From b8c74a8a25e950622964a5909e2169d174dc8f68 Mon Sep 17 00:00:00 2001
From: Hitesh Shah <hitesh@apache.org>
Date: Fri, 22 Mar 2013 19:11:01 +0000
Subject: [PATCH] MAPREDUCE-5083. MiniMRCluster should use a random component
 when creating an actual cluster. Contributed by Siddharth Seth.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1459932 13f79535-47bb-0310-9956-ffa450edef68
---
 hadoop-mapreduce-project/CHANGES.txt                |  3 +++
 .../hadoop/mapred/MiniMRClientClusterFactory.java   | 13 +++++++++----
 .../org/apache/hadoop/mapred/MiniMRCluster.java     |  5 ++++-
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/hadoop-mapreduce-project/CHANGES.txt b/hadoop-mapreduce-project/CHANGES.txt
index 5bee7337582..771ea575828 100644
--- a/hadoop-mapreduce-project/CHANGES.txt
+++ b/hadoop-mapreduce-project/CHANGES.txt
@@ -250,6 +250,9 @@ Release 2.0.5-beta - UNRELEASED
     MAPREDUCE-3872. Fix an event handling races in ContainerLauncherImpl.
     (Robert Kanter via sseth)
 
+    MAPREDUCE-5083. MiniMRCluster should use a random component when creating an
+    actual cluster (Siddharth Seth via hitesh)
+
 Release 2.0.4-alpha - UNRELEASED
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRClientClusterFactory.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRClientClusterFactory.java
index 99130ca331c..023da480822 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRClientClusterFactory.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRClientClusterFactory.java
@@ -38,6 +38,11 @@ public class MiniMRClientClusterFactory {
 
   public static MiniMRClientCluster create(Class<?> caller, int noOfNMs,
       Configuration conf) throws IOException {
+    return create(caller, caller.getSimpleName(), noOfNMs, conf);
+  }
+
+  public static MiniMRClientCluster create(Class<?> caller, String identifier,
+      int noOfNMs, Configuration conf) throws IOException {
 
     if (conf == null) {
       conf = new Configuration();
@@ -45,7 +50,7 @@ public class MiniMRClientClusterFactory {
 
     FileSystem fs = FileSystem.get(conf);
 
-    Path testRootDir = new Path("target", caller.getSimpleName() + "-tmpDir")
+    Path testRootDir = new Path("target", identifier + "-tmpDir")
         .makeQualified(fs);
     Path appJar = new Path(testRootDir, "MRAppJar.jar");
 
@@ -65,10 +70,10 @@ public class MiniMRClientClusterFactory {
     fs.setPermission(remoteCallerJar, new FsPermission("744"));
     job.addFileToClassPath(remoteCallerJar);
 
-    MiniMRYarnCluster miniMRYarnCluster = new MiniMRYarnCluster(caller
-        .getSimpleName(), noOfNMs);
+    MiniMRYarnCluster miniMRYarnCluster = new MiniMRYarnCluster(identifier,
+        noOfNMs);
     job.getConfiguration().set("minimrclientcluster.caller.name",
-        caller.getSimpleName());
+        identifier);
     job.getConfiguration().setInt("minimrclientcluster.nodemanagers.number",
         noOfNMs);
     miniMRYarnCluster.init(job.getConfiguration());
diff --git a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRCluster.java b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRCluster.java
index 627bae3c1ee..5320621c740 100644
--- a/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRCluster.java
+++ b/hadoop-mapreduce-project/hadoop-mapreduce-client/hadoop-mapreduce-client-jobclient/src/test/java/org/apache/hadoop/mapred/MiniMRCluster.java
@@ -18,6 +18,7 @@
 package org.apache.hadoop.mapred;
 
 import java.io.IOException;
+import java.util.Random;
 
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
@@ -177,8 +178,10 @@ public class MiniMRCluster {
       int numTrackerToExclude, Clock clock) throws IOException {
     if (conf == null) conf = new JobConf();
     FileSystem.setDefaultUri(conf, namenode);
+    String identifier = this.getClass().getSimpleName() + "_"
+        + Integer.toString(new Random().nextInt(Integer.MAX_VALUE));
     mrClientCluster = MiniMRClientClusterFactory.create(this.getClass(),
-        numTaskTrackers, conf);
+        identifier, numTaskTrackers, conf);
   }
 
   public UserGroupInformation getUgi() {