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From ravip...@apache.org
Subject hadoop git commit: YARN-1964. Create Docker analog of the LinuxContainerExecutor in YARN
Date Wed, 12 Nov 2014 05:28:34 GMT
Repository: hadoop
Updated Branches:
  refs/heads/trunk 46f6f9d60 -> 53f64ee51


YARN-1964. Create Docker analog of the LinuxContainerExecutor in YARN


Project: http://git-wip-us.apache.org/repos/asf/hadoop/repo
Commit: http://git-wip-us.apache.org/repos/asf/hadoop/commit/53f64ee5
Tree: http://git-wip-us.apache.org/repos/asf/hadoop/tree/53f64ee5
Diff: http://git-wip-us.apache.org/repos/asf/hadoop/diff/53f64ee5

Branch: refs/heads/trunk
Commit: 53f64ee516d03f6ec87b41d77c214aa2fe4fa0ed
Parents: 46f6f9d
Author: Ravi Prakash <raviprak@apache.org>
Authored: Tue Nov 11 21:28:11 2014 -0800
Committer: Ravi Prakash <raviprak@apache.org>
Committed: Tue Nov 11 21:28:11 2014 -0800

----------------------------------------------------------------------
 hadoop-project/src/site/site.xml                |   1 +
 hadoop-yarn-project/CHANGES.txt                 |   3 +
 .../hadoop/yarn/conf/YarnConfiguration.java     |  14 +-
 .../src/main/resources/yarn-default.xml         |  12 +-
 .../server/nodemanager/ContainerExecutor.java   |  31 +
 .../nodemanager/DockerContainerExecutor.java    | 794 +++++++++++++++++++
 .../launcher/ContainerLaunch.java               |  36 +-
 .../TestDockerContainerExecutor.java            | 213 +++++
 .../TestDockerContainerExecutorWithMocks.java   | 259 ++++++
 .../launcher/TestContainerLaunch.java           |  10 +-
 .../src/site/apt/DockerContainerExecutor.apt.vm | 200 +++++
 11 files changed, 1533 insertions(+), 40 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-project/src/site/site.xml
----------------------------------------------------------------------
diff --git a/hadoop-project/src/site/site.xml b/hadoop-project/src/site/site.xml
index 6a61a83..4a2c2f8 100644
--- a/hadoop-project/src/site/site.xml
+++ b/hadoop-project/src/site/site.xml
@@ -124,6 +124,7 @@
       <item name="YARN Commands" href="hadoop-yarn/hadoop-yarn-site/YarnCommands.html"/>
       <item name="Scheduler Load Simulator" href="hadoop-sls/SchedulerLoadSimulator.html"/>
       <item name="NodeManager Restart" href="hadoop-yarn/hadoop-yarn-site/NodeManagerRestart.html"/>
+      <item name="DockerContainerExecutor" href="hadoop-yarn/hadoop-yarn-site/DockerContainerExecutor.html"/>
     </menu>
 
     <menu name="YARN REST APIs" inherit="top">

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/CHANGES.txt
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/CHANGES.txt b/hadoop-yarn-project/CHANGES.txt
index b40d9b7..c3bdf3d 100644
--- a/hadoop-yarn-project/CHANGES.txt
+++ b/hadoop-yarn-project/CHANGES.txt
@@ -89,6 +89,9 @@ Release 2.6.0 - 2014-11-15
 
   NEW FEATURES
 
+    YARN-1964. Create Docker analog of the LinuxContainerExecutor in YARN. (Abin 
+    Shahab via raviprak)
+
     YARN-2131. Add a way to format the RMStateStore. (Robert Kanter via kasha)
 
     YARN-1367. Changed NM to not kill containers on NM resync if RM work-preserving

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
index b459ee3..9b57a42 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/java/org/apache/hadoop/yarn/conf/YarnConfiguration.java
@@ -891,7 +891,19 @@ public class YarnConfiguration extends Configuration {
   /** The arguments to pass to the health check script.*/
   public static final String NM_HEALTH_CHECK_SCRIPT_OPTS = 
     NM_PREFIX + "health-checker.script.opts";
-  
+
+  /** The Docker image name(For DockerContainerExecutor).*/
+  public static final String NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME =
+    NM_PREFIX + "docker-container-executor.image-name";
+
+  /** The name of the docker executor (For DockerContainerExecutor).*/
+  public static final String NM_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME =
+    NM_PREFIX + "docker-container-executor.exec-name";
+
+  /** The default docker executor (For DockerContainerExecutor).*/
+  public static final String NM_DEFAULT_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME =
+          "/usr/bin/docker";
+
   /** The path to the Linux container executor.*/
   public static final String NM_LINUX_CONTAINER_EXECUTOR_PATH =
     NM_PREFIX + "linux-container-executor.path";

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
index 1e7d544..af4a5eb 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-common/src/main/resources/yarn-default.xml
@@ -23,7 +23,7 @@
 <!-- there.  If yarn-site.xml does not already exist, create it.      -->
 
 <configuration>
-  
+
   <!-- IPC Configs -->
   <property>
     <description>Factory to create client IPC classes.</description>
@@ -1146,6 +1146,16 @@
     <value>${hadoop.tmp.dir}/yarn-nm-recovery</value>
   </property>
 
+  <!--Docker configuration-->
+
+  <property>
+    <name>yarn.nodemanager.docker-container-executor.exec-name</name>
+    <value>/usr/bin/docker</value>
+    <description>
+      Name or path to the Docker client.
+    </description>
+  </property>
+
   <!--Map Reduce configuration-->
   <property>
     <name>yarn.nodemanager.aux-services.mapreduce_shuffle.class</name>

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/ContainerExecutor.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/ContainerExecutor.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/ContainerExecutor.java
index 4ce1a75..8133413 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/ContainerExecutor.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/ContainerExecutor.java
@@ -20,10 +20,13 @@ package org.apache.hadoop.yarn.server.nodemanager;
 
 import java.io.File;
 import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
 import java.net.InetSocketAddress;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ConcurrentMap;
 import java.util.concurrent.locks.ReentrantReadWriteLock;
@@ -211,6 +214,34 @@ public abstract class ContainerExecutor implements Configurable {
     }
   }
 
+  public void writeLaunchEnv(OutputStream out, Map<String, String> environment, Map<Path, List<String>> resources, List<String> command) throws IOException{
+    ContainerLaunch.ShellScriptBuilder sb = ContainerLaunch.ShellScriptBuilder.create();
+    if (environment != null) {
+      for (Map.Entry<String,String> env : environment.entrySet()) {
+        sb.env(env.getKey().toString(), env.getValue().toString());
+      }
+    }
+    if (resources != null) {
+      for (Map.Entry<Path,List<String>> entry : resources.entrySet()) {
+        for (String linkName : entry.getValue()) {
+          sb.symlink(entry.getKey(), new Path(linkName));
+        }
+      }
+    }
+
+    sb.command(command);
+
+    PrintStream pout = null;
+    try {
+      pout = new PrintStream(out);
+      sb.write(pout);
+    } finally {
+      if (out != null) {
+        out.close();
+      }
+    }
+  }
+
   public enum ExitCode {
     FORCE_KILLED(137),
     TERMINATED(143),

