HBASE-2998 rolling-restart.sh shouldn't rely on zoo.cfg

git-svn-id: https://svn.apache.org/repos/asf/hbase/trunk@1026470 13f79535-47bb-0310-9956-ffa450edef68

CHANGES.txt

@@ -603,6 +603,7 @@ Release 0.21.0 - Unreleased
                work w/ new region naming convention from HBASE-2531
    HBASE-3140  Rest schema modification throw null pointer exception
                (David Worms via Stack)
+   HBASE-2998  rolling-restart.sh shouldn't rely on zoo.cfg
 
 
   IMPROVEMENTS

bin/hbase

@@ -262,7 +262,9 @@ elif [ "$COMMAND" = "zookeeper" ] ; then
     HBASE_OPTS="$HBASE_OPTS $HBASE_ZOOKEEPER_OPTS"
   fi
 elif [ "$COMMAND" = "zkcli" ] ; then
-  CLASS='org.apache.zookeeper.ZooKeeperMain'
+  # ZooKeeperMainServerArg returns '-server HOST:PORT' or empty string.
+  SERVER_ARG=`"$bin"/hbase org.apache.hadoop.hbase.zookeeper.ZooKeeperMainServerArg` 
+  CLASS="org.apache.zookeeper.ZooKeeperMain ${SERVER_ARG}"
 elif [ "$COMMAND" = "classpath" ] ; then
   echo $CLASSPATH
   exit 0

bin/hbase-daemon.sh

@@ -74,7 +74,7 @@ hbase_rotate_log ()
 wait_until_done ()
 {
     p=$1
-    cnt=${HBASE_SLAVE_TIMEOUT:-60}
+    cnt=${HBASE_SLAVE_TIMEOUT:-300}
     origcnt=$cnt
     while kill -0 $p > /dev/null 2>&1; do
       if [ $cnt -gt 1 ]; then

src/main/java/org/apache/hadoop/hbase/catalog/CatalogTracker.java

@@ -264,7 +264,7 @@ public class CatalogTracker {
         if (!refresh) {
           return current;
         }
-        if (verifyRegionLocation(current, META_REGION)) {
+        if (verifyRegionLocation(current, this.metaLocation, META_REGION)) {
           return current;
         }
         resetMetaLocation();
@@ -278,7 +278,7 @@ public class CatalogTracker {
         return null;
       }
       HRegionInterface newConnection = getCachedConnection(newLocation);
-      if (verifyRegionLocation(newConnection, META_REGION)) {
+      if (verifyRegionLocation(newConnection, this.metaLocation, META_REGION)) {
         setMetaLocation(newLocation);
         return newConnection;
       }
@@ -402,6 +402,7 @@ public class CatalogTracker {
   }
 
   private boolean verifyRegionLocation(HRegionInterface metaServer,
+      final HServerAddress address,
       byte [] regionName)
   throws IOException {
     if (metaServer == null) {
@@ -428,7 +429,8 @@ public class CatalogTracker {
         throw e;
       }
     }
-    LOG.info("Failed verification of " + Bytes.toString(regionName) + "; " + t);
+    LOG.info("Failed verification of " + Bytes.toString(regionName) +
+      " at address=" + address + "; " + t);
     return false;
   }
 
@@ -452,7 +454,8 @@ public class CatalogTracker {
       throw e;
     }
     return (connection == null)? false:
-      verifyRegionLocation(connection, HRegionInfo.ROOT_REGIONINFO.getRegionName());
+      verifyRegionLocation(connection,this.rootRegionTracker.getRootRegionLocation(),
+        HRegionInfo.ROOT_REGIONINFO.getRegionName());
   }
 
   /**
@@ -485,9 +488,7 @@ public class CatalogTracker {
       LOG.info("-ROOT- is not assigned; continuing");
     } else if (hsi.getServerAddress().equals(rootHsa)) {
       result.setFirst(true);
-      LOG.info(hsi.getServerName() + " carrying -ROOT-; deleting " +
+      LOG.info(hsi.getServerName() + " carrying -ROOT-; unsetting");
-        "-ROOT- location from meta");
-      RootLocationEditor.deleteRootLocation(this.zookeeper);
     }
     HServerAddress metaHsa = getMetaLocation();
     if (metaHsa == null) {

src/main/java/org/apache/hadoop/hbase/executor/ExecutorService.java

@@ -170,7 +170,9 @@ public class ExecutorService {
       throw new RuntimeException("An executor service with the name " + name +
       " is already running (2)!");
     }
-    LOG.debug("Starting executor service: " + name);
+    LOG.debug("Starting executor service name=" + name +
+      ", corePoolSize=" + hbes.threadPoolExecutor.getCorePoolSize() +
+      ", maxPoolSize=" + hbes.threadPoolExecutor.getMaximumPoolSize());
   }
 
