1. 客户端
1)Job.java
用户编辑好的MapReduce程序会通过Job.waitForCompletion(true)提交任务。
public boolean waitForCompletion(boolean verbose
) throws IOException, InterruptedException,
ClassNotFoundException {
// 通过submit()方法提交Job
if (state == JobState.DEFINE) {
submit();
}
if (verbose) {
//在循环中不断得到此任务的状态，并打印到客户端的Console中
monitorAndPrintJob();
} else {
...
}
return isSuccessful();
}
public void submit()
throws IOException, InterruptedException, ClassNotFoundException {
// 确认Job状态
ensureState(JobState.DEFINE);
// 使用YARN的API
setUseNewAPI();
// 初始化用于获取MapReduce程序状态的Cluster，该类会去配置文件中加载是将job提交到Yarn还是JobTracker中
connect();
// 构建用于提交Job的JobSubmitter
final JobSubmitter submitter =
getJobSubmitter(cluster.getFileSystem(), cluster.getClient());
status = ugi.doAs(new PrivilegedExceptionAction<JobStatus>() {
public JobStatus run() throws IOException, InterruptedException,
ClassNotFoundException {
return submitter.submitJobInternal(Job.this, cluster);
}
});
// 更新Job状态
state = JobState.RUNNING;
LOG.info("The url to track the job: " + getTrackingURL());
}
2) JobSubmitter.java
由Job提交的任务将由JobSubmitter接管，在提交前进行一些检查和准备工作
JobStatus submitJobInternal(Job job, Cluster cluster)
throws ClassNotFoundException, InterruptedException, IOException {
// 检查Job的output格式是否符合要求
checkSpecs(job);
Path jobStagingArea = JobSubmissionFiles.getStagingDir(cluster,
job.getConfiguration());
// 确认提交Job时使用的参数是否正确，比如运行该Job的host等
Configuration conf = job.getConfiguration();
InetAddress ip = InetAddress.getLocalHost();
if (ip != null) {
submitHostAddress = ip.getHostAddress();
submitHostName = ip.getHostName();
conf.set(MRJobConfig.JOB_SUBMITHOST,submitHostName);
conf.set(MRJobConfig.JOB_SUBMITHOSTADDR,submitHostAddress);
}
// 从ClientPotocol的实现类获得当前job的id
JobID jobId = submitClient.getNewJobID();
job.setJobID(jobId);
Path submitJobDir = new Path(jobStagingArea, jobId.toString());
JobStatus status = null;
// 将该job任务运行所在的程序的jar包、所要处理的input split信息以及配置项写入HDFS
try {
conf.set("hadoop.http.filter.initializers",
"org.apache.hadoop.yarn.server.webproxy.amfilter.AmFilterInitializer");
conf.set(MRJobConfig.MAPREDUCE_JOB_DIR, submitJobDir.toString());
LOG.debug("Configuring job " + jobId + " with " + submitJobDir
+ " as the submit dir");
TokenCache.obtainTokensForNamenodes(job.getCredentials(),
new Path[] { submitJobDir }, conf);
populateTokenCache(conf, job.getCredentials());
copyAndConfigureFiles(job, submitJobDir);
Path submitJobFile = JobSubmissionFiles.getJobConfPath(submitJobDir);
// 写入Split信息
LOG.debug("Creating splits at " + jtFs.makeQualified(submitJobDir));
int maps = writeSplits(job, submitJobDir);
conf.setInt(MRJobConfig.NUM_MAPS, maps);
LOG.info("number of splits:" + maps);
// 写入Job提交的queue
String queue = conf.get(MRJobConfig.QUEUE_NAME,
JobConf.DEFAULT_QUEUE_NAME);
AccessControlList acl = submitClient.getQueueAdmins(queue);
conf.set(toFullPropertyName(queue,
QueueACL.ADMINISTER_JOBS.getAclName()), acl.getAclString());
// 删除用于提供用户访问的Token
TokenCache.cleanUpTokenReferral(conf);
// 写入配置信息
writeConf(conf, submitJobFile);
printTokens(jobId, job.getCredentials());
// 调用ClientProtocol的submitJob方法提交Job
status = submitClient.submitJob(
jobId, submitJobDir.toString(), job.getCredentials());
...