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/DockerContainerExecutor.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/DockerContainerExecutor.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/DockerContainerExecutor.java
new file mode 100644
index 0000000..d8dd890
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/DockerContainerExecutor.java
@@ -0,0 +1,794 @@
+/**
+ * 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.yarn.server.nodemanager;
+
+import com.google.common.annotations.VisibleForTesting;
+import com.google.common.base.Joiner;
+import com.google.common.base.Preconditions;
+import com.google.common.base.Strings;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.fs.CommonConfigurationKeys;
+import org.apache.hadoop.fs.FileContext;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.UnsupportedFileSystemException;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.io.IOUtils;
+import org.apache.hadoop.util.Shell;
+import org.apache.hadoop.util.Shell.ShellCommandExecutor;
+import org.apache.hadoop.util.StringUtils;
+import org.apache.hadoop.yarn.api.ApplicationConstants;
+import org.apache.hadoop.yarn.api.records.ContainerId;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.factory.providers.RecordFactoryProvider;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.Container;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.ContainerDiagnosticsUpdateEvent;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.launcher.ContainerLaunch;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.localizer.ContainerLocalizer;
+import org.apache.hadoop.yarn.util.ConverterUtils;
+
+import java.io.ByteArrayOutputStream;
+import java.io.DataOutputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.PrintStream;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Random;
+import java.util.Set;
+import java.util.regex.Pattern;
+import java.net.InetSocketAddress;
+
+import static org.apache.hadoop.fs.CreateFlag.CREATE;
+import static org.apache.hadoop.fs.CreateFlag.OVERWRITE;
+
+/**
+ * This executor will launch a docker container and run the task inside the container.
+ */
+public class DockerContainerExecutor extends ContainerExecutor {
+
+  private static final Log LOG = LogFactory
+      .getLog(DockerContainerExecutor.class);
+  public static final String DOCKER_CONTAINER_EXECUTOR_SCRIPT = "docker_container_executor";
+  public static final String DOCKER_CONTAINER_EXECUTOR_SESSION_SCRIPT = "docker_container_executor_session";
+
+  // This validates that the image is a proper docker image and would not crash docker.
+  public static final String DOCKER_IMAGE_PATTERN = "^(([\\w\\.-]+)(:\\d+)*\\/)?[\\w\\.:-]+$";
+
+
+  private final FileContext lfs;
+  private final Pattern dockerImagePattern;
+
+  public DockerContainerExecutor() {
+    try {
+      this.lfs = FileContext.getLocalFSFileContext();
+      this.dockerImagePattern = Pattern.compile(DOCKER_IMAGE_PATTERN);
+    } catch (UnsupportedFileSystemException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  protected void copyFile(Path src, Path dst, String owner) throws IOException {
+    lfs.util().copy(src, dst);
+  }
+
+  @Override
+  public void init() throws IOException {
+    String auth = getConf().get(CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION);
+    if (auth != null && !auth.equals("simple")) {
+      throw new IllegalStateException("DockerContainerExecutor only works with simple authentication mode");
+    }
+    String dockerExecutor = getConf().get(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME,
+      YarnConfiguration.NM_DEFAULT_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME);
+    if (!new File(dockerExecutor).exists()) {
+      throw new IllegalStateException("Invalid docker exec path: " + dockerExecutor);
+    }
+  }
+
+  @Override
+  public synchronized void startLocalizer(Path nmPrivateContainerTokensPath,
+                                          InetSocketAddress nmAddr, String user, String appId, String locId,
+                                          LocalDirsHandlerService dirsHandler)
+    throws IOException, InterruptedException {
+
+    List<String> localDirs = dirsHandler.getLocalDirs();
+    List<String> logDirs = dirsHandler.getLogDirs();
+
+    ContainerLocalizer localizer =
+      new ContainerLocalizer(lfs, user, appId, locId, getPaths(localDirs),
+        RecordFactoryProvider.getRecordFactory(getConf()));
+
+    createUserLocalDirs(localDirs, user);
+    createUserCacheDirs(localDirs, user);
+    createAppDirs(localDirs, user, appId);
+    createAppLogDirs(appId, logDirs, user);
+
+    // randomly choose the local directory
+    Path appStorageDir = getWorkingDir(localDirs, user, appId);
+
+    String tokenFn = String.format(ContainerLocalizer.TOKEN_FILE_NAME_FMT, locId);
+    Path tokenDst = new Path(appStorageDir, tokenFn);
+    copyFile(nmPrivateContainerTokensPath, tokenDst, user);
+    LOG.info("Copying from " + nmPrivateContainerTokensPath + " to " + tokenDst);
+    lfs.setWorkingDirectory(appStorageDir);
+    LOG.info("CWD set to " + appStorageDir + " = " + lfs.getWorkingDirectory());
+    // TODO: DO it over RPC for maintaining similarity?
+    localizer.runLocalization(nmAddr);
+  }
+
+
+  @Override
+  public int launchContainer(Container container,
+                             Path nmPrivateContainerScriptPath, Path nmPrivateTokensPath,
+                             String userName, String appId, Path containerWorkDir,
+                             List<String> localDirs, List<String> logDirs) throws IOException {
+    String containerImageName = container.getLaunchContext().getEnvironment()
+        .get(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME);
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("containerImageName from launchContext: " + containerImageName);
+    }
+    Preconditions.checkArgument(!Strings.isNullOrEmpty(containerImageName), "Container image must not be null");
+    containerImageName = containerImageName.replaceAll("['\"]", "");
+
+    Preconditions.checkArgument(saneDockerImage(containerImageName), "Image: " + containerImageName + " is not a proper docker image");
+    String dockerExecutor = getConf().get(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME,
+        YarnConfiguration.NM_DEFAULT_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME);
+
+    FsPermission dirPerm = new FsPermission(APPDIR_PERM);
+    ContainerId containerId = container.getContainerId();
+
+    // create container dirs on all disks
+    String containerIdStr = ConverterUtils.toString(containerId);
+    String appIdStr =
+        ConverterUtils.toString(
+            containerId.getApplicationAttemptId().
+                getApplicationId());
+    for (String sLocalDir : localDirs) {
+      Path usersdir = new Path(sLocalDir, ContainerLocalizer.USERCACHE);
+      Path userdir = new Path(usersdir, userName);
+      Path appCacheDir = new Path(userdir, ContainerLocalizer.APPCACHE);
+      Path appDir = new Path(appCacheDir, appIdStr);
+      Path containerDir = new Path(appDir, containerIdStr);
+      createDir(containerDir, dirPerm, true, userName);
+    }
+
+    // Create the container log-dirs on all disks
+    createContainerLogDirs(appIdStr, containerIdStr, logDirs, userName);
+
+    Path tmpDir = new Path(containerWorkDir,
+        YarnConfiguration.DEFAULT_CONTAINER_TEMP_DIR);
+    createDir(tmpDir, dirPerm, false, userName);
+
+    // copy launch script to work dir
+    Path launchDst =
+        new Path(containerWorkDir, ContainerLaunch.CONTAINER_SCRIPT);
+    lfs.util().copy(nmPrivateContainerScriptPath, launchDst);
+
+    // copy container tokens to work dir
+    Path tokenDst =
+        new Path(containerWorkDir, ContainerLaunch.FINAL_CONTAINER_TOKENS_FILE);
+    lfs.util().copy(nmPrivateTokensPath, tokenDst);
+
+
+
+    String localDirMount = toMount(localDirs);
+    String logDirMount = toMount(logDirs);
+    String containerWorkDirMount = toMount(Collections.singletonList(containerWorkDir.toUri().getPath()));
+    StringBuilder commands = new StringBuilder();
+    String commandStr = commands.append(dockerExecutor)
+        .append(" ")
+        .append("run")
+        .append(" ")
+        .append("--rm --net=host")
+        .append(" ")
+        .append(" --name " + containerIdStr)
+        .append(localDirMount)
+        .append(logDirMount)
+        .append(containerWorkDirMount)
+        .append(" ")
+        .append(containerImageName)
+        .toString();
+    String dockerPidScript = "`" + dockerExecutor + " inspect --format {{.State.Pid}} " + containerIdStr + "`";
+    // Create new local launch wrapper script
+    LocalWrapperScriptBuilder sb =
+      new UnixLocalWrapperScriptBuilder(containerWorkDir, commandStr, dockerPidScript);
+    Path pidFile = getPidFilePath(containerId);
+    if (pidFile != null) {
+      sb.writeLocalWrapperScript(launchDst, pidFile);
+    } else {
+      LOG.info("Container " + containerIdStr
+          + " was marked as inactive. Returning terminated error");
+      return ExitCode.TERMINATED.getExitCode();
+    }
+    
+    ShellCommandExecutor shExec = null;
+    try {
+      lfs.setPermission(launchDst,
+          ContainerExecutor.TASK_LAUNCH_SCRIPT_PERMISSION);
+      lfs.setPermission(sb.getWrapperScriptPath(),
+          ContainerExecutor.TASK_LAUNCH_SCRIPT_PERMISSION);
+
+      // Setup command to run
+      String[] command = getRunCommand(sb.getWrapperScriptPath().toString(),
+        containerIdStr, userName, pidFile, this.getConf());
+      if (LOG.isDebugEnabled()) {
+        LOG.debug("launchContainer: " + commandStr + " " + Joiner.on(" ").join(command));
