Java tutorial
/** * 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.mapred; import java.io.File; import java.io.IOException; import java.net.InetSocketAddress; import java.util.ArrayList; import java.util.Arrays; import java.util.List; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.fs.FSDataOutputStream; import org.apache.hadoop.fs.FileSystem; import org.apache.hadoop.fs.LocalDirAllocator; import org.apache.hadoop.fs.LocalFileSystem; import org.apache.hadoop.fs.Path; import org.apache.hadoop.fs.permission.FsPermission; import org.apache.hadoop.mapred.TaskTracker.LocalStorage; import org.apache.hadoop.util.ProcessTree.Signal; import org.apache.hadoop.util.Shell.ExitCodeException; import org.apache.hadoop.util.Shell.ShellCommandExecutor; import org.apache.hadoop.util.StringUtils; /** * A {@link TaskController} that runs the task JVMs as the user * who submits the job. * * This class executes a setuid executable to implement methods * of the {@link TaskController}, including launching the task * JVM and killing it when needed, and also initializing and * finalizing the task environment. * <p> The setuid executable is launched using the command line:</p> * <p>task-controller user-name good-local-dirs command command-args, * where</p> * <p>user-name is the name of the owner who submits the job</p> * <p>good-local-dirs is comma separated list of good mapred local dirs</p> * <p>command is one of the cardinal value of the * {@link LinuxTaskController.TaskControllerCommands} enumeration</p> * <p>command-args depends on the command being launched.</p> * * In addition to running and killing tasks, the class also * sets up appropriate access for the directories and files * that will be used by the tasks. */ class LinuxTaskController extends TaskController { private static final Log LOG = LogFactory.getLog(LinuxTaskController.class); // Path to the setuid executable. private String taskControllerExe; private static final String TASK_CONTROLLER_EXEC_KEY = "mapreduce.tasktracker.task-controller.exe"; @Override public void setConf(Configuration conf) { super.setConf(conf); File hadoopBin = new File(System.getenv("HADOOP_HOME"), "bin"); String defaultTaskController = new File(hadoopBin, "task-controller").getAbsolutePath(); taskControllerExe = conf.get(TASK_CONTROLLER_EXEC_KEY, defaultTaskController); } public LinuxTaskController() { super(); } /** * List of commands that the setuid script will execute. */ enum Commands { INITIALIZE_JOB(0), LAUNCH_TASK_JVM(1), SIGNAL_TASK(2), DELETE_AS_USER(3), DELETE_LOG_AS_USER( 4), RUN_COMMAND_AS_USER(5); private int value; Commands(int value) { this.value = value; } int getValue() { return value; } } /** * Result codes returned from the C task-controller. * These must match the values in task-controller.h. */ enum ResultCode { OK(0), INVALID_USER_NAME(2), INVALID_TASK_PID(9), INVALID_CONFIG_FILE(24); private final int value; ResultCode(int value) { this.value = value; } int getValue() { return value; } } @Override public void setup(LocalDirAllocator allocator, LocalStorage localStorage) throws IOException { // Check the permissions of the task-controller binary by running it plainly. // If permissions are correct, it returns an error code 1, else it returns // 24 or something else if some other bugs are also present. String[] taskControllerCmd = new String[] { taskControllerExe }; ShellCommandExecutor shExec = new ShellCommandExecutor(taskControllerCmd); try { shExec.execute(); } catch (ExitCodeException e) { int exitCode = shExec.getExitCode(); if (exitCode != 1) { LOG.warn("Exit code from checking binary permissions is : " + exitCode); logOutput(shExec.getOutput()); throw new IOException("Task controller setup failed because of invalid" + "permissions/ownership with exit code " + exitCode, e); } } this.allocator = allocator; this.localStorage = localStorage; } @Override public void initializeJob(String user, String jobid, Path credentials, Path jobConf, TaskUmbilicalProtocol taskTracker, InetSocketAddress ttAddr) throws IOException { List<String> command = new ArrayList<String>(Arrays.asList(taskControllerExe, user, localStorage.getDirsString(), Integer.toString(Commands.INITIALIZE_JOB.getValue()), jobid, credentials.toUri().getPath().toString(), jobConf.toUri().getPath().toString())); File jvm = // use same jvm as parent new File(new File(System.getProperty("java.home"), "bin"), "java"); command.add(jvm.toString()); command.add("-classpath"); command.add(System.getProperty("java.class.path")); command.add("-Dhadoop.log.dir=" + TaskLog.getBaseLogDir()); command.add("-Dhadoop.root.logger=INFO,console"); command.add("-Djava.library.path=" + System.getProperty("java.library.path")); command.add(JobLocalizer.class.getName()); // main of JobLocalizer command.add(user); command.add(jobid); // add the task tracker's reporting address command.add(ttAddr.getHostName()); command.add(Integer.toString(ttAddr.getPort())); String[] commandArray = command.toArray(new String[0]); ShellCommandExecutor shExec = new ShellCommandExecutor(commandArray); if (LOG.isDebugEnabled()) { LOG.debug("initializeJob: " + Arrays.toString(commandArray)); } try { shExec.execute(); if (LOG.isDebugEnabled()) { logOutput(shExec.getOutput()); } } catch (ExitCodeException e) { int exitCode = shExec.getExitCode(); logOutput(shExec.getOutput()); throw new IOException("Job initialization failed (" + exitCode + ") with output: " + shExec.getOutput(), e); } } @Override public int launchTask(String user, String jobId, String attemptId, List<String> setup, List<String> jvmArguments, File currentWorkDirectory, String stdout, String stderr) throws IOException { ShellCommandExecutor shExec = null; try { FileSystem rawFs = FileSystem.getLocal(getConf()).getRaw(); long logSize = 0; //TODO MAPREDUCE-1100 // get the JVM command line. String cmdLine = TaskLog.buildCommandLine(setup, jvmArguments, new File(stdout), new File(stderr), logSize, true); // write the command to a file in the // task specific cache directory Path p = new Path( allocator.getLocalPathForWrite( TaskTracker.getPrivateDirTaskScriptLocation(user, jobId, attemptId), getConf()), COMMAND_FILE); String commandFile = writeCommand(cmdLine, rawFs, p); String[] command = new String[] { taskControllerExe, user, localStorage.getDirsString(), Integer.toString(Commands.LAUNCH_TASK_JVM.getValue()), jobId, attemptId, currentWorkDirectory.toString(), commandFile }; shExec = new ShellCommandExecutor(command); if (LOG.isDebugEnabled()) { LOG.debug("launchTask: " + Arrays.toString(command)); } shExec.execute(); } catch (Exception e) { if (shExec == null) { return -1; } int exitCode = shExec.getExitCode(); LOG.warn("Exit code from task is : " + exitCode); // 143 (SIGTERM) and 137 (SIGKILL) exit codes means the task was // terminated/killed forcefully. In all other cases, log the // task-controller output if (exitCode != 143 && exitCode != 137) { LOG.warn("Exception thrown while launching task JVM : " + StringUtils.stringifyException(e)); LOG.info("Output from LinuxTaskController's launchTaskJVM follows:"); logOutput(shExec.getOutput()); } return exitCode; } if (LOG.isDebugEnabled()) { LOG.debug("Output from LinuxTaskController's launchTask follows:"); logOutput(shExec.getOutput()); } return 0; } @Override public void deleteAsUser(String user, String subDir) throws IOException { String[] command = new String[] { taskControllerExe, user, localStorage.getDirsString(), Integer.toString(Commands.DELETE_AS_USER.getValue()), subDir }; ShellCommandExecutor shExec = new ShellCommandExecutor(command); if (LOG.isDebugEnabled()) { LOG.debug("deleteAsUser: " + Arrays.toString(command)); } shExec.execute(); } @Override