聊聊flink JobManager的High Availability

序

本文主要研究一下flink JobManager的High Availability

配置

flink-conf.yaml

high-availability: zookeeper
high-availability.zookeeper.quorum: zookeeper:2181
high-availability.zookeeper.path.root: /flink
high-availability.cluster-id: /cluster_one # important: customize per cluster
high-availability.storageDir: file:///share

• high-availability的可选值为NONE或者zookeeper；high-availability.zookeeper.quorum用于指定zookeeper的peers；high-availability.zookeeper.path.root用于指定在zookeeper的root node路径；high-availability.cluster-id用于指定当前cluster的node名称，该cluster node位于root node下面；high-availability.storageDir用于指定JobManager metadata的存储路径

masters文件

localhost:8081
localhost:8082

• masters文件用于指定jobmanager的地址

HighAvailabilityMode

flink-runtime_2.11-1.7.1-sources.jar!/org/apache/flink/runtime/jobmanager/HighAvailabilityMode.java

public enum HighAvailabilityMode {
    NONE(false),
    ZOOKEEPER(true),
    FACTORY_CLASS(true);

    private final boolean haActive;

    HighAvailabilityMode(boolean haActive) {
        this.haActive = haActive;
    }

    /**
     * Return the configured {@link HighAvailabilityMode}.
     *
     * @param config The config to parse
     * @return Configured recovery mode or {@link HighAvailabilityMode#NONE} if not
     * configured.
     */
    public static HighAvailabilityMode fromConfig(Configuration config) {
        String haMode = config.getValue(HighAvailabilityOptions.HA_MODE);

        if (haMode == null) {
            return HighAvailabilityMode.NONE;
        } else if (haMode.equalsIgnoreCase(ConfigConstants.DEFAULT_RECOVERY_MODE)) {
            // Map old default to new default
            return HighAvailabilityMode.NONE;
        } else {
            try {
                return HighAvailabilityMode.valueOf(haMode.toUpperCase());
            } catch (IllegalArgumentException e) {
                return FACTORY_CLASS;
            }
        }
    }

    /**
     * Returns true if the defined recovery mode supports high availability.
     *
     * @param configuration Configuration which contains the recovery mode
     * @return true if high availability is supported by the recovery mode, otherwise false
     */
    public static boolean isHighAvailabilityModeActivated(Configuration configuration) {
        HighAvailabilityMode mode = fromConfig(configuration);
        return mode.haActive;
    }
}

• HighAvailabilityMode有三个枚举，分别是NONE、ZOOKEEPER、FACTORY_CLASS；这些枚举有一个属性haActive，用于表示是否支持HighAvailability

HighAvailabilityOptions

flink-core-1.7.1-sources.jar!/org/apache/flink/configuration/HighAvailabilityOptions.java

@PublicEvolving
@ConfigGroups(groups = {
    @ConfigGroup(name = "HighAvailabilityZookeeper", keyPrefix = "high-availability.zookeeper")
})
public class HighAvailabilityOptions {

    // ------------------------------------------------------------------------
    //  Required High Availability Options
    // ------------------------------------------------------------------------

    /**
     * Defines high-availability mode used for the cluster execution.
     * A value of "NONE" signals no highly available setup.
     * To enable high-availability, set this mode to "ZOOKEEPER".
     * Can also be set to FQN of HighAvailability factory class.
     */
    @Documentation.CommonOption(position = Documentation.CommonOption.POSITION_HIGH_AVAILABILITY)
    public static final ConfigOption<String> HA_MODE =
            key("high-availability")
            .defaultValue("NONE")
            .withDeprecatedKeys("recovery.mode")
            .withDescription("Defines high-availability mode used for the cluster execution." +
                " To enable high-availability, set this mode to \"ZOOKEEPER\" or specify FQN of factory class.");