+      }
+      shExec = new ShellCommandExecutor(
+          command,
+          new File(containerWorkDir.toUri().getPath()),
+          container.getLaunchContext().getEnvironment());      // sanitized env
+      if (isContainerActive(containerId)) {
+        shExec.execute();
+      } else {
+        LOG.info("Container " + containerIdStr +
+            " was marked as inactive. Returning terminated error");
+        return ExitCode.TERMINATED.getExitCode();
+      }
+    } catch (IOException e) {
+      if (null == shExec) {
+        return -1;
+      }
+      int exitCode = shExec.getExitCode();
+      LOG.warn("Exit code from container " + containerId + " is : " + exitCode);
+      // 143 (SIGTERM) and 137 (SIGKILL) exit codes means the container was
+      // terminated/killed forcefully. In all other cases, log the
+      // container-executor's output
+      if (exitCode != ExitCode.FORCE_KILLED.getExitCode()
+          && exitCode != ExitCode.TERMINATED.getExitCode()) {
+        LOG.warn("Exception from container-launch with container ID: "
+            + containerId + " and exit code: " + exitCode, e);
+        logOutput(shExec.getOutput());
+        String diagnostics = "Exception from container-launch: \n"
+            + StringUtils.stringifyException(e) + "\n" + shExec.getOutput();
+        container.handle(new ContainerDiagnosticsUpdateEvent(containerId,
+            diagnostics));
+      } else {
+        container.handle(new ContainerDiagnosticsUpdateEvent(containerId,
+            "Container killed on request. Exit code is " + exitCode));
+      }
+      return exitCode;
+    } finally {
+      if (shExec != null) {
+        shExec.close();
+      }
+    }
+    return 0;
+  }
+
+  @Override
+  public void writeLaunchEnv(OutputStream out, Map<String, String> environment, Map<Path, List<String>> resources, List<String> command) throws IOException {
+    ContainerLaunch.ShellScriptBuilder sb = ContainerLaunch.ShellScriptBuilder.create();
+
+    Set<String> exclusionSet = new HashSet<String>();
+    exclusionSet.add(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME);
+    exclusionSet.add(ApplicationConstants.Environment.HADOOP_YARN_HOME.name());
+    exclusionSet.add(ApplicationConstants.Environment.HADOOP_COMMON_HOME.name());
+    exclusionSet.add(ApplicationConstants.Environment.HADOOP_HDFS_HOME.name());
+    exclusionSet.add(ApplicationConstants.Environment.HADOOP_CONF_DIR.name());
+    exclusionSet.add(ApplicationConstants.Environment.JAVA_HOME.name());
+
+    if (environment != null) {
+      for (Map.Entry<String,String> env : environment.entrySet()) {
+        if (!exclusionSet.contains(env.getKey())) {
+          sb.env(env.getKey().toString(), env.getValue().toString());
+        }
+      }
+    }
+    if (resources != null) {
+      for (Map.Entry<Path,List<String>> entry : resources.entrySet()) {
+        for (String linkName : entry.getValue()) {
+          sb.symlink(entry.getKey(), new Path(linkName));
+        }
+      }
+    }
+
+    sb.command(command);
+
+    PrintStream pout = null;
+    PrintStream ps = null;
+    ByteArrayOutputStream baos = new ByteArrayOutputStream();
+    try {
+      pout = new PrintStream(out);
+      if (LOG.isDebugEnabled()) {
+        ps = new PrintStream(baos);
+        sb.write(ps);
+      }
+      sb.write(pout);
+
+    } finally {
+      if (out != null) {
+        out.close();
+      }
+      if (ps != null) {
+        ps.close();
+      }
+    }
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Script: " + baos.toString());
+    }
+  }
+
+  private boolean saneDockerImage(String containerImageName) {
+    return dockerImagePattern.matcher(containerImageName).matches();
+  }
+
+  @Override
+  public boolean signalContainer(String user, String pid, Signal signal)
+    throws IOException {
+    if (LOG.isDebugEnabled()) {
+      LOG.debug("Sending signal " + signal.getValue() + " to pid " + pid
+        + " as user " + user);
+    }
+    if (!containerIsAlive(pid)) {
+      return false;
+    }
+    try {
+      killContainer(pid, signal);
+    } catch (IOException e) {
+      if (!containerIsAlive(pid)) {
+        return false;
+      }
+      throw e;
+    }
+    return true;
+  }
+
+  @Override
+  public boolean isContainerProcessAlive(String user, String pid)
+    throws IOException {
+    return containerIsAlive(pid);
+  }
+
+  /**
+   * Returns true if the process with the specified pid is alive.
+   *
+   * @param pid String pid
+   * @return boolean true if the process is alive
+   */
+  @VisibleForTesting
+  public static boolean containerIsAlive(String pid) throws IOException {
+    try {
+      new ShellCommandExecutor(Shell.getCheckProcessIsAliveCommand(pid))
+        .execute();
+      // successful execution means process is alive
+      return true;
+    }
+    catch (Shell.ExitCodeException e) {
+      // failure (non-zero exit code) means process is not alive
+      return false;
+    }
+  }
+
+  /**
+   * Send a specified signal to the specified pid
+   *
+   * @param pid the pid of the process [group] to signal.
+   * @param signal signal to send
+   * (for logging).
+   */
+  protected void killContainer(String pid, Signal signal) throws IOException {
+    new ShellCommandExecutor(Shell.getSignalKillCommand(signal.getValue(), pid))
+      .execute();
+  }
+
+  @Override
+  public void deleteAsUser(String user, Path subDir, Path... baseDirs)
+    throws IOException, InterruptedException {
+    if (baseDirs == null || baseDirs.length == 0) {
+      LOG.info("Deleting absolute path : " + subDir);
+      if (!lfs.delete(subDir, true)) {
+        //Maybe retry
+        LOG.warn("delete returned false for path: [" + subDir + "]");
+      }
+      return;
+    }
+    for (Path baseDir : baseDirs) {
+      Path del = subDir == null ? baseDir : new Path(baseDir, subDir);
+      LOG.info("Deleting path : " + del);
+      if (!lfs.delete(del, true)) {
+        LOG.warn("delete returned false for path: [" + del + "]");
+      }
+    }
+  }
+
+  /**
+   * Converts a directory list to a docker mount string
+   * @param dirs
+   * @return a string of mounts for docker
+   */
+  private String toMount(List<String> dirs) {
+    StringBuilder builder = new StringBuilder();
+    for (String dir : dirs) {
+      builder.append(" -v " + dir + ":" + dir);
+    }
+    return builder.toString();
+  }
+
+  private abstract class LocalWrapperScriptBuilder {
+
+    private final Path wrapperScriptPath;
+
+    public Path getWrapperScriptPath() {
+      return wrapperScriptPath;
+    }
+
+    public void writeLocalWrapperScript(Path launchDst, Path pidFile) throws IOException {
+      DataOutputStream out = null;
+      PrintStream pout = null;
+
+      try {
+        out = lfs.create(wrapperScriptPath, EnumSet.of(CREATE, OVERWRITE));
+        pout = new PrintStream(out);
+        writeLocalWrapperScript(launchDst, pidFile, pout);
+      } finally {
+        IOUtils.cleanup(LOG, pout, out);
+      }
+    }
+
+    protected abstract void writeLocalWrapperScript(Path launchDst, Path pidFile,
+                                                    PrintStream pout);
+
+    protected LocalWrapperScriptBuilder(Path containerWorkDir) {
+      this.wrapperScriptPath = new Path(containerWorkDir,
+          Shell.appendScriptExtension(DOCKER_CONTAINER_EXECUTOR_SCRIPT));
+    }
+  }
+
+  private final class UnixLocalWrapperScriptBuilder
+      extends LocalWrapperScriptBuilder {
+    private final Path sessionScriptPath;
+    private final String dockerCommand;
+    private final String dockerPidScript;
+
+    public UnixLocalWrapperScriptBuilder(Path containerWorkDir, String dockerCommand, String dockerPidScript) {
+      super(containerWorkDir);
+      this.dockerCommand = dockerCommand;
+      this.dockerPidScript = dockerPidScript;
+      this.sessionScriptPath = new Path(containerWorkDir,
+        Shell.appendScriptExtension(DOCKER_CONTAINER_EXECUTOR_SESSION_SCRIPT));
+    }
+
+    @Override
+    public void writeLocalWrapperScript(Path launchDst, Path pidFile)
+      throws IOException {
+      writeSessionScript(launchDst, pidFile);
+      super.writeLocalWrapperScript(launchDst, pidFile);
+    }
+
+    @Override
+    public void writeLocalWrapperScript(Path launchDst, Path pidFile,
+                                        PrintStream pout) {
+
+      String exitCodeFile = ContainerLaunch.getExitCodeFile(
+        pidFile.toString());
+      String tmpFile = exitCodeFile + ".tmp";
+      pout.println("#!/usr/bin/env bash");
+      pout.println("bash \"" + sessionScriptPath.toString() + "\"");
+      pout.println("rc=$?");
+      pout.println("echo $rc > \"" + tmpFile + "\"");
+      pout.println("mv -f \"" + tmpFile + "\" \"" + exitCodeFile + "\"");
+      pout.println("exit $rc");
+    }
+
+    private void writeSessionScript(Path launchDst, Path pidFile)
+      throws IOException {
+      DataOutputStream out = null;
+      PrintStream pout = null;
+      try {
+        out = lfs.create(sessionScriptPath, EnumSet.of(CREATE, OVERWRITE));
+        pout = new PrintStream(out);
+        // We need to do a move as writing to a file is not atomic
+        // Process reading a file being written to may get garbled data
+        // hence write pid to tmp file first followed by a mv
+        pout.println("#!/usr/bin/env bash");
+        pout.println();
+        pout.println("echo "+ dockerPidScript +" > " + pidFile.toString() + ".tmp");
+        pout.println("/bin/mv -f " + pidFile.toString() + ".tmp " + pidFile);
+        pout.println(dockerCommand + " bash \"" +
+          launchDst.toUri().getPath().toString() + "\"");
+      } finally {
