From b36f712736dfb89067e237dcf3837de8853a3c0a Mon Sep 17 00:00:00 2001
From: Michael Stack <stack@apache.org>
Date: Fri, 14 Dec 2007 17:12:09 +0000
Subject: [PATCH] HADOOP-2286 Add being able to shutdown regionservers

git-svn-id: https://svn.apache.org/repos/asf/lucene/hadoop/trunk/src/contrib/hbase@604233 13f79535-47bb-0310-9956-ffa450edef68
---
 CHANGES.txt                                   |  2 ++
 bin/hbase-daemon.sh                           | 12 ++++---
 .../apache/hadoop/hbase/HRegionServer.java    | 34 +++++++++++++++++--
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/CHANGES.txt b/CHANGES.txt
index 2eda2387bc6..8fd4664be87 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -123,8 +123,10 @@ Trunk (unreleased changes)
                (Edward Yoon via Stack)
    HADOOP-2351 If select command returns no result, it doesn't need to show the
                header information (Edward Yoon via Stack)
+   HADOOP-2285 Add being able to shutdown regionservers (Dennis Kubes via Stack)
                
 
+
 Release 0.15.1
 Branch 0.15
 
diff --git a/bin/hbase-daemon.sh b/bin/hbase-daemon.sh
index ac5725b1849..0a21b4d3df4 100755
--- a/bin/hbase-daemon.sh
+++ b/bin/hbase-daemon.sh
@@ -128,10 +128,14 @@ case $startStop in
     if [ -f $pid ]; then
       if kill -0 `cat $pid` > /dev/null 2>&1; then
         echo -n stopping $command
-        nohup nice -n $HADOOP_NICENESS "$HBASE_HOME"/bin/hbase \
-            --hadoop "${HADOOP_HOME}" \
-            --config "${HADOOP_CONF_DIR}" --hbaseconfig "${HBASE_CONF_DIR}" \
-            $command $startStop "$@" > "$log" 2>&1 < /dev/null &
+        if [ "$command" = "regionserver" ]; then
+          kill `cat $pid` > /dev/null 2>&1
+        else
+          nohup nice -n $HADOOP_NICENESS "$HBASE_HOME"/bin/hbase \
+              --hadoop "${HADOOP_HOME}" \
+              --config "${HADOOP_CONF_DIR}" --hbaseconfig "${HBASE_CONF_DIR}" \
+              $command $startStop "$@" > "$log" 2>&1 < /dev/null &
+        fi
         while kill -0 `cat $pid` > /dev/null 2>&1; do
           echo -n "."
           sleep 1;
diff --git a/src/java/org/apache/hadoop/hbase/HRegionServer.java b/src/java/org/apache/hadoop/hbase/HRegionServer.java
index b93ea7c464e..49bf9e088c1 100644
--- a/src/java/org/apache/hadoop/hbase/HRegionServer.java
+++ b/src/java/org/apache/hadoop/hbase/HRegionServer.java
@@ -132,6 +132,31 @@ public class HRegionServer implements HConstants, HRegionInterface, Runnable {
   
   /** region server process name */
   public static final String REGIONSERVER = "regionserver";
+  
+  /**
+   * Thread to shutdown the region server in an orderly manner.  This thread
+   * is registered as a shutdown hook in the HRegionServer constructor and is
+   * only called when the HRegionServer receives a kill signal.
+   */
+  class ShutdownThread 
+    extends Thread {
+    
+    private final HRegionServer instance;
+    
+    public ShutdownThread(HRegionServer instance) {
+      this.instance = instance;
+    }
+
+    public synchronized void start() {
+      LOG.info("Starting shutdown thread.");
+      
+      // tell the region server to stop and wait for it to complete
+      instance.stop();
+      instance.join();
+      LOG.info("Shutdown thread complete");
+    }    
+    
+  }
 
   /** Queue entry passed to flusher, compactor and splitter threads */
   class QueueEntry implements Delayed {
@@ -646,6 +671,10 @@ public class HRegionServer implements HConstants, HRegionInterface, Runnable {
      this.leases = new Leases(
        conf.getInt("hbase.regionserver.lease.period", 3 * 60 * 1000),
        this.threadWakeFrequency);
+     
+     // Register shutdown hook for HRegionServer, runs an orderly shutdown
+     // when a kill signal is recieved
+     Runtime.getRuntime().addShutdownHook(new ShutdownThread(this));
   }
 
   /**
@@ -1736,8 +1765,9 @@ public class HRegionServer implements HConstants, HRegionInterface, Runnable {
       }
       
       if (cmd.equals("stop")) {
-        printUsageAndExit("There is no regionserver stop mechanism. To stop " +
-          "regionservers, shutdown the hbase master");
+        printUsageAndExit("To shutdown the regionserver run " +
+        		"bin/hbase-daemon.sh stop regionserver or send a kill signal to" +
+        		"the regionserver pid");
       }
       
       // Print out usage if we get to here.