hadoop RequestHedgingRMFailoverProxyProvider 源码

  • 2022-10-20
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haddop RequestHedgingRMFailoverProxyProvider 代码


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 * distributed with this work for additional information
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 * 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
 * <p/>
 * http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.hadoop.yarn.client;

import java.io.IOException;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import java.net.InetSocketAddress;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.Callable;
import java.util.concurrent.CompletionService;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorCompletionService;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Future;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.io.retry.RetryPolicy;
import org.apache.hadoop.io.retry.RetryProxy;
import org.apache.hadoop.util.concurrent.HadoopExecutors;
import org.apache.hadoop.yarn.conf.HAUtil;
import org.apache.hadoop.yarn.conf.YarnConfiguration;

 * A FailoverProxyProvider implementation that technically does not "failover"
 * per-se. It constructs a wrapper proxy that sends the request to ALL
 * underlying proxies simultaneously. Each proxy inside the wrapper proxy will
 * retry the corresponding target. It assumes the in an HA setup, there will be
 * only one Active, and the active should respond faster than any configured
 * standbys. Once it receives a response from any one of the configured proxies,
 * outstanding requests to other proxies are immediately cancelled.
public class RequestHedgingRMFailoverProxyProvider<T>
    extends ConfiguredRMFailoverProxyProvider<T> {

  private static final Logger LOG =

  private volatile String successfulProxy = null;
  private ProxyInfo<T> wrappedProxy = null;
  private Map<String, T> nonRetriableProxy = new HashMap<>();

  public void init(Configuration configuration, RMProxy<T> rmProxy,
      Class<T> protocol) {
    super.init(configuration, rmProxy, protocol);
    Map<String, ProxyInfo<T>> retriableProxies = new HashMap<>();

    String originalId = HAUtil.getRMHAId(conf);
    for (String rmId : rmServiceIds) {
      conf.set(YarnConfiguration.RM_HA_ID, rmId);
      nonRetriableProxy.put(rmId, super.getProxyInternal());

      T proxy = createRetriableProxy();
      ProxyInfo<T> pInfo = new ProxyInfo<T>(proxy, rmId);
      retriableProxies.put(rmId, pInfo);
    conf.set(YarnConfiguration.RM_HA_ID, originalId);

    T proxyInstance = (T) Proxy.newProxyInstance(
        new Class<?>[] {protocol},
        new RMRequestHedgingInvocationHandler(retriableProxies));
    String combinedInfo = Arrays.toString(rmServiceIds);
    wrappedProxy = new ProxyInfo<T>(proxyInstance, combinedInfo);
    LOG.info("Created wrapped proxy for " + combinedInfo);

  protected T createRetriableProxy() {
    try {
      // Create proxy that can retry exceptions properly.
      RetryPolicy retryPolicy = RMProxy.createRetryPolicy(conf, false);
      InetSocketAddress rmAddress = rmProxy.getRMAddress(conf, protocol);
      T proxy = rmProxy.getProxy(conf, protocol, rmAddress);
      return (T) RetryProxy.create(protocol, proxy, retryPolicy);
    } catch (IOException ioe) {
      LOG.error("Unable to create proxy to the ResourceManager "
          + HAUtil.getRMHAId(conf), ioe);
      return null;

  class RMRequestHedgingInvocationHandler implements InvocationHandler {

    final private Map<String, ProxyInfo<T>> allProxies;

    public RMRequestHedgingInvocationHandler(
        Map<String, ProxyInfo<T>> allProxies) {
      this.allProxies = new HashMap<>(allProxies);

    protected Object invokeMethod(Object proxy, Method method, Object[] args)
        throws Throwable {
      try {
        return method.invoke(proxy, args);
      } catch (InvocationTargetException ex) {
        throw ex.getCause();

    private Throwable extraRootException(Exception ex) {
      Throwable rootCause = ex;
      if (ex instanceof ExecutionException) {
        Throwable cause = ex.getCause();
        if (cause instanceof InvocationTargetException) {
          rootCause = cause.getCause();
      return rootCause;

     * Creates a Executor and invokes all proxies concurrently.
    public Object invoke(Object proxy, final Method method, final Object[] args)
        throws Throwable {
      if (successfulProxy != null) {
        return invokeMethod(nonRetriableProxy.get(successfulProxy), method,

      LOG.info("Looking for the active RM in " + Arrays.toString(rmServiceIds)
          + "...");
      ExecutorService executor = null;
      CompletionService<Object> completionService;
      try {
        Map<Future<Object>, ProxyInfo<T>> proxyMap = new HashMap<>();
        executor = HadoopExecutors.newFixedThreadPool(allProxies.size());
        completionService = new ExecutorCompletionService<>(executor);
        for (final ProxyInfo<T> pInfo : allProxies.values()) {
          Callable<Object> c = new Callable<Object>() {
            public Object call() throws Exception {
              return method.invoke(pInfo.proxy, args);
          proxyMap.put(completionService.submit(c), pInfo);

        Future<Object> callResultFuture = completionService.take();
        String pInfo = proxyMap.get(callResultFuture).proxyInfo;
        successfulProxy = pInfo;
        Object retVal;
        try {
          retVal = callResultFuture.get();
          LOG.info("Found active RM [" + pInfo + "]");
          return retVal;
        } catch (Exception ex) {
          // Throw exception from first responding RM so that clients can handle
          // appropriately
          Throwable rootCause = extraRootException(ex);
          LOG.warn("Invocation returned exception: " + rootCause.toString()
              + " on " + "[" + pInfo + "], so propagating back to caller.");
          throw rootCause;

      } finally {
        if (executor != null) {

  public ProxyInfo<T> getProxy() {
    return wrappedProxy;

  public void performFailover(T currentProxy) {
    LOG.info("Connection lost with " + successfulProxy + ", trying to fail over.");
    successfulProxy = null;


hadoop 源码目录


hadoop AHSProxy 源码

hadoop AMRMClientUtils 源码

hadoop AutoRefreshNoHARMFailoverProxyProvider 源码

hadoop AutoRefreshRMFailoverProxyProvider 源码

hadoop ClientRMProxy 源码

hadoop ConfiguredRMFailoverProxyProvider 源码

hadoop DefaultNoHARMFailoverProxyProvider 源码

hadoop NMProxy 源码

hadoop RMFailoverProxyProvider 源码

hadoop RMHAServiceTarget 源码

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