+        IOUtils.cleanup(LOG, pout, out);
+      }
+      lfs.setPermission(sessionScriptPath,
+        ContainerExecutor.TASK_LAUNCH_SCRIPT_PERMISSION);
+    }
+  }
+
+  protected void createDir(Path dirPath, FsPermission perms,
+                           boolean createParent, String user) throws IOException {
+    lfs.mkdir(dirPath, perms, createParent);
+    if (!perms.equals(perms.applyUMask(lfs.getUMask()))) {
+      lfs.setPermission(dirPath, perms);
+    }
+  }
+
+  /**
+   * Initialize the local directories for a particular user.
+   * <ul>.mkdir
+   * <li>$local.dir/usercache/$user</li>
+   * </ul>
+   */
+  void createUserLocalDirs(List<String> localDirs, String user)
+      throws IOException {
+    boolean userDirStatus = false;
+    FsPermission userperms = new FsPermission(USER_PERM);
+    for (String localDir : localDirs) {
+      // create $local.dir/usercache/$user and its immediate parent
+      try {
+        createDir(getUserCacheDir(new Path(localDir), user), userperms, true, user);
+      } catch (IOException e) {
+        LOG.warn("Unable to create the user directory : " + localDir, e);
+        continue;
+      }
+      userDirStatus = true;
+    }
+    if (!userDirStatus) {
+      throw new IOException("Not able to initialize user directories "
+          + "in any of the configured local directories for user " + user);
+    }
+  }
+
+
+  /**
+   * Initialize the local cache directories for a particular user.
+   * <ul>
+   * <li>$local.dir/usercache/$user</li>
+   * <li>$local.dir/usercache/$user/appcache</li>
+   * <li>$local.dir/usercache/$user/filecache</li>
+   * </ul>
+   */
+  void createUserCacheDirs(List<String> localDirs, String user)
+    throws IOException {
+    LOG.info("Initializing user " + user);
+
+    boolean appcacheDirStatus = false;
+    boolean distributedCacheDirStatus = false;
+    FsPermission appCachePerms = new FsPermission(APPCACHE_PERM);
+    FsPermission fileperms = new FsPermission(FILECACHE_PERM);
+
+    for (String localDir : localDirs) {
+      // create $local.dir/usercache/$user/appcache
+      Path localDirPath = new Path(localDir);
+      final Path appDir = getAppcacheDir(localDirPath, user);
+      try {
+        createDir(appDir, appCachePerms, true, user);
+        appcacheDirStatus = true;
+      } catch (IOException e) {
+        LOG.warn("Unable to create app cache directory : " + appDir, e);
+      }
+      // create $local.dir/usercache/$user/filecache
+      final Path distDir = getFileCacheDir(localDirPath, user);
+      try {
+        createDir(distDir, fileperms, true, user);
+        distributedCacheDirStatus = true;
+      } catch (IOException e) {
+        LOG.warn("Unable to create file cache directory : " + distDir, e);
+      }
+    }
+    if (!appcacheDirStatus) {
+      throw new IOException("Not able to initialize app-cache directories "
+        + "in any of the configured local directories for user " + user);
+    }
+    if (!distributedCacheDirStatus) {
+      throw new IOException(
+        "Not able to initialize distributed-cache directories "
+          + "in any of the configured local directories for user "
+          + user);
+    }
+  }
+
+  /**
+   * Initialize the local directories for a particular user.
+   * <ul>
+   * <li>$local.dir/usercache/$user/appcache/$appid</li>
+   * </ul>
+   * @param localDirs
+   */
+  void createAppDirs(List<String> localDirs, String user, String appId)
+    throws IOException {
+    boolean initAppDirStatus = false;
+    FsPermission appperms = new FsPermission(APPDIR_PERM);
+    for (String localDir : localDirs) {
+      Path fullAppDir = getApplicationDir(new Path(localDir), user, appId);
+      // create $local.dir/usercache/$user/appcache/$appId
+      try {
+        createDir(fullAppDir, appperms, true, user);
+        initAppDirStatus = true;
+      } catch (IOException e) {
+        LOG.warn("Unable to create app directory " + fullAppDir.toString(), e);
+      }
+    }
+    if (!initAppDirStatus) {
+      throw new IOException("Not able to initialize app directories "
+        + "in any of the configured local directories for app "
+        + appId.toString());
+    }
+  }
+
+
+  /**
+   * Create application log directories on all disks.
+   */
+  void createContainerLogDirs(String appId, String containerId,
+                              List<String> logDirs, String user) throws IOException {
+
+    boolean containerLogDirStatus = false;
+    FsPermission containerLogDirPerms = new FsPermission(LOGDIR_PERM);
+    for (String rootLogDir : logDirs) {
+      // create $log.dir/$appid/$containerid
+      Path appLogDir = new Path(rootLogDir, appId);
+      Path containerLogDir = new Path(appLogDir, containerId);
+      try {
+        createDir(containerLogDir, containerLogDirPerms, true, user);
+      } catch (IOException e) {
+        LOG.warn("Unable to create the container-log directory : "
+          + appLogDir, e);
+        continue;
+      }
+      containerLogDirStatus = true;
+    }
+    if (!containerLogDirStatus) {
+      throw new IOException(
+        "Not able to initialize container-log directories "
+          + "in any of the configured local directories for container "
+          + containerId);
+    }
+  }
+
+  /**
+   * Permissions for user dir.
+   * $local.dir/usercache/$user
+   */
+  static final short USER_PERM = (short) 0750;
+  /**
+   * Permissions for user appcache dir.
+   * $local.dir/usercache/$user/appcache
+   */
+  static final short APPCACHE_PERM = (short) 0710;
+  /**
+   * Permissions for user filecache dir.
+   * $local.dir/usercache/$user/filecache
+   */
+  static final short FILECACHE_PERM = (short) 0710;
+  /**
+   * Permissions for user app dir.
+   * $local.dir/usercache/$user/appcache/$appId
+   */
+  static final short APPDIR_PERM = (short) 0710;
+  /**
+   * Permissions for user log dir.
+   * $logdir/$user/$appId
+   */
+  static final short LOGDIR_PERM = (short) 0710;
+
+  private long getDiskFreeSpace(Path base) throws IOException {
+    return lfs.getFsStatus(base).getRemaining();
+  }
+
+  private Path getApplicationDir(Path base, String user, String appId) {
+    return new Path(getAppcacheDir(base, user), appId);
+  }
+
+  private Path getUserCacheDir(Path base, String user) {
+    return new Path(new Path(base, ContainerLocalizer.USERCACHE), user);
+  }
+
+  private Path getAppcacheDir(Path base, String user) {
+    return new Path(getUserCacheDir(base, user),
+        ContainerLocalizer.APPCACHE);
+  }
+
+  private Path getFileCacheDir(Path base, String user) {
+    return new Path(getUserCacheDir(base, user),
+        ContainerLocalizer.FILECACHE);
+  }
+
+  protected Path getWorkingDir(List<String> localDirs, String user,
+                               String appId) throws IOException {
+    Path appStorageDir = null;
+    long totalAvailable = 0L;
+    long[] availableOnDisk = new long[localDirs.size()];
+    int i = 0;
+    // randomly choose the app directory
+    // the chance of picking a directory is proportional to
+    // the available space on the directory.
+    // firstly calculate the sum of all available space on these directories
+    for (String localDir : localDirs) {
+      Path curBase = getApplicationDir(new Path(localDir),
+        user, appId);
+      long space = 0L;
+      try {
+        space = getDiskFreeSpace(curBase);
+      } catch (IOException e) {
+        LOG.warn("Unable to get Free Space for " + curBase.toString(), e);
+      }
+      availableOnDisk[i++] = space;
+      totalAvailable += space;
+    }
+
+    // throw an IOException if totalAvailable is 0.
+    if (totalAvailable <= 0L) {
+      throw new IOException("Not able to find a working directory for "
+        + user);
+    }
+
+    // make probability to pick a directory proportional to
+    // the available space on the directory.
+    Random r = new Random();
+    long randomPosition = Math.abs(r.nextLong()) % totalAvailable;
+    int dir = 0;
+    // skip zero available space directory,
+    // because totalAvailable is greater than 0 and randomPosition
+    // is less than totalAvailable, we can find a valid directory
+    // with nonzero available space.
+    while (availableOnDisk[dir] == 0L) {
+      dir++;
+    }
+    while (randomPosition > availableOnDisk[dir]) {
+      randomPosition -= availableOnDisk[dir++];
+    }
+    appStorageDir = getApplicationDir(new Path(localDirs.get(dir)),
+      user, appId);
+
+    return appStorageDir;
+  }
+
+  /**
+   * Create application log directories on all disks.
+   */
+  void createAppLogDirs(String appId, List<String> logDirs, String user)
+    throws IOException {
+
+    boolean appLogDirStatus = false;
+    FsPermission appLogDirPerms = new FsPermission(LOGDIR_PERM);
+    for (String rootLogDir : logDirs) {
+      // create $log.dir/$appid
+      Path appLogDir = new Path(rootLogDir, appId);
+      try {
+        createDir(appLogDir, appLogDirPerms, true, user);
+      } catch (IOException e) {
+        LOG.warn("Unable to create the app-log directory : " + appLogDir, e);
+        continue;
+      }
+      appLogDirStatus = true;
+    }
+    if (!appLogDirStatus) {
+      throw new IOException("Not able to initialize app-log directories "
+        + "in any of the configured local directories for app " + appId);
+    }
+  }
+
+  /**
+   * @return the list of paths of given local directories
+   */
+  private static List<Path> getPaths(List<String> dirs) {
+    List<Path> paths = new ArrayList<Path>(dirs.size());
+    for (int i = 0; i < dirs.size(); i++) {
+      paths.add(new Path(dirs.get(i)));
+    }
+    return paths;
+  }
+
+}
\ No newline at end of file