   boolean isExecutorServiceRunning(String name) {

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

@@ -37,6 +37,7 @@ import java.util.TreeMap;
 import java.util.concurrent.ConcurrentNavigableMap;
 import java.util.concurrent.ConcurrentSkipListMap;
 import java.util.concurrent.Executors;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -45,7 +46,6 @@ import org.apache.hadoop.hbase.Chore;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.HServerInfo;
 import org.apache.hadoop.hbase.HTableDescriptor;
-import org.apache.hadoop.hbase.NotServingRegionException;
 import org.apache.hadoop.hbase.Server;
 import org.apache.hadoop.hbase.Stoppable;
 import org.apache.hadoop.hbase.catalog.CatalogTracker;
@@ -67,11 +67,13 @@ import org.apache.hadoop.hbase.zookeeper.ZKAssign;
 import org.apache.hadoop.hbase.zookeeper.ZKTableDisable;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil;
 import org.apache.hadoop.hbase.zookeeper.ZooKeeperListener;
+import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
 import org.apache.hadoop.hbase.zookeeper.ZKUtil.NodeAndData;
 import org.apache.hadoop.io.Writable;
-import org.apache.hadoop.ipc.RemoteException;
+import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.KeeperException.NoNodeException;
+import org.apache.zookeeper.data.Stat;
 
 import com.google.common.util.concurrent.ThreadFactoryBuilder;
 
@@ -659,19 +661,27 @@ public class AssignmentManager extends ZooKeeperListener {
     }
     // Presumption is that only this thread will be updating the state at this
     // time; i.e. handlers on backend won't be trying to set it to OPEN, etc.
+    AtomicInteger counter = new AtomicInteger(0);
+    CreateUnassignedAsyncCallback cb =
+      new CreateUnassignedAsyncCallback(this.watcher, destination, counter);
     for (RegionState state: states) {
-      if (!setOfflineInZooKeeper(state)) {
+      if (!asyncSetOfflineInZooKeeper(state, cb, state)) {
         return;
       }
     }
-    for (RegionState state: states) {
+    // Wait until all unassigned nodes have been put up and watchers set.
-      // Transition RegionState to PENDING_OPEN here in master; means we've
+    int total = regions.size();
-      // sent the open.  We're a little ahead of ourselves here since we've not
+    for (int oldCounter = 0; true;) {
-      // yet sent out the actual open but putting this state change after the
+      int count = counter.get();
-      // call to open risks our writing PENDING_OPEN after state has been moved
+      if (oldCounter != count) {
-      // to OPENING by the regionserver.
+        LOG.info(destination.getServerName() + " unassigned znodes=" + count +
-      state.update(RegionState.State.PENDING_OPEN);
+          " of total=" + total);
+        oldCounter = count;
       }
+      if (count == total) break;
+      Threads.sleep(1);
+    }
+    // Move on to open regions.
     try {
       // Send OPEN RPC. This can fail if the server on other end is is not up.
       this.serverManager.sendRegionOpen(destination, regions);
@@ -682,6 +692,72 @@ public class AssignmentManager extends ZooKeeperListener {
     LOG.debug("Bulk assigning done for " + destination.getServerName());
   }
 
