Hadoop YARN：ApplicationMaster与ResourceManager交互源码解析

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ApplicationMasterResourceManager

“通用”YARN应用涉及的角色及交互：
RM：ResourceManager
AM：ApplicationMaster
NM：NodeManager
交互中用到的主要通信协议：
ApplicationClientProtocol
ApplicationMasterProtocol
ContainerManagementProtocol
ClientResourceManager
客户端程序与RM进行交互，通过YarnClient对象来实现。
ApplicationMasterResourceManager
AM与RM进行交互，通过AMRMClientAsync对象来实现，
AMRMClientAsync.CallbackHandler异步处理事件信息。
ApplicationMasterNodeManager
AM与NM进行交互，通过NMClientAsync对象来实现，主要是启动Container，
NMClientAsync.CallbackHandler异步处理Container事件。
接口请求和响应的proto message定义：
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/proto/yarn_protos.proto。
Hadoop版本3.2.1
Flink版本1.10
1.以Flink中Yarn per-job模式下
JobManager——
进程YarnJobClusterEntrypoint为例

// 起点是
YarnJobClusterEntrypoint#main
方法

// 落点是
YarnResourceManager

/**

 * The yarn implementation of the resource manager. Used when the system is started

 * via the resource framework YARN.

 */

public class YarnResourceManager extends ActiveResourceManager<YarnWorkerNode>

        implements AMRMClientAsync.CallbackHandler, NMClientAsync.CallbackHandler {

    // 传说中的ApplicationMaster

    ...

    /** resourceManagerClient与ResourceManager进行交互 Client to communicate with the Resource Manager (YARN's master). */

    private AMRMClientAsync resourceManagerClient;




    /** nodeManagerClient与NodeManager进行交互 Client to communicate with the Node manager and launch TaskExecutor processes. */

    private NMClientAsync nodeManagerClient;  

    ...        

}

AMRMClientAsync
abstract class（YARN应用需要自定义实现），用来处理与ResourceManager之间的通信和交互，它提供对事件的异步更新操作，比如Container的分配和资源使用结束。它包含一个线程，定期向ResourceManager发送心跳。
需要通过实现AMRMClientAsync.CallbackHandler回调接口来配合AMRMClientAsync。
2.简单实例MyCallbackHandler

AMRMClientAsync客户端生命周期

3.AMRMClientAsync部分源码

4.AMRMClientAsyncImpl部分源码

5.AMRMClient部分源码

package org.apache.hadoop.yarn.client.api;




import ...




// 抽象类AMRMClient

public abstract class AMRMClient<T extends AMRMClient.ContainerRequest> extends

    AbstractService {

  ...

}

6.AMRMClientImpl部分源码

7.ApplicationMasterProtocol部分源码
ApplicationMasterProtocol接口比较简单，只有三个方法

package org.apache.hadoop.yarn.api;




import ...

// 接口ApplicationMasterProtocol

public interface ApplicationMasterProtocol {

  // 向RM注册自己（AM）

  public RegisterApplicationMasterResponse registerApplicationMaster(RegisterApplicationMasterRequest request) 

  throws YarnException, IOException;

  

  // 告诉RM，让RM注销自己（AM），有可能AM已经成功执行结束，也有可能应用失败了

  public FinishApplicationMasterResponse finishApplicationMaster(FinishApplicationMasterRequest request) 

  throws YarnException, IOException;

  // AM与RM之间的主要接口（方法），处理AllocateRequest并返回AllocateResponse

  // 就是传说中的请求Container，是成批申请和响应的（比如Flink JobManager一次申请3个TaskManager）

  // 最多执行一次，不会重复和过度分配

  public AllocateResponse allocate(AllocateRequest request) 

  throws YarnException, IOException;

}

8.ApplicationMasterProtocolPBClientImpl部分源码

package org.apache.hadoop.yarn.api.impl.pb.client;




import ...




// 客户端ApplicationMasterProtocol接口的实现

public class ApplicationMasterProtocolPBClientImpl implements ApplicationMasterProtocol, Closeable {




  private ApplicationMasterProtocolPB proxy;




  public ApplicationMasterProtocolPBClientImpl(long clientVersion, InetSocketAddress addr,

      Configuration conf) throws IOException {

    RPC.setProtocolEngine(conf, ApplicationMasterProtocolPB.class, ProtobufRpcEngine.class);

    // 底层会调用java.lang.reflect.Proxy#newProxyInstance

    proxy =

        (ApplicationMasterProtocolPB) RPC.getProxy(ApplicationMasterProtocolPB.class, clientVersion,

          addr, conf);

  }

  ...

}

9.ApplicationMasterProtocolPB

package org.apache.hadoop.yarn.api;




import ...




@Private

@Unstable

@ProtocolInfo(protocolName = "org.apache.hadoop.yarn.api.ApplicationMasterProtocolPB",

    protocolVersion = 1)

public interface ApplicationMasterProtocolPB extends ApplicationMasterProtocolService.BlockingInterface {




}

10.ApplicationMasterProtocolService的定义
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-api/src/main/proto/applicationmaster_protocol.proto

option java_package = "org.apache.hadoop.yarn.proto";

option java_outer_classname = "ApplicationMasterProtocol";

option java_generic_services = true;

option java_generate_equals_and_hash = true;

package hadoop.yarn;




import "yarn_service_protos.proto";




service ApplicationMasterProtocolService {

  rpc registerApplicationMaster (RegisterApplicationMasterRequestProto) returns (RegisterApplicationMasterResponseProto);

  rpc finishApplicationMaster (FinishApplicationMasterRequestProto) returns (FinishApplicationMasterResponseProto);

  rpc allocate (AllocateRequestProto) returns (AllocateResponseProto);

}

11.ApplicationMasterProtocolPBServiceImpl部分源码
ApplicationMasterProtocolPB接口的服务端（RM）实现

package org.apache.hadoop.yarn.api.impl.pb.service;




import ...




@Private

public class ApplicationMasterProtocolPBServiceImpl implements ApplicationMasterProtocolPB {




  private ApplicationMasterProtocol real;

  // ResourceManager启动时会通过此构造方法初始化real对象

  public ApplicationMasterProtocolPBServiceImpl(ApplicationMasterProtocol impl) {

    this.real = impl;

  }  

  ...

}

12.ApplicationMasterService部分源码

package org.apache.hadoop.yarn.server.resourcemanager;




import ...




@SuppressWarnings("unchecked")

@Private

public class ApplicationMasterService extends AbstractService implements

    ApplicationMasterProtocol {

  // 最终会调用到这里的方法并返回结果

  ...

}

【END】