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/ContainerLaunch.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/ContainerLaunch.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/ContainerLaunch.java
index 8fc5ea3..a87238d 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/ContainerLaunch.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/main/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/ContainerLaunch.java
@@ -269,7 +269,7 @@ public class ContainerLaunch implements Callable<Integer> {
           localResources, nmPrivateClasspathJarDir);
         
         // Write out the environment
-        writeLaunchEnv(containerScriptOutStream, environment, localResources,
+        exec.writeLaunchEnv(containerScriptOutStream, environment, localResources,
             launchContext.getCommands());
         
         // /////////// End of writing out container-script
@@ -502,8 +502,7 @@ public class ContainerLaunch implements Callable<Integer> {
     return context;
   }
 
-  @VisibleForTesting
-  static abstract class ShellScriptBuilder {
+  public static abstract class ShellScriptBuilder {
     public static ShellScriptBuilder create() {
       return Shell.WINDOWS ? new WindowsShellScriptBuilder() :
         new UnixShellScriptBuilder();
@@ -793,37 +792,6 @@ public class ContainerLaunch implements Callable<Integer> {
           meta.getKey(), meta.getValue(), environment);
     }
   }
-    
-  static void writeLaunchEnv(OutputStream out,
-      Map<String,String> environment, Map<Path,List<String>> resources,
-      List<String> command)
-      throws IOException {
-    ShellScriptBuilder sb = ShellScriptBuilder.create();
-    if (environment != null) {
-      for (Map.Entry<String,String> env : environment.entrySet()) {
-        sb.env(env.getKey().toString(), env.getValue().toString());
-      }
-    }
-    if (resources != null) {
-      for (Map.Entry<Path,List<String>> entry : resources.entrySet()) {
-        for (String linkName : entry.getValue()) {
-          sb.symlink(entry.getKey(), new Path(linkName));
-        }
-      }
-    }
-
-    sb.command(command);
-
-    PrintStream pout = null;
-    try {
-      pout = new PrintStream(out);
-      sb.write(pout);
-    } finally {
-      if (out != null) {
-        out.close();
-      }
-    }
-  }
 
   public static String getExitCodeFile(String pidFile) {
     return pidFile + EXIT_CODE_FILE_SUFFIX;

