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 com.flyhz.avengers.framework.application; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.nio.ByteBuffer; import java.util.ArrayList; import java.util.HashMap; import java.util.Iterator; import java.util.List; import java.util.Map; import java.util.Map.Entry; import java.util.Vector; import java.util.concurrent.ConcurrentHashMap; import java.util.concurrent.ConcurrentMap; import java.util.concurrent.atomic.AtomicInteger; import org.apache.commons.cli.CommandLine; import org.apache.commons.cli.GnuParser; import org.apache.commons.cli.Options; import org.apache.commons.cli.ParseException; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.classification.InterfaceStability; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hbase.HBaseConfiguration; import org.apache.hadoop.hbase.client.HBaseAdmin; import org.apache.hadoop.hbase.client.HConnection; import org.apache.hadoop.hbase.client.HConnectionManager; import org.apache.hadoop.hbase.client.HTable; import org.apache.hadoop.hbase.client.Result; import org.apache.hadoop.hbase.client.ResultScanner; import org.apache.hadoop.hbase.client.Scan; import org.apache.hadoop.hbase.util.Bytes; import org.apache.hadoop.io.DataOutputBuffer; import org.apache.hadoop.net.NetUtils; import org.apache.hadoop.security.Credentials; import org.apache.hadoop.security.UserGroupInformation; import org.apache.hadoop.security.token.Token; import org.apache.hadoop.yarn.api.ApplicationConstants; import org.apache.hadoop.yarn.api.ApplicationConstants.Environment; import org.apache.hadoop.yarn.api.ContainerManagementProtocol; import org.apache.hadoop.yarn.api.protocolrecords.RegisterApplicationMasterResponse; import org.apache.hadoop.yarn.api.records.ApplicationAttemptId; import org.apache.hadoop.yarn.api.records.Container; import org.apache.hadoop.yarn.api.records.ContainerExitStatus; import org.apache.hadoop.yarn.api.records.ContainerId; import org.apache.hadoop.yarn.api.records.ContainerLaunchContext; import org.apache.hadoop.yarn.api.records.ContainerState; import org.apache.hadoop.yarn.api.records.ContainerStatus; import org.apache.hadoop.yarn.api.records.FinalApplicationStatus; import org.apache.hadoop.yarn.api.records.LocalResource; import org.apache.hadoop.yarn.api.records.NodeReport; import org.apache.hadoop.yarn.api.records.Priority; import org.apache.hadoop.yarn.api.records.Resource; import org.apache.hadoop.yarn.client.api.AMRMClient.ContainerRequest; import org.apache.hadoop.yarn.client.api.async.AMRMClientAsync; import org.apache.hadoop.yarn.client.api.async.NMClientAsync; import org.apache.hadoop.yarn.client.api.async.impl.NMClientAsyncImpl; import org.apache.hadoop.yarn.conf.YarnConfiguration; import org.apache.hadoop.yarn.exceptions.YarnException; import org.apache.hadoop.yarn.security.AMRMTokenIdentifier; import org.apache.hadoop.yarn.util.ConverterUtils; import org.apache.hadoop.yarn.util.Records; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import com.flyhz.avengers.framework.Fetch; import com.flyhz.avengers.framework.common.dto.XPairDto; import com.flyhz.avengers.framework.config.XConfiguration; import com.flyhz.avengers.framework.lang.AVTable; import com.flyhz.avengers.framework.lang.AVTable.AVColumn; import com.flyhz.avengers.framework.lang.AVTable.AVFamily; import com.google.common.annotations.VisibleForTesting; @InterfaceAudience.Public @InterfaceStability.Unstable public class FetchApplication { private static final Logger LOG = LoggerFactory.getLogger(FetchApplication.class); // XConfiguration private Configuration conf; // hbase private final Configuration hbaseConf = HBaseConfiguration.create(); // Handle to communicate with the Resource Manager // @SuppressWarnings("rawtypes") private AMRMClientAsync<ContainerRequest> amRMClient; // Handle to communicate with the Node Manager private NMClientAsync nmClientAsync; // Listen to process the response from the Node Manager private NMCallbackHandler containerListener; // Application Attempt Key ( combination of attemptId and fail count ) private ApplicationAttemptId appAttemptID; // For status update for clients - yet to be implemented // Hostname of the container private String appMasterHostname = ""; // Port on which the app master listens for status updates from clients private int appMasterRpcPort = -1; // Tracking url to which app master publishes info for clients to monitor private String appMasterTrackingUrl = ""; // App Master configuration // No. of containers to run shell command on private int numTotalContainers = 1; // Memory to request for the container on which the shell command will run private int containerMemory = 10; // Priority of the request private int requestPriority; // Counter for completed containers ( complete denotes successful or failed // ) private AtomicInteger numCompletedContainers = new AtomicInteger(); // Allocated container count so that we know how many containers has the RM // allocated to us private AtomicInteger numAllocatedContainers = new AtomicInteger(); // Count of failed containers private AtomicInteger numFailedContainers = new AtomicInteger(); // Count of containers already requested from the RM // Needed as once requested, we should not request for containers again. // Only request for more if the original requirement changes. private AtomicInteger numRequestedContainers = new AtomicInteger(); private volatile boolean done; private volatile boolean success; private ByteBuffer allTokens; // Launch threads private List<Thread> launchThreads = new ArrayList<Thread>(); private long batchId; private Options opts; private Vector<XPairDto<Long, Long>> pairs = new Vector<XPairDto<Long, Long>>(); public FetchApplication() { // Set up the configuration conf = new YarnConfiguration(); hbaseConf.set("hbase.zookeeper.quorum", "m1,s1,s2"); hbaseConf.set("hbase.zookeeper.property.clientPort", "2181"); } /** * @param args * Command line args */ public static void main(String[] args) { boolean result = false; try { FetchApplication fetchApplication = new FetchApplication(); LOG.info("Initializing AvengersAppMaster"); boolean doRun = fetchApplication.init(args); if (!doRun) { System.exit(0); } result = fetchApplication.run(); } catch (Throwable t) { LOG.error("Error running AvengersAppMaster", t); System.exit(1); } if (result) { LOG.info("Application Master completed successfully. exiting"); System.exit(0); } else { LOG.info("Application Master failed. exiting"); System.exit(2); } } /** * Dump out contents of $CWD and the environment to stdout for debugging */ @SuppressWarnings("unused") private void dumpOutDebugInfo() { LOG.info("Dump debug output"); Map<String, String> envs = System.getenv(); for (Map.Entry<String, String> env : envs.entrySet()) { LOG.info("System env: key=" + env.getKey() + ", val=" + env.getValue()); System.out.println("System env: key=" + env.getKey() + ", val=" + env.getValue()); } String cmd = "ls -al"; Runtime run = Runtime.getRuntime(); Process pr = null; try { pr = run.exec(cmd); pr.waitFor(); BufferedReader buf = new BufferedReader(new InputStreamReader(pr.getInputStream())); String line = ""; while ((line = buf.readLine()) != null) { LOG.info("System CWD content: " + line); System.out.println("System CWD content: " + line); } buf.close(); } catch (IOException e) { e.printStackTrace(); } catch (InterruptedException e) { e.printStackTrace(); } } /** * URLCrawlEvent command line options * * @param args * Command line args * @return Whether init successful and run should be invoked * @throws ParseException * @throws IOException */ public boolean init(String[] args) throws ParseException, IOException { LOG.info("init ...... first"); if (args.length == 0) { throw new IllegalArgumentException("No args specified for client to initialize"); } opts = new Options(); opts.addOption("batchId", true, "batchId"); CommandLine cliParser = new GnuParser().parse(opts, args); this.batchId = Long.valueOf(cliParser.getOptionValue("batchId")); Map<String, String> envs = System.getenv(); if (!envs.containsKey(Environment.CONTAINER_ID.name())) { throw new IllegalArgumentException("Application Attempt Key not set in the environment"); } else { ContainerId containerId = ConverterUtils.toContainerId(envs.get(Environment.CONTAINER_ID.name())); appAttemptID = containerId.getApplicationAttemptId(); } if (!envs.containsKey(ApplicationConstants.APP_SUBMIT_TIME_ENV)) { throw new RuntimeException(ApplicationConstants.APP_SUBMIT_TIME_ENV + " not set in the environment"); } if (!envs.containsKey(Environment.NM_HOST.name())) { throw new RuntimeException(Environment.NM_HOST.name() + " not set in the environment"); } if (!envs.containsKey(Environment.NM_HTTP_PORT.name())) { throw new RuntimeException(Environment.NM_HTTP_PORT + " not set in the environment"); } if (!envs.containsKey(Environment.NM_PORT.name())) { throw new RuntimeException(Environment.NM_PORT.name() + " not set in the environment"); } LOG.info("Application master for app" + ", appId=" + appAttemptID.getApplicationId().getId() + ", clustertimestamp=" + appAttemptID.getApplicationId().getClusterTimestamp() + ", attemptId=" + appAttemptID.getAttemptId()); containerMemory = 10; if (numTotalContainers == 0) { throw new IllegalArgumentException("Cannot run distributed shell with no containers"); } requestPriority = 0; return true; } /** * Main run function for the application master * * @throws YarnException * @throws IOException */ public boolean run() throws IOException, YarnException { LOG.info("Starting AvengersAppMaster"); Credentials credentials = UserGroupInformation.getCurrentUser().getCredentials(); DataOutputBuffer dob = new DataOutputBuffer(); credentials.writeTokenStorageToStream(dob); // Now remove the AM->RM token so that containers cannot access it. Iterator<Token<?>> iter = credentials.getAllTokens().iterator(); while (iter.hasNext()) { Token<?> token = iter.next(); if (token.getKind().equals(AMRMTokenIdentifier.KIND_NAME)) { iter.remove(); } } allTokens = ByteBuffer.wrap(dob.getData(), 0, dob.getLength()); AMRMClientAsync.CallbackHandler allocListener = new RMCallbackHandler(); amRMClient = AMRMClientAsync.createAMRMClientAsync(1000, allocListener); amRMClient.init(conf); amRMClient.start(); containerListener = createNMCallbackHandler(); nmClientAsync = new NMClientAsyncImpl(containerListener); nmClientAsync.init(conf); nmClientAsync.start(); // Setup local RPC Server to accept status requests directly from // clients // the RPC server // send requests to this app master // Register self with ResourceManager // This will first hearInitializing Clienttbeating to the RM appMasterHostname = NetUtils.getHostname(); RegisterApplicationMasterResponse response = amRMClient.registerApplicationMaster(appMasterHostname, appMasterRpcPort, appMasterTrackingUrl); // Dump out information about cluster capability as seen by the // resource manager int maxMem = response.getMaximumResourceCapability().getMemory(); LOG.info("Max mem capabililty of resources in this cluster " + maxMem); // A resource ask cannot exceed the max. if (containerMemory > maxMem) { LOG.info("Container memory specified above max threshold of cluster." + " Using max value." + ", specified=" + containerMemory + ", max=" + maxMem); containerMemory = maxMem; } fetch(); finish(); return success; } @VisibleForTesting NMCallbackHandler createNMCallbackHandler() { return new NMCallbackHandler(this); } private void fetch() { LOG.info("initFetch first ......"); HConnection hConnection = null; HBaseAdmin hbaseAdmin = null; // HTable hVersion = null; HTable hPage = null; HTable hDomain = null; try { hConnection = HConnectionManager.createConnection(hbaseConf); hbaseAdmin = new HBaseAdmin(hConnection); Configuration configuration = HBaseConfiguration.create(hbaseConf); configuration.setLong("hbase.rpc.timeout", 1200000); // Scan configuration.setLong("hbase.client.scanner.caching", 1000); hPage = new HTable(hbaseConf, AVTable.av_page.name()); Scan hPageScan = new Scan(); hPageScan.addColumn(Bytes.toBytes(AVFamily.i.name()), Bytes.toBytes(AVColumn.bid.name())); ResultScanner hPageRs = hPage.getScanner(hPageScan); if (hPageRs != null) { Long startKey = 0L; Long endKey = 0L; for (Result result : hPageRs) { Long id = Bytes.toLong(result.getRow()); Long batchId = Bytes.toLong( result.getValue(Bytes.toBytes(AVFamily.i.name()), Bytes.toBytes(AVColumn.bid.name()))); if (this.batchId == batchId) { LOG.info("rowkey -> {},batchId ->{}", id, batchId); startKey = id; break; } } hDomain = new HTable(hbaseConf, AVTable.av_domain.name()); Scan hDomainScan = new Scan(); hDomainScan.addColumn(Bytes.toBytes(AVFamily.i.name()), Bytes.toBytes(AVColumn.maxid.name())); ResultScanner hDomainRs = hDomain.getScanner(hDomainScan); if (hDomainRs == null) { return; } for (Result result : hDomainRs) { Long value = Bytes.toLong(result.getValue(Bytes.toBytes(AVFamily.i.name()), Bytes.toBytes(AVColumn.maxid.name()))); if (endKey.compareTo(value) < 0) { endKey = value; } } endKey = endKey + 1; LOG.info("startKey > {},endKey > {}", startKey, endKey); numTotalContainers = (Integer) XConfiguration.getAvengersContext() .get(XConfiguration.NUM_FETCH_CONTAINERS); Long size = (endKey - startKey + 1) / numTotalContainers; for (int i = 0; i < numTotalContainers; i++) { Long sk = startKey + size * i; Long ek = startKey + size * (i + 1); LOG.info("start > {} end > {}", sk, ek); XPairDto<Long, Long> pair = new XPairDto<Long, Long>(sk, ek); pairs.add(pair); ContainerRequest containerAsk = setupContainerAskForRM(); amRMClient.addContainerRequest(containerAsk); } for (int i = 0; i < numTotalContainers; i++) { // ContainerRequest containerAsk = setupContainerAskForRM(); // amRMClient.addContainerRequest(containerAsk); } numRequestedContainers.set(numTotalContainers); while (!done && (numCompletedContainers.get() != numTotalContainers)) { try { Thread.sleep(200); } catch (InterruptedException ex) { } } } } catch (IOException e) { LOG.error("fetch", e); } catch (Throwable e) { LOG.error("fetch", e); } finally { if (hPage != null) { try { hPage.close(); } catch (IOException e) { LOG.error("", e); } } if (hbaseAdmin != null) { try { hbaseAdmin.close(); } catch (IOException e) { LOG.error("", e); } } if (hConnection != null) { try { hConnection.close(); } catch (IOException e) { LOG.error("", e); } } } } private void finish() { // Join all launched threads // needed for when we time out // and we need to release containers for (Thread launchThread : launchThreads) { try { launchThread.join(10000); } catch (InterruptedException e) { LOG.info("Exception thrown in thread join: " + e.getMessage()); e.printStackTrace(); } } // When the application completes, it should stop all running containers LOG.info("Application completed. Stopping running containers"); nmClientAsync.stop(); // When the application completes, it should send a finish application // signal to the RM LOG.info("Application completed. Signalling finish to RM"); FinalApplicationStatus appStatus; String appMessage = null; success = true; if (numFailedContainers.get() == 0 && numCompletedContainers.get() == numTotalContainers) { appStatus = FinalApplicationStatus.SUCCEEDED; } else { appStatus = FinalApplicationStatus.FAILED; appMessage = "Diagnostics." + ", total=" + numTotalContainers + ", completed=" + numCompletedContainers.get() + ", allocated=" + numAllocatedContainers.get() + ", failed=" + numFailedContainers.get(); success = false; } try { amRMClient.unregisterApplicationMaster(appStatus, appMessage, null); } catch (YarnException ex) { LOG.error("Failed to unregister application", ex); } catch (IOException e) { LOG.error("Failed to unregister application", e); } amRMClient.stop(); } private class RMCallbackHandler implements AMRMClientAsync.CallbackHandler { @Override public void onContainersCompleted(List<ContainerStatus> completedContainers) { LOG.info("Got response from RM for container ask, completedCnt=" + completedContainers.size()); for (ContainerStatus containerStatus : completedContainers) { LOG.info("Got container status for containerID=" + containerStatus.getContainerId() + ", state=" + containerStatus.getState() + ", exitStatus=" + containerStatus.getExitStatus() + ", diagnostics=" + containerStatus.getDiagnostics()); // non complete containers should not be here assert (containerStatus.getState() == ContainerState.COMPLETE); // increment counters for completed/failed containers int exitStatus = containerStatus.getExitStatus(); if (0 != exitStatus) { // container failed if (ContainerExitStatus.ABORTED != exitStatus) { // shell script failed // counts as completed numCompletedContainers.incrementAndGet(); numFailedContainers.incrementAndGet(); } else { // container was killed by framework, possibly preempted // we should re-try as the container was lost for some // reason numAllocatedContainers.decrementAndGet(); numRequestedContainers.decrementAndGet(); // we do not need to release the container as it would // be done // by the RM } } else { // nothing to do // container completed successfully numCompletedContainers.incrementAndGet(); LOG.info("Container completed successfully." + ", containerId=" + containerStatus.getContainerId()); } } // ask for more containers if any failed int askCount = numTotalContainers - numRequestedContainers.get(); numRequestedContainers.addAndGet(askCount); if (askCount > 0) { for (int i = 0; i < askCount; ++i) { ContainerRequest containerAsk = setupContainerAskForRM(); amRMClient.addContainerRequest(containerAsk); } } if (numCompletedContainers.get() == numTotalContainers) { done = true; } } @Override public void onContainersAllocated(List<Container> allocatedContainers) { LOG.info("Got response from RM for container ask, allocatedCnt={}", allocatedContainers.size()); numAllocatedContainers.addAndGet(allocatedContainers.size()); for (int i = 0; i < allocatedContainers.size(); i++) { Container allocatedContainer = allocatedContainers.get(i); Iterator<XPairDto<Long, Long>> it = pairs.iterator(); if (it.hasNext()) { LOG.info("Launching shell command on a new container." + ", containerId=" + allocatedContainer.getId() + ", containerNode=" + allocatedContainer.getNodeId().getHost() + ":" + allocatedContainer.getNodeId().getPort() + ", containerNodeURI=" + allocatedContainer.getNodeHttpAddress() + ", containerResourceMemory" + allocatedContainer.getResource().getMemory()); LaunchContainerRunnable runnableLaunchContainer = new LaunchContainerRunnable( allocatedContainer, containerListener, it.next(), batchId); Thread launchThread = new Thread(runnableLaunchContainer); launchThreads.add(launchThread); launchThread.start(); it.remove(); } // launch and first the container on a separate thread to keep // the main thread unblocked // as all containers may not be allocated at one go. } } @Override public void onShutdownRequest() { done = true; } @Override public void onNodesUpdated(List<NodeReport> updatedNodes) { if (updatedNodes != null && !updatedNodes.isEmpty()) { for (NodeReport nodeReport : updatedNodes) { LOG.info("updateNodes > {}", nodeReport.getNodeId().getHost()); } } } @Override public float getProgress() { // set progress to deliver to RM on next heartbeat float progress = (float) numCompletedContainers.get() / numTotalContainers; return progress; } @Override public void onError(Throwable e) { LOG.error("RMCallbackHandler", e); done = true; amRMClient.stop(); } } @VisibleForTesting static class NMCallbackHandler implements NMClientAsync.CallbackHandler { private ConcurrentMap<ContainerId, Container> containers = new ConcurrentHashMap<ContainerId, Container>(); private final FetchApplication fetchApplication; public NMCallbackHandler(FetchApplication fetchApplication) { this.fetchApplication = fetchApplication; } public void addContainer(ContainerId containerId, Container container) { containers.putIfAbsent(containerId, container); } @Override public void onContainerStopped(ContainerId containerId) { if (LOG.isDebugEnabled()) { LOG.debug("Succeeded to stop Container " + containerId); } containers.remove(containerId); } @Override public void onContainerStatusReceived(ContainerId containerId, ContainerStatus containerStatus) { if (LOG.isDebugEnabled()) { LOG.debug("Container Status: id=" + containerId + ", status=" + containerStatus); } } @Override public void onContainerStarted(ContainerId containerId, Map<String, ByteBuffer> allServiceResponse) { if (LOG.isDebugEnabled()) { LOG.debug("Succeeded to first Container {}", containerId); } Container container = containers.get(containerId); if (container != null) { fetchApplication.nmClientAsync.getContainerStatusAsync(containerId, container.getNodeId()); } } @Override public void onStartContainerError(ContainerId containerId, Throwable t) { LOG.error("onStartContainerError", t); LOG.error("Failed to first Container {} ", containerId); containers.remove(containerId); fetchApplication.numCompletedContainers.incrementAndGet(); fetchApplication.numFailedContainers.incrementAndGet(); } @Override public void onGetContainerStatusError(ContainerId containerId, Throwable t) { LOG.error("Failed to query the status of Container " + containerId); } @Override public void onStopContainerError(ContainerId containerId, Throwable t) { LOG.error("Failed to stop Container " + containerId); containers.remove(containerId); } } /** * Thread to connect to the {@link ContainerManagementProtocol} and launch * the container that will execute the shell command. */ private class LaunchContainerRunnable implements Runnable { // Allocated container Container container; NMCallbackHandler containerListener; XPairDto<Long, Long> startEndKeyPair; Long batchId; /** * @param lcontainer * Allocated container * @param containerListener * Callback handler of the container */ public LaunchContainerRunnable(Container lcontainer, NMCallbackHandler containerListener, XPairDto<Long, Long> pair, Long batchId) { this.container = lcontainer; this.containerListener = containerListener; this.startEndKeyPair = pair; this.batchId = batchId; } @Override /** * Connects to CM, sets up container launch context * for shell command and eventually dispatches the container * first request to the CM. */ public void run() { LOG.info("Setting up container launch container for containerid={}", container.getId()); ContainerLaunchContext ctx = Records.newRecord(ContainerLaunchContext.class); Map<String, String> env = new HashMap<String, String>(); for (Entry<String, String> v : System.getenv().entrySet()) { if (!v.getKey().equals("JAVA_HOME")) { env.put(v.getKey(), v.getValue()); } } String localJarDir = conf.get("hadoop.tmp.dir") + "/" + batchId + "/avengers.jar"; env.put("CLASSPATH", System.getenv("CLASSPATH") + ":" + localJarDir); ctx.setEnvironment(env); // Set the local resources Map<String, LocalResource> localResources = new HashMap<String, LocalResource>(); // localResources.put("", value) ctx.setLocalResources(localResources); // Set the necessary command to execute on the allocated // container Vector<CharSequence> vargs = new Vector<CharSequence>(30); vargs.add(Environment.JAVA_HOME.$() + "/bin/java"); // Set Xmx based on am memory size vargs.add("-Xmx" + containerMemory + "m"); // Set executable command vargs.add(Fetch.class.getName()); vargs.add("-start"); vargs.add(String.valueOf(this.startEndKeyPair.getFirst())); vargs.add("-end"); vargs.add(String.valueOf(this.startEndKeyPair.getSecond())); vargs.add("-batchId"); vargs.add(String.valueOf(this.batchId)); vargs.add("1>" + ApplicationConstants.LOG_DIR_EXPANSION_VAR + "/Fetch.stdout"); vargs.add("2>" + ApplicationConstants.LOG_DIR_EXPANSION_VAR + "/Fetch.stderr"); // Get final commmand StringBuilder command = new StringBuilder(); for (CharSequence str : vargs) { command.append(str).append(" "); } LOG.info("command > {},run on node {},containerId is {}", command.toString(), this.container.getNodeId().getHost(), this.container.getId()); List<String> commands = new ArrayList<String>(); commands.add(command.toString()); ctx.setCommands(commands); ctx.setTokens(allTokens.duplicate()); containerListener.addContainer(container.getId(), container); nmClientAsync.startContainerAsync(container, ctx); } } /** * Setup the request that will be sent to the RM for the container ask. * * @return the setup ResourceRequest to be sent to RM */ private ContainerRequest setupContainerAskForRM() { // setup requirements for hosts // using * as any host will do for the distributed shell app // set the priority for the request Priority pri = Records.newRecord(Priority.class); pri.setPriority(requestPriority); // Set up resource type requirements // For now, only memory is supported so we set memory requirements Resource capability = Records.newRecord(Resource.class); capability.setMemory(containerMemory); ContainerRequest request = new ContainerRequest(capability, null, null, pri); LOG.info("Requested container ask: {},request node: {} ", request.toString(), request.getNodes() != null && !request.getNodes().isEmpty() ? request.getNodes().get(0) : ""); return request; } }