MiniZooKeeperCluster miniZK = utility1.getZkCluster();
-    zkw1 = new ZooKeeperWatcher(conf1, "cluster1", null);
+    zkw1 = new ZooKeeperWatcher(conf1, "cluster1", null, true);
     admin = new ReplicationAdmin(conf1);
     LOG.info("Setup first Zk");
 
@@ -116,7 +116,7 @@ public class TestReplication {
 
     utility2 = new HBaseTestingUtility(conf2);
     utility2.setZkCluster(miniZK);
-    zkw2 = new ZooKeeperWatcher(conf2, "cluster2", null);
+    zkw2 = new ZooKeeperWatcher(conf2, "cluster2", null, true);
 
     slaveClusterKey = conf2.get(HConstants.ZOOKEEPER_QUORUM)+":" +
             conf2.get("hbase.zookeeper.property.clientPort")+":/2";

src/test/java/org/apache/hadoop/hbase/zookeeper/TestZKTable.java

@@ -60,7 +60,7 @@ public class TestZKTable {
       }
     };
     ZooKeeperWatcher zkw = new ZooKeeperWatcher(TEST_UTIL.getConfiguration(),
-      name, abortable);
+      name, abortable, true);
     ZKTable zkt = new ZKTable(zkw);
     assertTrue(zkt.isEnabledTable(name));
     assertFalse(zkt.isDisablingTable(name));