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutor.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutor.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutor.java
new file mode 100644
index 0000000..e43ac2e
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutor.java
@@ -0,0 +1,213 @@
+/**
+ * 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.yarn.server.nodemanager;
+
+import com.google.common.base.Strings;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FileContext;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.util.Shell;
+import org.apache.hadoop.yarn.api.ApplicationConstants;
+import org.apache.hadoop.yarn.api.records.ContainerId;
+import org.apache.hadoop.yarn.api.records.ContainerLaunchContext;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.Container;
+import org.apache.hadoop.yarn.util.ConverterUtils;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.LineNumberReader;
+import java.io.PrintWriter;
+import java.util.ArrayList;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeTrue;
+import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * This is intended to test the DockerContainerExecutor code, but it requires docker
+ * to be installed.
+ * <br><ol>
+ * <li>Install docker, and Compile the code with docker-service-url set to the host and port
+ * where docker service is running.
+ * <br><pre><code>
+ * > mvn clean install -Ddocker-service-url=tcp://0.0.0.0:4243
+ *                          -DskipTests
+ * </code></pre>
+ */
+public class TestDockerContainerExecutor {
+  private static final Log LOG = LogFactory
+      .getLog(TestDockerContainerExecutor.class);
+  private static File workSpace = null;
+  private DockerContainerExecutor exec = null;
+  private LocalDirsHandlerService dirsHandler;
+  private Path workDir;
+  private FileContext lfs;
+  private String yarnImage;
+
+  private int id = 0;
+  private String appSubmitter;
+  private String dockerUrl;
+  private String testImage = "centos";
+  private String dockerExec;
+  private String containerIdStr;
+
+
+  private ContainerId getNextContainerId() {
+    ContainerId cId = mock(ContainerId.class, RETURNS_DEEP_STUBS);
+    String id = "CONTAINER_" + System.currentTimeMillis();
+    when(cId.toString()).thenReturn(id);
+    return cId;
+  }
+
+  @Before
+  public void setup() {
+    try {
+      lfs = FileContext.getLocalFSFileContext();
+      workDir = new Path("/tmp/temp-" + System.currentTimeMillis());
+      workSpace = new File(workDir.toUri().getPath());
+      lfs.mkdir(workDir, FsPermission.getDirDefault(), true);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+    Configuration conf = new Configuration();
+    yarnImage = "yarnImage";
+    long time = System.currentTimeMillis();
+    conf.set(YarnConfiguration.NM_LOCAL_DIRS, "/tmp/nm-local-dir" + time);
+    conf.set(YarnConfiguration.NM_LOG_DIRS, "/tmp/userlogs" + time);
+
+    dockerUrl = System.getProperty("docker-service-url");
+    LOG.info("dockerUrl: " + dockerUrl);
+    if (Strings.isNullOrEmpty(dockerUrl)) {
+      return;
+    }
+    dockerUrl = " -H " + dockerUrl;
+    dockerExec = "docker " + dockerUrl;
+    conf.set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, yarnImage);
+    conf.set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME, dockerExec);
+    exec = new DockerContainerExecutor();
+    dirsHandler = new LocalDirsHandlerService();
+    dirsHandler.init(conf);
+    exec.setConf(conf);
+    appSubmitter = System.getProperty("application.submitter");
+    if (appSubmitter == null || appSubmitter.isEmpty()) {
+      appSubmitter = "nobody";
+    }
+    shellExec(dockerExec + " pull " + testImage);
+
+  }
+
+  private Shell.ShellCommandExecutor shellExec(String command) {
+    try {
+
+      Shell.ShellCommandExecutor shExec = new Shell.ShellCommandExecutor(
+          command.split("\\s+"),
+          new File(workDir.toUri().getPath()),
+          System.getenv());
+      shExec.execute();
+      return shExec;
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  private boolean shouldRun() {
+    return exec != null;
+  }
+
+  private int runAndBlock(ContainerId cId, Map<String, String> launchCtxEnv, String... cmd) throws IOException {
+    String appId = "APP_" + System.currentTimeMillis();
+    Container container = mock(Container.class);
+    ContainerLaunchContext context = mock(ContainerLaunchContext.class);
+
+    when(container.getContainerId()).thenReturn(cId);
+    when(container.getLaunchContext()).thenReturn(context);
+    when(cId.getApplicationAttemptId().getApplicationId().toString()).thenReturn(appId);
+    when(context.getEnvironment()).thenReturn(launchCtxEnv);
+
+    String script = writeScriptFile(launchCtxEnv, cmd);
+
+    Path scriptPath = new Path(script);
+    Path tokensPath = new Path("/dev/null");
+    Path workDir = new Path(workSpace.getAbsolutePath());
+    Path pidFile = new Path(workDir, "pid.txt");
+
+    exec.activateContainer(cId, pidFile);
+    return exec.launchContainer(container, scriptPath, tokensPath,
+        appSubmitter, appId, workDir, dirsHandler.getLocalDirs(),
+        dirsHandler.getLogDirs());
+  }
+
+  private String writeScriptFile(Map<String, String> launchCtxEnv, String... cmd) throws IOException {
+    File f = File.createTempFile("TestDockerContainerExecutor", ".sh");
+    f.deleteOnExit();
+    PrintWriter p = new PrintWriter(new FileOutputStream(f));
+    for(Map.Entry<String, String> entry: launchCtxEnv.entrySet()) {
+      p.println("export " + entry.getKey() + "=\"" + entry.getValue() + "\"");
+    }
+    for (String part : cmd) {
+      p.print(part.replace("\\", "\\\\").replace("'", "\\'"));
+      p.print(" ");
+    }
+    p.println();
+    p.close();
+    return f.getAbsolutePath();
+  }
+
+  @After
+  public void tearDown() {
+    try {
+      lfs.delete(workDir, true);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Test
+  public void testLaunchContainer() throws IOException {
+    if (!shouldRun()) {
+      LOG.warn("Docker not installed, aborting test.");
+      return;
+    }
+
+    Map<String, String> env = new HashMap<String, String>();
+    env.put(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    String touchFileName = "touch-file-" + System.currentTimeMillis();
+    File touchFile = new File(dirsHandler.getLocalDirs().get(0), touchFileName);
+    ContainerId cId = getNextContainerId();
+    int ret = runAndBlock(
+        cId, env, "touch", touchFile.getAbsolutePath(), "&&", "cp", touchFile.getAbsolutePath(), "/");
+
+    assertEquals(0, ret);
+  }
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutorWithMocks.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutorWithMocks.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutorWithMocks.java
new file mode 100644
index 0000000..fa8bfaf
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/TestDockerContainerExecutorWithMocks.java
@@ -0,0 +1,259 @@
+/**
+ * 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.yarn.server.nodemanager;
+
+import com.google.common.base.Strings;
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.CommonConfigurationKeys;
+import org.apache.hadoop.fs.FileContext;
+import org.apache.hadoop.fs.FileUtil;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.util.Shell;
+import org.apache.hadoop.yarn.api.records.ContainerId;
+import org.apache.hadoop.yarn.api.records.ContainerLaunchContext;
+import org.apache.hadoop.yarn.conf.YarnConfiguration;
+import org.apache.hadoop.yarn.server.nodemanager.containermanager.container.Container;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileReader;
+import java.io.IOException;
+import java.io.LineNumberReader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.List;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assume.assumeTrue;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.RETURNS_DEEP_STUBS;
+
+/**
+ * Mock tests for docker container executor
+ */
+public class TestDockerContainerExecutorWithMocks {
+
+  private static final Log LOG = LogFactory
+      .getLog(TestDockerContainerExecutorWithMocks.class);
+  public static final String DOCKER_LAUNCH_COMMAND = "/bin/true";
+  private DockerContainerExecutor dockerContainerExecutor = null;
+  private LocalDirsHandlerService dirsHandler;
+  private Path workDir;
+  private FileContext lfs;
+  private String yarnImage;
+
+  @Before
+  public void setup() {
+    assumeTrue(!Path.WINDOWS);
+    File f = new File("./src/test/resources/mock-container-executor");
+    if(!FileUtil.canExecute(f)) {
+      FileUtil.setExecutable(f, true);
+    }
+    String executorPath = f.getAbsolutePath();
+    Configuration conf = new Configuration();
+    yarnImage = "yarnImage";
+    long time = System.currentTimeMillis();
+    conf.set(YarnConfiguration.NM_LINUX_CONTAINER_EXECUTOR_PATH, executorPath);
+    conf.set(YarnConfiguration.NM_LOCAL_DIRS, "/tmp/nm-local-dir" + time);
+    conf.set(YarnConfiguration.NM_LOG_DIRS, "/tmp/userlogs" + time);
+    conf.set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, yarnImage);
+    conf.set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_EXEC_NAME , DOCKER_LAUNCH_COMMAND);
+    dockerContainerExecutor = new DockerContainerExecutor();
+    dirsHandler = new LocalDirsHandlerService();
+    dirsHandler.init(conf);
+    dockerContainerExecutor.setConf(conf);
+    lfs = null;
+    try {
+      lfs = FileContext.getLocalFSFileContext();
+      workDir = new Path("/tmp/temp-"+ System.currentTimeMillis());
+      lfs.mkdir(workDir, FsPermission.getDirDefault(), true);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+
+  }
+
+  @After
+  public void tearDown() {
+    try {
+      lfs.delete(workDir, true);
+    } catch (IOException e) {
+      throw new RuntimeException(e);
+    }
+  }
+
+  @Test(expected = IllegalStateException.class)
+  public void testContainerInitSecure() throws IOException {
+    dockerContainerExecutor.getConf().set(
+        CommonConfigurationKeys.HADOOP_SECURITY_AUTHENTICATION, "kerberos");
+    dockerContainerExecutor.init();
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testContainerLaunchNullImage() throws IOException {
+    String appSubmitter = "nobody";
+    String appId = "APP_ID";
+    String containerId = "CONTAINER_ID";
+    String testImage = "";
+
+    Container container = mock(Container.class, RETURNS_DEEP_STUBS);
+    ContainerId cId = mock(ContainerId.class, RETURNS_DEEP_STUBS);
+    ContainerLaunchContext context = mock(ContainerLaunchContext.class);
+    HashMap<String, String> env = new HashMap<String,String>();
+
+    when(container.getContainerId()).thenReturn(cId);
+    when(container.getLaunchContext()).thenReturn(context);
+    when(cId.getApplicationAttemptId().getApplicationId().toString()).thenReturn(appId);
+    when(cId.toString()).thenReturn(containerId);
+
+    when(context.getEnvironment()).thenReturn(env);
+    env.put(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    dockerContainerExecutor.getConf()
+        .set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    Path scriptPath = new Path("file:///bin/echo");
+    Path tokensPath = new Path("file:///dev/null");
+
+    Path pidFile = new Path(workDir, "pid.txt");
+
+    dockerContainerExecutor.activateContainer(cId, pidFile);
+    dockerContainerExecutor.launchContainer(container, scriptPath, tokensPath,
+        appSubmitter, appId, workDir, dirsHandler.getLocalDirs(),
+        dirsHandler.getLogDirs());
+  }
+
+  @Test(expected = IllegalArgumentException.class)
+  public void testContainerLaunchInvalidImage() throws IOException {
+    String appSubmitter = "nobody";
+    String appId = "APP_ID";
+    String containerId = "CONTAINER_ID";
+    String testImage = "testrepo.com/test-image rm -rf $HADOOP_PREFIX/*";
+
+    Container container = mock(Container.class, RETURNS_DEEP_STUBS);
+    ContainerId cId = mock(ContainerId.class, RETURNS_DEEP_STUBS);
+    ContainerLaunchContext context = mock(ContainerLaunchContext.class);
+    HashMap<String, String> env = new HashMap<String,String>();
+
+    when(container.getContainerId()).thenReturn(cId);
+    when(container.getLaunchContext()).thenReturn(context);
+    when(cId.getApplicationAttemptId().getApplicationId().toString()).thenReturn(appId);
+    when(cId.toString()).thenReturn(containerId);
+
+    when(context.getEnvironment()).thenReturn(env);
+    env.put(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    dockerContainerExecutor.getConf()
+      .set(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    Path scriptPath = new Path("file:///bin/echo");
+    Path tokensPath = new Path("file:///dev/null");
+
+    Path pidFile = new Path(workDir, "pid.txt");
+
+    dockerContainerExecutor.activateContainer(cId, pidFile);
+    dockerContainerExecutor.launchContainer(container, scriptPath, tokensPath,
+      appSubmitter, appId, workDir, dirsHandler.getLocalDirs(),
+      dirsHandler.getLogDirs());
+  }
+
+  @Test
+  public void testContainerLaunch() throws IOException {
+    String appSubmitter = "nobody";
+    String appId = "APP_ID";
+    String containerId = "CONTAINER_ID";
+    String testImage = "\"sequenceiq/hadoop-docker:2.4.1\"";
+
+    Container container = mock(Container.class, RETURNS_DEEP_STUBS);
+    ContainerId cId = mock(ContainerId.class, RETURNS_DEEP_STUBS);
+    ContainerLaunchContext context = mock(ContainerLaunchContext.class);
+    HashMap<String, String> env = new HashMap<String,String>();
+
+    when(container.getContainerId()).thenReturn(cId);
+    when(container.getLaunchContext()).thenReturn(context);
+    when(cId.getApplicationAttemptId().getApplicationId().toString()).thenReturn(appId);
+    when(cId.toString()).thenReturn(containerId);
+
+    when(context.getEnvironment()).thenReturn(env);
+    env.put(YarnConfiguration.NM_DOCKER_CONTAINER_EXECUTOR_IMAGE_NAME, testImage);
+    Path scriptPath = new Path("file:///bin/echo");
+    Path tokensPath = new Path("file:///dev/null");
+
+    Path pidFile = new Path(workDir, "pid");
+
+    dockerContainerExecutor.activateContainer(cId, pidFile);
+    int ret = dockerContainerExecutor.launchContainer(container, scriptPath, tokensPath,
+        appSubmitter, appId, workDir, dirsHandler.getLocalDirs(),
+        dirsHandler.getLogDirs());
+    assertEquals(0, ret);
+    //get the script
+    Path sessionScriptPath = new Path(workDir,
+        Shell.appendScriptExtension(
+            DockerContainerExecutor.DOCKER_CONTAINER_EXECUTOR_SESSION_SCRIPT));
+    LineNumberReader lnr = new LineNumberReader(new FileReader(sessionScriptPath.toString()));
+    boolean cmdFound = false;
+    List<String> localDirs = dirsToMount(dirsHandler.getLocalDirs());
+    List<String> logDirs = dirsToMount(dirsHandler.getLogDirs());
+    List<String> workDirMount = dirsToMount(Collections.singletonList(workDir.toUri().getPath()));
+    List<String> expectedCommands =  new ArrayList<String>(
+        Arrays.asList(DOCKER_LAUNCH_COMMAND, "run", "--rm", "--net=host",  "--name", containerId));
+    expectedCommands.addAll(localDirs);
+    expectedCommands.addAll(logDirs);
+    expectedCommands.addAll(workDirMount);
+    String shellScript =  workDir + "/launch_container.sh";
+
+    expectedCommands.addAll(Arrays.asList(testImage.replaceAll("['\"]", ""), "bash","\"" + shellScript + "\""));
+
+    String expectedPidString = "echo `/bin/true inspect --format {{.State.Pid}} " + containerId+"` > "+ pidFile.toString() + ".tmp";
+    boolean pidSetterFound = false;
+    while(lnr.ready()){
+      String line = lnr.readLine();
+      LOG.debug("line: " + line);
+      if (line.startsWith(DOCKER_LAUNCH_COMMAND)){
+        List<String> command = new ArrayList<String>();
+        for( String s :line.split("\\s+")){
+          command.add(s.trim());
+        }
+
+        assertEquals(expectedCommands, command);
+        cmdFound = true;
+      } else if (line.startsWith("echo")) {
+        assertEquals(expectedPidString, line);
+        pidSetterFound = true;
+      }
+
+    }
+    assertTrue(cmdFound);
+    assertTrue(pidSetterFound);
+  }
+
+  private List<String> dirsToMount(List<String> dirs) {
+    List<String> localDirs = new ArrayList<String>();
+    for(String dir: dirs){
+      localDirs.add("-v");
+      localDirs.add(dir + ":" + dir);
+    }
+    return localDirs;
+  }
+}