+  /**
+   * Callback handler for create unassigned znodes used during bulk assign.
+   */
+  static class CreateUnassignedAsyncCallback implements AsyncCallback.StringCallback {
+    private final Log LOG = LogFactory.getLog(CreateUnassignedAsyncCallback.class);
+    private final ZooKeeperWatcher zkw;
+    private final HServerInfo destination;
+    private final AtomicInteger counter;
+
+    CreateUnassignedAsyncCallback(final ZooKeeperWatcher zkw,
+        final HServerInfo destination, final AtomicInteger counter) {
+      this.zkw = zkw;
+      this.destination = destination;
+      this.counter = counter;
+    }
+
+    @Override
+    public void processResult(int rc, String path, Object ctx, String name) {
+      if (rc != 0) {
+        // Thisis resultcode.  If non-zero, need to resubmit.
+        LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
+          "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
+        this.zkw.abort("Connectionloss writing unassigned at " + path +
+          ", rc=" + rc, null);
+        return;
+      }
+      LOG.debug("rs=" + (RegionState)ctx + ", server=" + this.destination.getServerName());
+      // Async exists to set a watcher so we'll get triggered when
+      // unassigned node changes.
+      this.zkw.getZooKeeper().exists(path, this.zkw,
+        new ExistsUnassignedAsyncCallback(this.counter), ctx);
+    }
+  }
+
+  /**
+   * Callback handler for the exists call that sets watcher on unassigned znodes.
+   * Used during bulk assign on startup.
+   */
+  static class ExistsUnassignedAsyncCallback implements AsyncCallback.StatCallback {
+    private final Log LOG = LogFactory.getLog(ExistsUnassignedAsyncCallback.class);
+    private final AtomicInteger counter;
+
+    ExistsUnassignedAsyncCallback(final AtomicInteger counter) {
+      this.counter = counter;
+    }
+
+    @Override
+    public void processResult(int rc, String path, Object ctx, Stat stat) {
+      if (rc != 0) {
+        // Thisis resultcode.  If non-zero, need to resubmit.
+        LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
+          "FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
+        return;
+      }
+      RegionState state = (RegionState)ctx;
+      LOG.debug("rs=" + state);
+      // Transition RegionState to PENDING_OPEN here in master; means we've
+      // sent the open.  We're a little ahead of ourselves here since we've not
+      // yet sent out the actual open but putting this state change after the
+      // call to open risks our writing PENDING_OPEN after state has been moved
+      // to OPENING by the regionserver.
+      state.update(RegionState.State.PENDING_OPEN);
+      this.counter.addAndGet(1);
+    }
+  }
+
   /**
    * @param region
    * @return
@@ -717,6 +793,10 @@ public class AssignmentManager extends ZooKeeperListener {
    */
   private void assign(final RegionState state) {
     if (!setOfflineInZooKeeper(state)) return;
+    if (this.master.isStopped()) {
+      LOG.debug("Server stopped; skipping assign of " + state);
+      return;
+    }
     RegionPlan plan = getRegionPlan(state);
     if (plan == null) return; // Should get reassigned later when RIT times out.
     try {
@@ -768,6 +848,31 @@ public class AssignmentManager extends ZooKeeperListener {
     return true;
   }
 
+  /**
+   * Set region as OFFLINED up in zookeeper asynchronously.
+   * @param state
+   * @return True if we succeeded, false otherwise (State was incorrect or failed
+   * updating zk).
+   */
+  boolean asyncSetOfflineInZooKeeper(final RegionState state,
+      final AsyncCallback.StringCallback cb, final Object ctx) {
+    if (!state.isClosed() && !state.isOffline()) {
+        new RuntimeException("Unexpected state trying to OFFLINE; " + state);
+      this.master.abort("Unexpected state trying to OFFLINE; " + state,
+        new IllegalStateException());
+      return false;
+    }
+    state.update(RegionState.State.OFFLINE);
+    try {
+      ZKAssign.asyncCreateNodeOffline(master.getZooKeeper(), state.getRegion(),
+        master.getServerName(), cb, ctx);
+    } catch (KeeperException e) {
+      master.abort("Unexpected ZK exception creating/setting node OFFLINE", e);
+      return false;
+    }
+    return true;
+  }
+
   /**
    * @param state
    * @return Plan for passed <code>state</code> (If none currently, it creates one or

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

@@ -259,41 +259,31 @@ implements HMasterInterface, HMasterRegionInterface, MasterServices, Server {
       this.activeMasterManager = new ActiveMasterManager(zooKeeper, address, this);
       this.zooKeeper.registerListener(activeMasterManager);
       stallIfBackupMaster(this.conf, this.activeMasterManager);
-      activeMasterManager.blockUntilBecomingActiveMaster();
+      this.activeMasterManager.blockUntilBecomingActiveMaster();
-
       // We are either the active master or we were asked to shutdown
-
       if (!this.stopped) {
-        // We are active master.  Finish init and loop until we are closed.
         finishInitialization();
         loop();
-        // Once we break out of here, we are being shutdown
+      }
-
+    } catch (Throwable t) {
-        // Stop chores
+      abort("Unhandled exception. Starting shutdown.", t);
+    } finally {
       stopChores();
-
       // Wait for all the remaining region servers to report in IFF we were
       // running a cluster shutdown AND we were NOT aborting.
       if (!this.abort && this.serverManager.isClusterShutdown()) {
         this.serverManager.letRegionServersShutdown();
       }
       stopServiceThreads();
-      }
-
-      // Handle either a backup or active master being stopped
-
       // Stop services started for both backup and active masters
-      this.activeMasterManager.stop();
+      if (this.activeMasterManager != null) this.activeMasterManager.stop();
       this.catalogTracker.stop();
       this.serverManager.stop();
       this.assignmentManager.stop();
       HConnectionManager.deleteConnection(this.conf, true);
       this.zooKeeper.close();
-      LOG.info("HMaster main thread exiting");
-
-    } catch (Throwable t) {
-      abort("Unhandled exception. Starting shutdown.", t);
     }
+    LOG.info("HMaster main thread exiting");
   }
 