public void deleteLogAsUser(String user, String subDir) throws IOException { String[] command = new String[] { taskControllerExe, user, localStorage.getDirsString(), Integer.toString(Commands.DELETE_LOG_AS_USER.getValue()), subDir }; ShellCommandExecutor shExec = new ShellCommandExecutor(command); if (LOG.isDebugEnabled()) { LOG.debug("deleteLogAsUser: " + Arrays.toString(command)); } shExec.execute(); } @Override public void signalTask(String user, int taskPid, Signal signal) throws IOException { String[] command = new String[] { taskControllerExe, user, localStorage.getDirsString(), Integer.toString(Commands.SIGNAL_TASK.getValue()), Integer.toString(taskPid), Integer.toString(signal.getValue()) }; ShellCommandExecutor shExec = new ShellCommandExecutor(command); if (LOG.isDebugEnabled()) { LOG.debug("signalTask: " + Arrays.toString(command)); } try { shExec.execute(); } catch (ExitCodeException e) { int ret_code = shExec.getExitCode(); if (ret_code != ResultCode.INVALID_TASK_PID.getValue()) { logOutput(shExec.getOutput()); throw new IOException( "Problem signalling task " + taskPid + " with " + signal + "; exit = " + ret_code); } } } @Override public String getRunAsUser(JobConf conf) { return conf.getUser(); } @Override public void truncateLogsAsUser(String user, List<Task> allAttempts) throws IOException { Task firstTask = allAttempts.get(0); String taskid = firstTask.getTaskID().toString(); LocalDirAllocator ldirAlloc = new LocalDirAllocator(JobConf.MAPRED_LOCAL_DIR_PROPERTY); String taskRanFile = TaskTracker.TT_LOG_TMP_DIR + Path.SEPARATOR + taskid; Configuration conf = getConf(); //write the serialized task information to a file to pass to the truncater Path taskRanFilePath = ldirAlloc.getLocalPathForWrite(taskRanFile, conf); LocalFileSystem lfs = FileSystem.getLocal(conf); FSDataOutputStream out = lfs.create(taskRanFilePath); out.writeInt(allAttempts.size()); for (Task t : allAttempts) { out.writeBoolean(t.isMapTask()); t.write(out); } out.close(); lfs.setPermission(taskRanFilePath, FsPermission.createImmutable((short) 0755)); List<String> command = new ArrayList<String>(); File jvm = // use same jvm as parent new File(new File(System.getProperty("java.home"), "bin"), "java"); command.add(jvm.toString()); command.add("-Djava.library.path=" + System.getProperty("java.library.path")); command.add("-Dhadoop.log.dir=" + TaskLog.getBaseLogDir()); command.add("-Dhadoop.root.logger=INFO,console"); command.add("-classpath"); command.add(System.getProperty("java.class.path")); // main of TaskLogsTruncater command.add(TaskLogsTruncater.class.getName()); command.add(taskRanFilePath.toString()); String[] taskControllerCmd = new String[4 + command.size()]; taskControllerCmd[0] = taskControllerExe; taskControllerCmd[1] = user; taskControllerCmd[2] = localStorage.getDirsString(); taskControllerCmd[3] = Integer.toString(Commands.RUN_COMMAND_AS_USER.getValue()); int i = 4; for (String cmdArg : command) { taskControllerCmd[i++] = cmdArg; } if (LOG.isDebugEnabled()) { for (String cmd : taskControllerCmd) { LOG.debug("taskctrl command = " + cmd); } } ShellCommandExecutor shExec = new ShellCommandExecutor(taskControllerCmd); try { shExec.execute(); } catch (Exception e) { LOG.warn("Exit code from " + taskControllerExe.toString() + " is : " + shExec.getExitCode() + " for truncateLogs"); LOG.warn("Exception thrown by " + taskControllerExe.toString() + " : " + StringUtils.stringifyException(e)); LOG.info("Output from LinuxTaskController's " + taskControllerExe.toString() + " follows:"); logOutput(shExec.getOutput()); lfs.delete(taskRanFilePath, false); throw new IOException(e); } lfs.delete(taskRanFilePath, false); if (LOG.isDebugEnabled()) { LOG.info("Output from LinuxTaskController's " + taskControllerExe.toString() + " follows:"); logOutput(shExec.getOutput()); } } }