    /**
     * The ID of the Flink cluster, used to separate multiple Flink clusters
     * Needs to be set for standalone clusters, is automatically inferred in YARN and Mesos.
     */
    public static final ConfigOption<String> HA_CLUSTER_ID =
            key("high-availability.cluster-id")
            .defaultValue("/default")
            .withDeprecatedKeys("high-availability.zookeeper.path.namespace", "recovery.zookeeper.path.namespace")
            .withDescription("The ID of the Flink cluster, used to separate multiple Flink clusters from each other." +
                " Needs to be set for standalone clusters but is automatically inferred in YARN and Mesos.");

    /**
     * File system path (URI) where Flink persists metadata in high-availability setups.
     */
    @Documentation.CommonOption(position = Documentation.CommonOption.POSITION_HIGH_AVAILABILITY)
    public static final ConfigOption<String> HA_STORAGE_PATH =
            key("high-availability.storageDir")
            .noDefaultValue()
            .withDeprecatedKeys("high-availability.zookeeper.storageDir", "recovery.zookeeper.storageDir")
            .withDescription("File system path (URI) where Flink persists metadata in high-availability setups.");

    // ------------------------------------------------------------------------
    //  Recovery Options
    // ------------------------------------------------------------------------

    /**
     * Optional port (range) used by the job manager in high-availability mode.
     */
    public static final ConfigOption<String> HA_JOB_MANAGER_PORT_RANGE =
            key("high-availability.jobmanager.port")
            .defaultValue("0")
            .withDeprecatedKeys("recovery.jobmanager.port")
            .withDescription("Optional port (range) used by the job manager in high-availability mode.");

    /**
     * The time before a JobManager after a fail over recovers the current jobs.
     */
    public static final ConfigOption<String> HA_JOB_DELAY =
            key("high-availability.job.delay")
            .noDefaultValue()
            .withDeprecatedKeys("recovery.job.delay")
            .withDescription("The time before a JobManager after a fail over recovers the current jobs.");

    // ------------------------------------------------------------------------
    //  ZooKeeper Options
    // ------------------------------------------------------------------------

    /**
     * The ZooKeeper quorum to use, when running Flink in a high-availability mode with ZooKeeper.
     */
    public static final ConfigOption<String> HA_ZOOKEEPER_QUORUM =
            key("high-availability.zookeeper.quorum")
            .noDefaultValue()
            .withDeprecatedKeys("recovery.zookeeper.quorum")
            .withDescription("The ZooKeeper quorum to use, when running Flink in a high-availability mode with ZooKeeper.");

    /**
     * The root path under which Flink stores its entries in ZooKeeper.
     */
    public static final ConfigOption<String> HA_ZOOKEEPER_ROOT =
            key("high-availability.zookeeper.path.root")
            .defaultValue("/flink")
            .withDeprecatedKeys("recovery.zookeeper.path.root")
            .withDescription("The root path under which Flink stores its entries in ZooKeeper.");

    public static final ConfigOption<String> HA_ZOOKEEPER_LATCH_PATH =
            key("high-availability.zookeeper.path.latch")
            .defaultValue("/leaderlatch")
            .withDeprecatedKeys("recovery.zookeeper.path.latch")
            .withDescription("Defines the znode of the leader latch which is used to elect the leader.");

    /** ZooKeeper root path (ZNode) for job graphs. */
    public static final ConfigOption<String> HA_ZOOKEEPER_JOBGRAPHS_PATH =
            key("high-availability.zookeeper.path.jobgraphs")
            .defaultValue("/jobgraphs")
            .withDeprecatedKeys("recovery.zookeeper.path.jobgraphs")
            .withDescription("ZooKeeper root path (ZNode) for job graphs");

    public static final ConfigOption<String> HA_ZOOKEEPER_LEADER_PATH =
            key("high-availability.zookeeper.path.leader")
            .defaultValue("/leader")
            .withDeprecatedKeys("recovery.zookeeper.path.leader")
            .withDescription("Defines the znode of the leader which contains the URL to the leader and the current" +
                " leader session ID.");

