/*
* 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.flink.runtime.highavailability;
import org.apache.flink.api.common.JobID;
import org.apache.flink.runtime.blob.BlobStore;
import org.apache.flink.runtime.checkpoint.CheckpointRecoveryFactory;
import org.apache.flink.runtime.jobmanager.SubmittedJobGraphStore;
import org.apache.flink.runtime.leaderelection.LeaderElectionService;
import org.apache.flink.runtime.leaderretrieval.LeaderRetrievalService;
import java.io.IOException;
import java.util.UUID;
/**
* The HighAvailabilityServices give access to all services needed for a highly-available
* setup. In particular, the services provide access to highly available storage and
* registries, as well as distributed counters and leader election.
*
* <ul>
* <li>ResourceManager leader election and leader retrieval</li>
* <li>JobManager leader election and leader retrieval</li>
* <li>Persistence for checkpoint metadata</li>
* <li>Registering the latest completed checkpoint(s)</li>
* <li>Persistence for the BLOB store</li>
* <li>Registry that marks a job's status</li>
* <li>Naming of RPC endpoints</li>
* </ul>
*/
public interface HighAvailabilityServices extends AutoCloseable {
// ------------------------------------------------------------------------
// Constants
// ------------------------------------------------------------------------
/**
* This UUID should be used when no proper leader election happens, but a simple
* pre-configured leader is used. That is for example the case in non-highly-available
* standalone setups.
*/
UUID DEFAULT_LEADER_ID = new UUID(0, 0);
/**
* This JobID should be used to identify the old JobManager when using the
* {@link HighAvailabilityServices}. With Flip-6 every JobManager will have a distinct
* JobID assigned.
*/
JobID DEFAULT_JOB_ID = new JobID(0L, 0L);
// ------------------------------------------------------------------------
// Services
// ------------------------------------------------------------------------
/**
* Gets the leader retriever for the cluster's resource manager.
*/
LeaderRetrievalService getResourceManagerLeaderRetriever();
/**
* Gets the leader retriever for the job JobMaster which is responsible for the given job
*
* @param jobID The identifier of the job.
* @return Leader retrieval service to retrieve the job manager for the given job
*/
LeaderRetrievalService getJobManagerLeaderRetriever(JobID jobID);
/**
* Gets the leader election service for the cluster's resource manager.
*
* @return Leader election service for the resource manager leader election
*/
LeaderElectionService getResourceManagerLeaderElectionService();
/**
* Gets the leader election service for the given job.
*
* @param jobID The identifier of the job running the election.
* @return Leader election service for the job manager leader election
*/
LeaderElectionService getJobManagerLeaderElectionService(JobID jobID);
/**
* Gets the checkpoint recovery factory for the job manager
*
* @return Checkpoint recovery factory
*/
CheckpointRecoveryFactory getCheckpointRecoveryFactory();
/**
* Gets the submitted job graph store for the job manager
*
* @return Submitted job graph store
* @throws Exception if the submitted job graph store could not be created
*/
SubmittedJobGraphStore getSubmittedJobGraphStore() throws Exception;
/**
* Gets the registry that holds information about whether jobs are currently running.
*
* @return Running job registry to retrieve running jobs
*/
RunningJobsRegistry getRunningJobsRegistry() throws Exception;
/**
* Creates the BLOB store in which BLOBs are stored in a highly-available fashion.
*
* @return Blob store
* @throws IOException if the blob store could not be created
*/
BlobStore createBlobStore() throws IOException;
// ------------------------------------------------------------------------
// Shutdown and Cleanup
// ------------------------------------------------------------------------
/**
* Closes the high availability services, releasing all resources.
*
* <p>This method <b>does not delete or clean up</b> any data stored in external stores
* (file systems, ZooKeeper, etc). Another instance of the high availability
* services will be able to recover the job.
*
* <p>If an exception occurs during closing services, this method will attempt to
* continue closing other services and report exceptions only after all services
* have been attempted to be closed.
*
* @throws Exception Thrown, if an exception occurred while closing these services.
*/
@Override
void close() throws Exception;
/**
* Closes the high availability services (releasing all resources) and deletes
* all data stored by these services in external stores.
*
* <p>After this method was called, the any job or session that was managed by
* these high availability services will be unrecoverable.
*
* <p>If an exception occurs during cleanup, this method will attempt to
* continue the cleanup and report exceptions only after all cleanup steps have
* been attempted.
*
* @throws Exception Thrown, if an exception occurred while closing these services
* or cleaning up data stored by them.
*/
void closeAndCleanupAllData() throws Exception;
}