   private void loop() {
@@ -543,7 +533,7 @@ implements HMasterInterface, HMasterRegionInterface, MasterServices, Server {
     if (LOG.isDebugEnabled()) {
       LOG.debug("Stopping service threads");
     }
-    this.rpcServer.stop();
+    if (this.rpcServer != null) this.rpcServer.stop();
     // Clean up and close up shop
     if (this.infoServer != null) {
       LOG.info("Stopping infoServer");
@@ -553,7 +543,7 @@ implements HMasterInterface, HMasterRegionInterface, MasterServices, Server {
         ex.printStackTrace();
       }
     }
-    this.executorService.shutdown();
+    if (this.executorService != null) this.executorService.shutdown();
   }
 
   private static Thread getAndStartBalancerChore(final HMaster master) {

src/main/java/org/apache/hadoop/hbase/master/handler/OpenedRegionHandler.java

@@ -19,8 +19,6 @@
  */
 package org.apache.hadoop.hbase.master.handler;
 
-import java.io.IOException;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HRegionInfo;

src/main/java/org/apache/hadoop/hbase/regionserver/handler/OpenRegionHandler.java

@@ -67,6 +67,10 @@ public class OpenRegionHandler extends EventHandler {
   public void process() throws IOException {
     final String name = regionInfo.getRegionNameAsString();
     LOG.debug("Processing open of " + name);
+    if (this.server.isStopped()) {
+      LOG.info("Server stopping, skipping open of " + name);
+      return;
+    }
     final String encodedName = regionInfo.getEncodedName();
 
     // TODO: Previously we would check for root region availability (but only that it

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

@@ -26,6 +26,7 @@ import org.apache.commons.logging.LogFactory;
 import org.apache.hadoop.hbase.HRegionInfo;
 import org.apache.hadoop.hbase.executor.RegionTransitionData;
 import org.apache.hadoop.hbase.executor.EventHandler.EventType;
+import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.KeeperException.Code;
 import org.apache.zookeeper.KeeperException.NoNodeException;
@@ -148,6 +149,36 @@ public class ZKAssign {
     }
   }
 
+  /**
+   * Creates an unassigned node in the OFFLINE state for the specified region.
+   * <p>
+   * Runs asynchronously.  Depends on no pre-existing znode.
+   *
+   * <p>Sets a watcher on the unassigned region node.
+   *
+   * @param zkw zk reference
+   * @param region region to be created as offline
+   * @param serverName server event originates from
+   * @param cb
+   * @param ctx
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NodeExistsException if node already exists
+   */
+  public static void asyncCreateNodeOffline(ZooKeeperWatcher zkw,
+      HRegionInfo region, String serverName,
+      final AsyncCallback.StringCallback cb, final Object ctx)
+  throws KeeperException {
+    LOG.debug(zkw.prefix("Async create of unassigned node for " +
+      region.getEncodedName() + " with OFFLINE state"));
+    RegionTransitionData data = new RegionTransitionData(
+        EventType.M_ZK_REGION_OFFLINE, region.getRegionName(), serverName);
+    synchronized(zkw.getNodes()) {
+      String node = getNodeName(zkw, region.getEncodedName());
+      zkw.getNodes().add(node);
+      ZKUtil.asyncCreate(zkw, node, data.getBytes(), cb, ctx);
+    }
+  }
+
   /**
    * Forces an existing unassigned node to the OFFLINE state for the specified
    * region.

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

@@ -33,7 +33,7 @@ import org.apache.hadoop.hbase.HBaseConfiguration;
 public class ZKServerTool {
   /**
    * Run the tool.
-   * @param args Command line arguments. First arg is path to zookeepers file.
+   * @param args Command line arguments.
    */
   public static void main(String args[]) {
     Configuration conf = HBaseConfiguration.create();

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

@@ -37,6 +37,7 @@ import org.apache.hadoop.hbase.HServerAddress;
 import org.apache.hadoop.hbase.HServerInfo;
 import org.apache.hadoop.hbase.executor.RegionTransitionData;
 import org.apache.hadoop.hbase.util.Bytes;
+import org.apache.zookeeper.AsyncCallback;
 import org.apache.zookeeper.CreateMode;
 import org.apache.zookeeper.KeeperException;
 import org.apache.zookeeper.Watcher;
@@ -809,6 +810,30 @@ public class ZKUtil {
     }
   }
 