    /** ZooKeeper root path (ZNode) for completed checkpoints. */
    public static final ConfigOption<String> HA_ZOOKEEPER_CHECKPOINTS_PATH =
            key("high-availability.zookeeper.path.checkpoints")
            .defaultValue("/checkpoints")
            .withDeprecatedKeys("recovery.zookeeper.path.checkpoints")
            .withDescription("ZooKeeper root path (ZNode) for completed checkpoints.");

    /** ZooKeeper root path (ZNode) for checkpoint counters. */
    public static final ConfigOption<String> HA_ZOOKEEPER_CHECKPOINT_COUNTER_PATH =
            key("high-availability.zookeeper.path.checkpoint-counter")
            .defaultValue("/checkpoint-counter")
            .withDeprecatedKeys("recovery.zookeeper.path.checkpoint-counter")
            .withDescription("ZooKeeper root path (ZNode) for checkpoint counters.");

    /** ZooKeeper root path (ZNode) for Mesos workers. */
    @PublicEvolving
    public static final ConfigOption<String> HA_ZOOKEEPER_MESOS_WORKERS_PATH =
            key("high-availability.zookeeper.path.mesos-workers")
            .defaultValue("/mesos-workers")
            .withDeprecatedKeys("recovery.zookeeper.path.mesos-workers")
            .withDescription(Description.builder()
                .text("The ZooKeeper root path for persisting the Mesos worker information.")
                .build());

    // ------------------------------------------------------------------------
    //  ZooKeeper Client Settings
    // ------------------------------------------------------------------------

    public static final ConfigOption<Integer> ZOOKEEPER_SESSION_TIMEOUT =
            key("high-availability.zookeeper.client.session-timeout")
            .defaultValue(60000)
            .withDeprecatedKeys("recovery.zookeeper.client.session-timeout")
            .withDescription("Defines the session timeout for the ZooKeeper session in ms.");

    public static final ConfigOption<Integer> ZOOKEEPER_CONNECTION_TIMEOUT =
            key("high-availability.zookeeper.client.connection-timeout")
            .defaultValue(15000)
            .withDeprecatedKeys("recovery.zookeeper.client.connection-timeout")
            .withDescription("Defines the connection timeout for ZooKeeper in ms.");

    public static final ConfigOption<Integer> ZOOKEEPER_RETRY_WAIT =
            key("high-availability.zookeeper.client.retry-wait")
            .defaultValue(5000)
            .withDeprecatedKeys("recovery.zookeeper.client.retry-wait")
            .withDescription("Defines the pause between consecutive retries in ms.");

    public static final ConfigOption<Integer> ZOOKEEPER_MAX_RETRY_ATTEMPTS =
            key("high-availability.zookeeper.client.max-retry-attempts")
            .defaultValue(3)
            .withDeprecatedKeys("recovery.zookeeper.client.max-retry-attempts")
            .withDescription("Defines the number of connection retries before the client gives up.");

    public static final ConfigOption<String> ZOOKEEPER_RUNNING_JOB_REGISTRY_PATH =
            key("high-availability.zookeeper.path.running-registry")
            .defaultValue("/running_job_registry/");

    public static final ConfigOption<String> ZOOKEEPER_CLIENT_ACL =
            key("high-availability.zookeeper.client.acl")
            .defaultValue("open")
            .withDescription("Defines the ACL (open|creator) to be configured on ZK node. The configuration value can be" +
                " set to “creator” if the ZooKeeper server configuration has the “authProvider” property mapped to use" +
                " SASLAuthenticationProvider and the cluster is configured to run in secure mode (Kerberos).");

    // ------------------------------------------------------------------------

    /** Not intended to be instantiated. */
    private HighAvailabilityOptions() {}
}