}
3) YARNRunner.java
在Yarn框架中，将由实现了ClientPotocol的YARNRunner类接管submitJob工作，检查运行条件并初始化运行MRAppMaster的相关信息，向ResourceManager申请Container运行MRAppMaster
public JobStatus submitJob(JobID jobId, String jobSubmitDir, Credentials ts)
throws IOException, InterruptedException {
// 查看是否开启HistoryServer，如果开启则设置相关信息
MRClientProtocol hsProxy = clientCache.getInitializedHSProxy();
if (hsProxy != null) {
if (conf.getBoolean(JobClient.HS_DELEGATION_TOKEN_REQUIRED,
DEFAULT_HS_DELEGATION_TOKEN_REQUIRED)) {
Token hsDT = getDelegationTokenFromHS(hsProxy, new Text(
conf.get(JobClient.HS_DELEGATION_TOKEN_RENEWER)));
ts.addToken(hsDT.getService(), hsDT);
}
}
// 写入Job相关文件的相关信息：文件大小等
Path applicationTokensFile =
new Path(jobSubmitDir, MRJobConfig.APPLICATION_TOKENS_FILE);
try {
ts.writeTokenStorageFile(applicationTokensFile, conf);
} catch (IOException e) {
throw new YarnException(e);
}
/* 初始化Application上下文
ApplicationId
ApplicationName
Queue：Application将被提交到的队列
Priority：Application的优先级
User：运行MRAppMaster的用户
AMContainerSpec：运行ApplicationMaster的Container的信息
ContainerId
User：运行MRAppMaster的用户
Resource：ResourceManager分配给该MRAppMaster的资源
ContainerToken：Security模式下的SecurityTokens
LocalResources：MRAppMaster所在的jar包、Job的配置文件、Job程序所在的jar包、每个Split的相关信息等
ServiceData：
Environment：运行MRAppMaster的ClassPath以及其他的环境便令
Commands：运行MRAppMaster的Command，如：$JAVA_HOME/bin/java MRAppMaster.class.getName() ...
ApplicationACLs：MRAppMaster的访问控制列表
*/
ApplicationSubmissionContext appContext =
createApplicationSubmissionContext(conf, jobSubmitDir, ts);
// 由ResourceMgrDelegate提交给ResourceManager
ApplicationId applicationId = resMgrDelegate.submitApplication(appContext);
// 由ResourceMgrDelegate获取MRAppMaster的运行信息
ApplicationReport appMaster = resMgrDelegate
.getApplicationReport(applicationId);
...
return clientCache.getClient(jobId).getJobStatus(jobId);
}
4) ResourceMgrDelegate.java
ResourceMgrDelegate负责和ResourceManager的通信，并向ResourceManager提交启动ApplicationMaster(MRAppMaster)
// 连接ResourceManager
public ResourceMgrDelegate(YarnConfiguration conf) {
this.conf = conf;
YarnRPC rpc = YarnRPC.create(this.conf);
InetSocketAddress rmAddress =
NetUtils.createSocketAddr(this.conf.get(
YarnConfiguration.RM_ADDRESS,
YarnConfiguration.DEFAULT_RM_ADDRESS),
YarnConfiguration.DEFAULT_RM_PORT,
YarnConfiguration.RM_ADDRESS);
this.rmAddress = rmAddress.toString();
LOG.debug("Connecting to ResourceManager at " + rmAddress);
applicationsManager =
(ClientRMProtocol) rpc.getProxy(ClientRMProtocol.class,
rmAddress, this.conf);
LOG.debug("Connected to ResourceManager at " + rmAddress);
}
// 获取一个Application
public JobID getNewJobID() throws IOException, InterruptedException {
GetNewApplicationRequest request = recordFactory.newRecordInstance(GetNewApplicationRequest.class);
applicationId = applicationsManager.getNewApplication(request).getApplicationId();
// TypeConverter类用于对Yarn格式的Job信息和旧版本Hadoop的Job信息进行转换，比如JobId、ApplicationId、TaskId等
return TypeConverter.fromYarn(applicationId);
}
// 将Application提交到ResourceManager，ResourceManager将分配Container运行MRAppMaster
public ApplicationId submitApplication(
ApplicationSubmissionContext appContext)
throws IOException {
appContext.setApplicationId(applicationId);
SubmitApplicationRequest request =
recordFactory.newRecordInstance(SubmitApplicationRequest.class);
request.setApplicationSubmissionContext(appContext);
applicationsManager.submitApplication(request);
LOG.info("Submitted application " + applicationId + " to ResourceManager" +
" at " + rmAddress);
return applicationId;
}
// 向ResourceManager询问Application运行的信息
public ApplicationReport getApplicationReport(ApplicationId appId)
throws YarnRemoteException {
GetApplicationReportRequest request = recordFactory
.newRecordInstance(GetApplicationReportRequest.class);
request.setApplicationId(appId);
GetApplicationReportResponse response = applicationsManager
.getApplicationReport(request);
ApplicationReport applicationReport = response.getApplicationReport();
return applicationReport;
}
至此Client端(即提交Job的机器)的工作结束，接下来将由ResourceManager接管，分配Container运行MRAppMaster
2. Server端(ResourceManager)
To be continued...