| /** |
| * 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.hadoop.mapred; |
| |
| import java.io.IOException; |
| |
| import org.apache.hadoop.classification.InterfaceAudience; |
| import org.apache.hadoop.classification.InterfaceStability; |
| import org.apache.hadoop.ipc.VersionedProtocol; |
| import org.apache.hadoop.mapreduce.MRJobConfig; |
| import org.apache.hadoop.security.KerberosInfo; |
| |
| /** |
| * Protocol that a TaskTracker and the central JobTracker use to communicate. |
| * The JobTracker is the Server, which implements this protocol. |
| */ |
| @KerberosInfo(MRJobConfig.JOB_JOBTRACKER_ID) |
| @InterfaceAudience.Private |
| @InterfaceStability.Stable |
| interface InterTrackerProtocol extends VersionedProtocol { |
| /** |
| * version 3 introduced to replace |
| * emitHearbeat/pollForNewTask/pollForTaskWithClosedJob with |
| * {@link #heartbeat(TaskTrackerStatus, boolean, boolean, boolean, short)} |
| * version 4 changed TaskReport for HADOOP-549. |
| * version 5 introduced that removes locateMapOutputs and instead uses |
| * getTaskCompletionEvents to figure finished maps and fetch the outputs |
| * version 6 adds maxTasks to TaskTrackerStatus for HADOOP-1245 |
| * version 7 replaces maxTasks by maxMapTasks and maxReduceTasks in |
| * TaskTrackerStatus for HADOOP-1274 |
| * Version 8: HeartbeatResponse is added with the next heartbeat interval. |
| * version 9 changes the counter representation for HADOOP-2248 |
| * version 10 changes the TaskStatus representation for HADOOP-2208 |
| * version 11 changes string to JobID in getTaskCompletionEvents(). |
| * version 12 changes the counters representation for HADOOP-1915 |
| * version 13 added call getBuildVersion() for HADOOP-236 |
| * Version 14: replaced getFilesystemName with getSystemDir for HADOOP-3135 |
| * Version 15: Changed format of Task and TaskStatus for HADOOP-153 |
| * Version 16: adds ResourceStatus to TaskTrackerStatus for HADOOP-3759 |
| * Version 17: Changed format of Task and TaskStatus for HADOOP-3150 |
| * Version 18: Changed status message due to changes in TaskStatus |
| * Version 19: Changed heartbeat to piggyback JobTracker restart information |
| so that the TaskTracker can synchronize itself. |
| * Version 20: Changed status message due to changes in TaskStatus |
| * (HADOOP-4232) |
| * Version 21: Changed information reported in TaskTrackerStatus' |
| * ResourceStatus and the corresponding accessor methods |
| * (HADOOP-4035) |
| * Version 22: Replaced parameter 'initialContact' with 'restarted' |
| * in heartbeat method (HADOOP-4305) |
| * Version 23: Added parameter 'initialContact' again in heartbeat method |
| * (HADOOP-4869) |
| * Version 24: Changed format of Task and TaskStatus for HADOOP-4759 |
| * Version 25: JobIDs are passed in response to JobTracker restart |
| * Version 26: Modified TaskID to be aware of the new TaskTypes |
| * Version 27: Added numRequiredSlots to TaskStatus for MAPREDUCE-516 |
| * Version 28: Adding node health status to TaskStatus for MAPREDUCE-211 |
| * Version 29: Adding user name to the serialized Task for use by TT. |
| * Version 30: Adding available memory and CPU usage information on TT to |
| * TaskTrackerStatus for MAPREDUCE-1218 |
| */ |
| public static final long versionID = 30L; |
| |
| public final static int TRACKERS_OK = 0; |
| public final static int UNKNOWN_TASKTRACKER = 1; |
| |
| /** |
| * Called regularly by the {@link TaskTracker} to update the status of its |
| * tasks within the job tracker. {@link JobTracker} responds with a |
| * {@link HeartbeatResponse} that directs the |
| * {@link TaskTracker} to undertake a series of 'actions' |
| * (see {@link org.apache.hadoop.mapred.TaskTrackerAction.ActionType}). |
| * |
| * {@link TaskTracker} must also indicate whether this is the first |
| * interaction (since state refresh) and acknowledge the last response |
| * it recieved from the {@link JobTracker} |
| * |
| * @param status the status update |
| * @param restarted <code>true</code> if the process has just started or |
| * restarted, <code>false</code> otherwise |
| * @param initialContact <code>true</code> if this is first interaction since |
| * 'refresh', <code>false</code> otherwise. |
| * @param acceptNewTasks <code>true</code> if the {@link TaskTracker} is |
| * ready to accept new tasks to run. |
| * @param responseId the last responseId successfully acted upon by the |
| * {@link TaskTracker}. |
| * @return a {@link org.apache.hadoop.mapred.HeartbeatResponse} with |
| * fresh instructions. |
| */ |
| HeartbeatResponse heartbeat(TaskTrackerStatus status, |
| boolean restarted, |
| boolean initialContact, |
| boolean acceptNewTasks, |
| short responseId) |
| throws IOException; |
| |
| /** |
| * The task tracker calls this once, to discern where it can find |
| * files referred to by the JobTracker |
| */ |
| public String getFilesystemName() throws IOException; |
| |
| /** |
| * Report a problem to the job tracker. |
| * @param taskTracker the name of the task tracker |
| * @param errorClass the kind of error (eg. the class that was thrown) |
| * @param errorMessage the human readable error message |
| * @throws IOException if there was a problem in communication or on the |
| * remote side |
| */ |
| public void reportTaskTrackerError(String taskTracker, |
| String errorClass, |
| String errorMessage) throws IOException; |
| /** |
| * Get task completion events for the jobid, starting from fromEventId. |
| * Returns empty aray if no events are available. |
| * @param jobid job id |
| * @param fromEventId event id to start from. |
| * @param maxEvents the max number of events we want to look at |
| * @return array of task completion events. |
| * @throws IOException |
| */ |
| TaskCompletionEvent[] getTaskCompletionEvents(JobID jobid, int fromEventId |
| , int maxEvents) throws IOException; |
| |
| /** |
| * Grab the jobtracker system directory path where job-specific files are to be placed. |
| * |
| * @return the system directory where job-specific files are to be placed. |
| */ |
| public String getSystemDir(); |
| |
| |
| /** |
| * Returns the buildVersion of the JobTracker |
| */ |
| public String getBuildVersion() throws IOException; |
| } |
