Install docker, and Compile the code with docker-service-url set to the host and port
+ * where docker service is running.
+ *
+ * > mvn clean install -Ddocker-service-url=tcp://0.0.0.0:4243
+ * -DskipTests
+ *
+ */
+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 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 launchCtxEnv, String... cmd) throws IOException {
+ File f = File.createTempFile("TestDockerContainerExecutor", ".sh");
+ f.deleteOnExit();
+ PrintWriter p = new PrintWriter(new FileOutputStream(f));
+ for(Map.Entry 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 env = new HashMap();
+ 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);
+ }
+}
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 0000000000000..fa8bfaf8dc61b
--- /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 env = new HashMap();
+
+ 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 env = new HashMap();
+
+ 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 env = new HashMap();
+
+ 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 localDirs = dirsToMount(dirsHandler.getLocalDirs());
+ List logDirs = dirsToMount(dirsHandler.getLogDirs());
+ List workDirMount = dirsToMount(Collections.singletonList(workDir.toUri().getPath()));
+ List expectedCommands = new ArrayList(
+ 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 command = new ArrayList();
+ 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 dirsToMount(List dirs) {
+ List localDirs = new ArrayList();
+ for(String dir: dirs){
+ localDirs.add("-v");
+ localDirs.add(dir + ":" + dir);
+ }
+ return localDirs;
+ }
+}
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 cbc41c411ed3e..4088c2ad11a9b 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.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 void testSpecialCharSymlinks() throws IOException {
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 void testInvalidSymlinkDiagnostics() throws IOException {
} 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 void testInvalidEnvSyntaxDiagnostics() throws IOException {
"\"workflowName\":\"\n\ninsert table " +
"\npartition (cd_education_status)\nselect cd_demo_sk, cd_gender, " );
List commands = new ArrayList();
- ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+ new DefaultContainerExecutor().writeLaunchEnv(fos, env, resources, commands);
fos.flush();
fos.close();
@@ -341,7 +342,8 @@ public void testContainerLaunchStdoutAndStderrDiagnostics() throws IOException {
Map env = new HashMap();
List commands = new ArrayList();
commands.add(command);
- ContainerLaunch.writeLaunchEnv(fos, env, resources, commands);
+ ContainerExecutor exec = new DefaultContainerExecutor();
+ exec.writeLaunchEnv(fos, env, resources, commands);
fos.flush();
fos.close();
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 0000000000000..05ddb3705ded8
--- /dev/null
+++ b/hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/DockerContainerExecutor.apt.vm
@@ -0,0 +1,204 @@
+
+~~ 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:
+
+----
+
+ yarn.nodemanager.docker-container-executor.exec-name
+ /usr/bin/docker
+
+ 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).
+
+
+
+
+ yarn.nodemanager.container-executor.class
+ org.apache.hadoop.yarn.server.nodemanager.DockerContainerExecutor
+
+ This is the container executor setting that ensures that all
+jobs are started with the DockerContainerExecutor.
+
+
+----
+
+ 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: /. 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: /.
+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
+----
+
+ 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=
+ to this JVM property.
+
+ * mapreduce.reduce.env: You can override the reducer's image by passing
+ yarn.nodemanager.docker-container-executor.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=
+ 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).
+
+----
+
+ yarn.nodemanager.docker-container-executor.exec-name
+ docker -H=tcp://0.0.0.0:4243
+
+ Name or path to the Docker client. The tcp socket must be
+ where docker daemon is listening.
+
+
+
+
+ yarn.nodemanager.container-executor.class
+ org.apache.hadoop.yarn.server.nodemanager.DockerContainerExecutor
+
+ This is the container executor setting that ensures that all
+jobs are started with the DockerContainerExecutor.
+
+
+----
+
+ * 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.
+