+  /**
+   * Async creates the specified node with the specified data.
+   *
+   * <p>Throws an exception if the node already exists.
+   *
+   * <p>The node created is persistent and open access.
+   *
+   * @param zkw zk reference
+   * @param znode path of node to create
+   * @param data data of node to create
+   * @param cb
+   * @param ctx
+   * @return version of node created
+   * @throws KeeperException if unexpected zookeeper exception
+   * @throws KeeperException.NodeExistsException if node already exists
+   */
+  public static void asyncCreate(ZooKeeperWatcher zkw,
+      String znode, byte [] data, final AsyncCallback.StringCallback cb,
+      final Object ctx)
+  throws KeeperException, KeeperException.NodeExistsException {
+    zkw.getZooKeeper().create(znode, data, Ids.OPEN_ACL_UNSAFE,
+       CreateMode.PERSISTENT, cb, ctx);
+  }
+
   /**
    * Creates the specified node, if the node does not exist.  Does not set a
    * watch and fails silently if the node already exists.

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

@@ -0,0 +1,68 @@
+/**
+ * Copyright 2010 The Apache Software Foundation
+ *
+ * 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.hbase.zookeeper;
+
+import java.util.Properties;
+import java.util.Map.Entry;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+
+/**
+ * Tool for reading a ZooKeeper server from HBase XML configuration producing
+ * the '-server host:port' argument to pass ZooKeeperMain.  This program
+ * emits either '-server HOST:PORT" where HOST is one of the zk ensemble
+ * members plus zk client port OR it emits '' if no zk servers found (Yes,
+ * it emits '-server' too).
+ */
+public class ZooKeeperMainServerArg {
+  public String parse(final Configuration c) {
+    // Note that we do not simply grab the property
+    // HConstants.ZOOKEEPER_QUORUM from the HBaseConfiguration because the
+    // user may be using a zoo.cfg file.
+    Properties zkProps = ZKConfig.makeZKProps(c);
+    String host = null;
+    String clientPort = null;
+    for (Entry<Object, Object> entry: zkProps.entrySet()) {
+      String key = entry.getKey().toString().trim();
+      String value = entry.getValue().toString().trim();
+      if (key.startsWith("server.") && host == null) {
+        String[] parts = value.split(":");
+        host = parts[0];
+      } else if (key.endsWith("clientPort")) {
+        clientPort = value;
+      }
+      if (host != null && clientPort != null) break;
+    }
+    return host != null && clientPort != null? host + ":" + clientPort: null;
+  }
+
+  /**
+   * Run the tool.
+   * @param args Command line arguments. First arg is path to zookeepers file.
+   */
+  public static void main(String args[]) {
+    Configuration conf = HBaseConfiguration.create();
+    String hostport = new ZooKeeperMainServerArg().parse(conf);
+    System.out.println((hostport == null || hostport.length() == 0)? "":
+      "-server " + hostport);
+  }
+}

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

@@ -47,7 +47,7 @@ import org.apache.zookeeper.ZooKeeper;
  * <p>This class also holds and manages the connection to ZooKeeper.  Code to
  * deal with connection related events and exceptions are handled here.
  */
-public class ZooKeeperWatcher implements Watcher {
+public class ZooKeeperWatcher implements Watcher, Abortable {
   private static final Log LOG = LogFactory.getLog(ZooKeeperWatcher.class);
 
   // Identifiier for this watcher (for logging only).  Its made of the prefix
@@ -372,4 +372,9 @@ public class ZooKeeperWatcher implements Watcher {
     } catch (InterruptedException e) {
     }
   }
+
+  @Override
+  public void abort(String why, Throwable e) {
+    this.abortable.abort(why, e);
+  }
 }

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

@@ -0,0 +1,44 @@
+/**
+ * Copyright 2010 The Apache Software Foundation
+ *
+ * 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.hbase.zookeeper;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.hbase.HBaseConfiguration;
+import org.junit.Test;
+
+
+public class TestZooKeeperMainServerArg {
+  private final ZooKeeperMainServerArg parser = new ZooKeeperMainServerArg();
+
+  @Test public void test() {
+    Configuration c = HBaseConfiguration.create();
+    assertEquals("localhost:" + c.get("hbase.zookeeper.property.clientPort"),
+      parser.parse(c));
+    final String port = "1234";
+    c.set("hbase.zookeeper.property.clientPort", port);
+    c.set("hbase.zookeeper.quorum", "example.com");
+    assertEquals("example.com:" + port, parser.parse(c));
+    c.set("hbase.zookeeper.quorum", "example1.com,example2.com,example3.com");
+    assertTrue(port, parser.parse(c).matches("example[1-3]\\.com:" + port));
+  }
+}