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/TestContainerLaunch.java
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/TestContainerLaunch.java b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/TestContainerLaunch.java
index cbc41c4..4088c2a 100644
--- a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/TestContainerLaunch.java
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-nodemanager/src/test/java/org/apache/hadoop/yarn/server/nodemanager/containermanager/launcher/TestContainerLaunch.java
@@ -75,6 +75,7 @@ import org.apache.hadoop.yarn.event.Event;
 import org.apache.hadoop.yarn.event.EventHandler;
 import org.apache.hadoop.yarn.security.ContainerTokenIdentifier;
 import org.apache.hadoop.yarn.server.api.protocolrecords.NMContainerStatus;
+import org.apache.hadoop.yarn.server.nodemanager.ContainerExecutor;
 import org.apache.hadoop.yarn.server.nodemanager.ContainerExecutor.ExitCode;
 import org.apache.hadoop.yarn.server.nodemanager.DefaultContainerExecutor;
 import org.apache.hadoop.yarn.server.nodemanager.containermanager.BaseContainerManagerTest;
@@ -144,7 +145,7 @@ public class TestContainerLaunch extends BaseContainerManagerTest {
         commands.add("/bin/sh ./\\\"" + badSymlink + "\\\"");
       }
 
-      ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+      new DefaultContainerExecutor().writeLaunchEnv(fos, env, resources, commands);
       fos.flush();
       fos.close();
       FileUtil.setExecutable(tempFile, true);
@@ -211,7 +212,7 @@ public class TestContainerLaunch extends BaseContainerManagerTest {
       } else {
         commands.add("/bin/sh ./\\\"" + symLink + "\\\"");
       }
-      ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+      new DefaultContainerExecutor().writeLaunchEnv(fos, env, resources, commands);
       fos.flush();
       fos.close();
       FileUtil.setExecutable(tempFile, true);
@@ -264,7 +265,7 @@ public class TestContainerLaunch extends BaseContainerManagerTest {
           "\"workflowName\":\"\n\ninsert table " +
           "\npartition (cd_education_status)\nselect cd_demo_sk, cd_gender, " );
       List<String> commands = new ArrayList<String>();
-      ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+      new DefaultContainerExecutor().writeLaunchEnv(fos, env, resources, commands);
       fos.flush();
       fos.close();
 
