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.twill.yarn; import com.google.common.base.Throwables; import com.google.common.collect.ImmutableList; import com.google.common.util.concurrent.ListenableFuture; import com.google.common.util.concurrent.Uninterruptibles; import org.apache.commons.lang.time.StopWatch; import org.apache.hadoop.yarn.api.records.ApplicationId; import org.apache.hadoop.yarn.api.records.FinalApplicationStatus; import org.apache.hadoop.yarn.api.records.YarnApplicationState; import org.apache.twill.api.ResourceReport; import org.apache.twill.api.RunId; import org.apache.twill.api.TwillController; import org.apache.twill.api.logging.LogHandler; import org.apache.twill.internal.AbstractTwillController; import org.apache.twill.internal.Constants; import org.apache.twill.internal.ProcessController; import org.apache.twill.internal.appmaster.TrackerService; import org.apache.twill.internal.state.SystemMessages; import org.apache.twill.internal.yarn.YarnApplicationReport; import org.apache.twill.zookeeper.NodeData; import org.apache.twill.zookeeper.ZKClient; import org.apache.zookeeper.data.Stat; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import java.io.IOException; import java.net.URI; import java.net.URL; import java.util.concurrent.Callable; import java.util.concurrent.ExecutionException; import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeoutException; /** * A {@link org.apache.twill.api.TwillController} that controllers application running on Hadoop YARN. */ final class YarnTwillController extends AbstractTwillController implements TwillController { private static final Logger LOG = LoggerFactory.getLogger(YarnTwillController.class); private final String appName; private final Callable<ProcessController<YarnApplicationReport>> startUp; private ProcessController<YarnApplicationReport> processController; private ResourceReportClient resourcesClient; // Thread for polling yarn for application status if application got ZK session expire. // Only used by the instanceUpdate/Delete method, which is from serialized call from ZK callback. private Thread statusPollingThread; /** * Creates an instance without any {@link LogHandler}. */ YarnTwillController(String appName, RunId runId, ZKClient zkClient, Callable<ProcessController<YarnApplicationReport>> startUp) { this(appName, runId, zkClient, ImmutableList.<LogHandler>of(), startUp); } YarnTwillController(String appName, RunId runId, ZKClient zkClient, Iterable<LogHandler> logHandlers, Callable<ProcessController<YarnApplicationReport>> startUp) { super(runId, zkClient, logHandlers); this.appName = appName; this.startUp = startUp; } /** * Sends a message to application to notify the secure store has be updated. */ ListenableFuture<Void> secureStoreUpdated() { return sendMessage(SystemMessages.SECURE_STORE_UPDATED, null); } @Override protected void doStartUp() { super.doStartUp(); // Submit and poll the status of the yarn application try { processController = startUp.call(); YarnApplicationReport report = processController.getReport(); ApplicationId appId = report.getApplicationId(); LOG.debug("Application {} with id {} submitted", appName, appId); YarnApplicationState state = report.getYarnApplicationState(); StopWatch stopWatch = new StopWatch(); stopWatch.start(); stopWatch.split(); long maxTime = TimeUnit.MILLISECONDS.convert(Constants.APPLICATION_MAX_START_SECONDS, TimeUnit.SECONDS); LOG.debug("Checking yarn application status for {} {}", appName, appId); while (!hasRun(state) && stopWatch.getSplitTime() < maxTime) { report = processController.getReport(); state = report.getYarnApplicationState(); LOG.debug("Yarn application status for {} {}: {}", appName, appId, state); TimeUnit.SECONDS.sleep(1); stopWatch.split(); } LOG.info("Yarn application {} {} is in state {}", appName, appId, state); if (state != YarnApplicationState.RUNNING) { LOG.info("Yarn application {} {} is not in running state. Shutting down controller.", appName, appId, Constants.APPLICATION_MAX_START_SECONDS); forceShutDown(); } else { try { URL resourceUrl = URI .create(String.format("http://%s:%d", report.getHost(), report.getRpcPort())) .resolve(TrackerService.PATH).toURL(); resourcesClient = new ResourceReportClient(resourceUrl); } catch (IOException e) { resourcesClient = null; } } } catch (Exception e) { throw Throwables.propagate(e); } } @Override protected synchronized void doShutDown() { if (processController == null) { LOG.warn("No process controller for application that is not submitted."); return; } // Stop polling if it is running. stopPollStatus(); // Wait for the stop message being processed try { Uninterruptibles.getUninterruptibly(getStopMessageFuture(), Constants.APPLICATION_MAX_STOP_SECONDS, TimeUnit.SECONDS); } catch (Exception e) { LOG.error("Failed to wait for stop message being processed.", e); // Kill the application through yarn kill(); } // Poll application status from yarn try { StopWatch stopWatch = new StopWatch(); stopWatch.start(); stopWatch.split(); long maxTime = TimeUnit.MILLISECONDS.convert(Constants.APPLICATION_MAX_STOP_SECONDS, TimeUnit.SECONDS); YarnApplicationReport report = processController.getReport(); FinalApplicationStatus finalStatus = report.getFinalApplicationStatus(); ApplicationId appId = report.getApplicationId(); while (finalStatus == FinalApplicationStatus.UNDEFINED && stopWatch.getSplitTime() < maxTime) { LOG.debug("Yarn application final status for {} {}: {}", appName, appId, finalStatus); TimeUnit.SECONDS.sleep(1); stopWatch.split(); finalStatus = processController.getReport().getFinalApplicationStatus(); } LOG.debug("Yarn application {} {} completed with status {}", appName, appId, finalStatus); // Application not finished after max stop time, kill the application if (finalStatus == FinalApplicationStatus.UNDEFINED) { kill(); } } catch (Exception e) { LOG.warn("Exception while waiting for application report: {}", e.getMessage(), e); kill(); } super.doShutDown(); } @Override public void kill() { if (processController != null) { YarnApplicationReport report = processController.getReport(); LOG.info("Killing application {} {}", appName, report.getApplicationId()); processController.cancel(); } else { LOG.warn("No process controller for application that is not submitted."); } } @Override protected void instanceNodeUpdated(NodeData nodeData) { } @Override protected void instanceNodeFailed(Throwable cause) { // Resort to polling from Yarn for the application status. if (processController == null) { LOG.warn("No process controller for application that is not submitted."); return; } YarnApplicationReport report = processController.getReport(); // It happens if the application has ZK session expire or the node is deleted due to application termination. LOG.info("Failed to access application {} {} live node in ZK, resort to polling. Failure reason: {}", appName, report.getApplicationId(), cause == null ? "Unknown" : cause.getMessage()); startPollStatus(report.getApplicationId()); } private synchronized void startPollStatus(ApplicationId appId) { if (statusPollingThread == null) { statusPollingThread = new Thread(createStatusPollingRunnable(), String.format("%s-%s-yarn-poller", appName, appId)); statusPollingThread.setDaemon(true); statusPollingThread.start(); } } private synchronized void stopPollStatus() { if (statusPollingThread != null) { statusPollingThread.interrupt(); statusPollingThread = null; } } private Runnable createStatusPollingRunnable() { return new Runnable() { @Override public void run() { YarnApplicationReport report = processController.getReport(); ApplicationId appId = report.getApplicationId(); boolean shutdown = false; boolean watchInstanceNode = false; try { LOG.debug("Polling status from Yarn for {} {}.", appName, appId); while (!Thread.currentThread().isInterrupted()) { if (report.getFinalApplicationStatus() != FinalApplicationStatus.UNDEFINED) { shutdown = true; break; } // Make a sync exists call to instance node and re-watch if the node exists try { // The timeout is arbitrary, as it's just for avoiding block forever Stat stat = zkClient.exists(getInstancePath()).get(5, TimeUnit.SECONDS); if (stat != null) { watchInstanceNode = true; break; } } catch (ExecutionException e) { // Ignore the exception, as any exception won't affect the status polling. LOG.debug("Failed in exists call on ZK path {}.", getInstancePath(), e); } catch (TimeoutException e) { LOG.debug("Timeout in exists call on ZK path {}.", getInstancePath(), e); } TimeUnit.SECONDS.sleep(1); report = processController.getReport(); } } catch (InterruptedException e) { // OK to ignore. LOG.debug("Status polling thread interrupted for application {} {}", appName, appId); } LOG.debug("Stop polling status from Yarn for {} {}.", appName, appId); if (shutdown) { LOG.info("Yarn application {} {} completed. Shutting down controller.", appName, appId); forceShutDown(); } else if (watchInstanceNode) { LOG.info("Rewatch instance node for {} {} at {}", appName, appId, getInstancePath()); synchronized (YarnTwillController.this) { statusPollingThread = null; watchInstanceNode(); } } } }; } private boolean hasRun(YarnApplicationState state) { switch (state) { case RUNNING: case FINISHED: case FAILED: case KILLED: return true; } return false; } @Override public ResourceReport getResourceReport() { // in case the user calls this before starting, return null return (resourcesClient == null) ? null : resourcesClient.get(); } }