@@ -341,7 +342,8 @@ public class TestContainerLaunch extends BaseContainerManagerTest {
       Map<String, String> env = new HashMap<String, String>();
       List<String> commands = new ArrayList<String>();
       commands.add(command);
-      ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+      ContainerExecutor exec = new DefaultContainerExecutor();
+      exec.writeLaunchEnv(fos, env, resources, commands);
       fos.flush();
       fos.close();
 

http://git-wip-us.apache.org/repos/asf/hadoop/blob/53f64ee5/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/DockerContainerExecutor.apt.vm
----------------------------------------------------------------------
diff --git a/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/DockerContainerExecutor.apt.vm b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/DockerContainerExecutor.apt.vm
new file mode 100644
index 0000000..4573173
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/DockerContainerExecutor.apt.vm
@@ -0,0 +1,200 @@
+
+~~ Licensed 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. See accompanying LICENSE file.
+
+  ---
+  Hadoop Map Reduce Next Generation-${project.version} - Docker Container Executor
+  ---
+  ---
+  ${maven.build.timestamp}
+
+Docker Container Executor
+
+%{toc|section=1|fromDepth=0}
+
+* {Overview}
+
+    Docker (https://www.docker.io/) combines an easy-to-use interface to
+Linux containers with easy-to-construct image files for those
+containers.  In short, Docker launches very light weight virtual
+machines.
+
+    The Docker Container Executor (DCE) allows the YARN NodeManager to
+launch YARN containers into Docker containers.  Users can specify the
+Docker images they want for their YARN containers.  These containers
+provide a custom software environment in which the user's code runs,
+isolated from the software environment of the NodeManager.  These
+containers can include special libraries needed by the application,
+and they can have different versions of Perl, Python, and even Java
+than what is installed on the NodeManager.  Indeed, these containers
+can run a different flavor of Linux than what is running on the
+NodeManager -- although the YARN container must define all the environments
+ and libraries needed to run the job, nothing will be shared with the NodeManager.
+
+   Docker for YARN provides both consistency (all YARN containers will
+have the same software environment) and isolation (no interference
+with whatever is installed on the physical machine).
+  
+* {Cluster Configuration}
+
+    Docker Container Executor runs in non-secure mode of HDFS and
+YARN. It will not run in secure mode, and will exit if it detects
+secure mode.
+
+    The DockerContainerExecutor requires Docker daemon to be running on
+the NodeManagers, and the Docker client installed and able to start Docker
+containers.  To prevent timeouts while starting jobs, the Docker
+images to be used by a job should already be downloaded in the
+NodeManagers. Here's an example of how this can be done:
+
+----
+sudo docker pull sequenceiq/hadoop-docker:2.4.1
+----
+
+   This should be done as part of the NodeManager startup.
+
+   The following properties must be set in yarn-site.xml:
+
+----
+<property>
+ <name>yarn.nodemanager.docker-container-executor.exec-name</name>
+  <value>/usr/bin/docker</value>
+  <description>
+     Name or path to the Docker client. This is a required parameter. If this is empty,
+     user must pass an image name as part of the job invocation(see below).
+  </description>
+</property>
+
+<property>
+  <name>yarn.nodemanager.container-executor.class</name>
+  <value>org.apache.hadoop.yarn.server.nodemanager.DockerContainerExecutor</value>
+  <description>
+     This is the container executor setting that ensures that all
+jobs are started with the DockerContainerExecutor.
+  </description>
+</property>
+----
+
+   Administrators should be aware that DCE doesn't currently provide
+user name-space isolation.  This means, in particular, that software
+running as root in the YARN container will have root privileges in the
+underlying NodeManager.  Put differently, DCE currently provides no
+better security guarantees than YARN's Default Container Executor. In
+fact, DockerContainerExecutor will exit if it detects secure yarn.
+
+* {Tips for connecting to a secure docker repository}
+
+   By default, docker images are pulled from the docker public repository. The
+format of a docker image url is: <username>/<image_name>. For example,
+sequenceiq/hadoop-docker:2.4.1 is an image in docker public repository that contains java and
+hadoop.
+
+   If you want your own private repository, you provide the repository url instead of
+your username. Therefore, the image url becomes: <private_repo_url>/<image_name>.
+For example, if your repository is on localhost:8080, your images would be like:
+ localhost:8080/hadoop-docker
+
+   To connect to a secure docker repository, you can use the following invocation:
+
+----
+docker login [OPTIONS] [SERVER]
+
+Register or log in to a Docker registry server, if no server is specified
+"https://index.docker.io/v1/" is the default.
+
+-e, --email=""       Email
+-p, --password=""    Password
+-u, --username=""    Username
+----
+
+   If you want to login to a self-hosted registry you can specify this by adding
+the server name.
+
+----
+docker login <private_repo_url>
+----
+
+   This needs to be run as part of the NodeManager startup, or as a cron job if
+the login session expires periodically. You can login to multiple docker repositories
+from the same NodeManager, but all your users will have access to all your repositories,
+as at present the DockerContainerExecutor does not support per-job docker login.
+
+* {Job Configuration}
+
+   Currently you cannot configure any of the Docker settings with the job configuration.
+You can provide Mapper, Reducer, and ApplicationMaster environment overrides for the
+docker images, using the following 3 JVM properties respectively(only for MR jobs):
+  * mapreduce.map.env: You can override the mapper's image by passing 
+yarn.nodemanager.docker-container-executor.image-name=<your_image_name>
+to this JVM property.
+  * mapreduce.reduce.env: You can override the reducer's image by passing
+yarn.nodemanager.docker-container-executor.image-name=<your_image_name>
+to this JVM property.
+  * yarn.app.mapreduce.am.env: You can override the ApplicationMaster's image
+by passing yarn.nodemanager.docker-container-executor.image-name=<your_image_name>
+to this JVM property.
+
+* {Docker Image requirements}
+
+   The Docker Images used for YARN containers must meet the following
+requirements:
+
+   The distro and version of Linux in your Docker Image can be quite different 
+from that of your NodeManager.  (Docker does have a few limitations in this 
+regard, but you're not likely to hit them.)  However, if you're using the 
+MapReduce framework, then your image will need to be configured for running 
+Hadoop. Java must be installed in the container, and the following environment variables
+must be defined in the image: JAVA_HOME, HADOOP_COMMON_PATH, HADOOP_HDFS_HOME,
+HADOOP_MAPRED_HOME, HADOOP_YARN_HOME, and HADOOP_CONF_DIR
+
+
+* {Working example of yarn launched docker containers.}
+
+  The following example shows how to run teragen using DockerContainerExecutor.
+
+  * First ensure that YARN is properly configured with DockerContainerExecutor(see above).
+
+----
+<property>
+ <name>yarn.nodemanager.docker-container-executor.exec-name</name>
+  <value>docker -H=tcp://0.0.0.0:4243</value>
+  <description>
+     Name or path to the Docker client. The tcp socket must be
+     where docker daemon is listening.
+  </description>
+</property>
+
+<property>
+  <name>yarn.nodemanager.container-executor.class</name>
+  <value>org.apache.hadoop.yarn.server.nodemanager.DockerContainerExecutor</value>
+  <description>
+     This is the container executor setting that ensures that all
+jobs are started with the DockerContainerExecutor.
+  </description>
+</property>
+----
+
+  * Pick a custom Docker image if you want. In this example, we'll use sequenceiq/hadoop-docker:2.4.1 from the
+docker hub repository. It has jdk, hadoop, and all the previously mentioned environment variables configured.
+  * Run:
+
+----
+hadoop jar $HADOOP_INSTALLATION_DIR/share/hadoop/mapreduce/hadoop-mapreduce-examples-*.jar \
+teragen \
+-Dmapreduce.map.env="yarn.nodemanager.docker-container-executor.image-name=sequenceiq/hadoop-docker:2.4.1" \
+-Dyarn.app.mapreduce.am.env="yarn.nodemanager.docker-container-executor.image-name=sequenceiq/hadoop-docker:2.4.1" \
+1000 \
+teragen_out_dir
+----
+
+  Once it succeeds, you can check the yarn debug logs to verify that docker indeed has launched containers.
+


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