• HighAvailabilityOptions定义了前缀为high-availability.zookeeper的配置项

HighAvailabilityServicesUtils

flink-runtime_2.11-1.7.1-sources.jar!/org/apache/flink/runtime/highavailability/HighAvailabilityServicesUtils.java

public class HighAvailabilityServicesUtils {

    public static HighAvailabilityServices createAvailableOrEmbeddedServices(
        Configuration config,
        Executor executor) throws Exception {
        HighAvailabilityMode highAvailabilityMode = LeaderRetrievalUtils.getRecoveryMode(config);

        switch (highAvailabilityMode) {
            case NONE:
                return new EmbeddedHaServices(executor);

            case ZOOKEEPER:
                BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(config);

                return new ZooKeeperHaServices(
                    ZooKeeperUtils.startCuratorFramework(config),
                    executor,
                    config,
                    blobStoreService);

            case FACTORY_CLASS:
                return createCustomHAServices(config, executor);

            default:
                throw new Exception("High availability mode " + highAvailabilityMode + " is not supported.");
        }
    }

    public static HighAvailabilityServices createHighAvailabilityServices(
        Configuration configuration,
        Executor executor,
        AddressResolution addressResolution) throws Exception {

        HighAvailabilityMode highAvailabilityMode = LeaderRetrievalUtils.getRecoveryMode(configuration);

        switch (highAvailabilityMode) {
            case NONE:
                final Tuple2<String, Integer> hostnamePort = getJobManagerAddress(configuration);

                final String jobManagerRpcUrl = AkkaRpcServiceUtils.getRpcUrl(
                    hostnamePort.f0,
                    hostnamePort.f1,
                    JobMaster.JOB_MANAGER_NAME,
                    addressResolution,
                    configuration);
                final String resourceManagerRpcUrl = AkkaRpcServiceUtils.getRpcUrl(
                    hostnamePort.f0,
                    hostnamePort.f1,
                    ResourceManager.RESOURCE_MANAGER_NAME,
                    addressResolution,
                    configuration);
                final String dispatcherRpcUrl = AkkaRpcServiceUtils.getRpcUrl(
                    hostnamePort.f0,
                    hostnamePort.f1,
                    Dispatcher.DISPATCHER_NAME,
                    addressResolution,
                    configuration);

                final String address = checkNotNull(configuration.getString(RestOptions.ADDRESS),
                    "%s must be set",
                    RestOptions.ADDRESS.key());
                final int port = configuration.getInteger(RestOptions.PORT);
                final boolean enableSSL = SSLUtils.isRestSSLEnabled(configuration);
                final String protocol = enableSSL ? "https://" : "http://";

                return new StandaloneHaServices(
                    resourceManagerRpcUrl,
                    dispatcherRpcUrl,
                    jobManagerRpcUrl,
                    String.format("%s%s:%s", protocol, address, port));
            case ZOOKEEPER:
                BlobStoreService blobStoreService = BlobUtils.createBlobStoreFromConfig(configuration);

                return new ZooKeeperHaServices(
                    ZooKeeperUtils.startCuratorFramework(configuration),
                    executor,
                    configuration,
                    blobStoreService);

            case FACTORY_CLASS:
                return createCustomHAServices(configuration, executor);

            default:
                throw new Exception("Recovery mode " + highAvailabilityMode + " is not supported.");
        }
    }

    /**
     * Returns the JobManager's hostname and port extracted from the given
     * {@link Configuration}.
     *
     * @param configuration Configuration to extract the JobManager's address from
     * @return The JobManager's hostname and port
     * @throws ConfigurationException if the JobManager's address cannot be extracted from the configuration
     */
    public static Tuple2<String, Integer> getJobManagerAddress(Configuration configuration) throws ConfigurationException {

        final String hostname = configuration.getString(JobManagerOptions.ADDRESS);
        final int port = configuration.getInteger(JobManagerOptions.PORT);

        if (hostname == null) {
            throw new ConfigurationException("Config parameter '" + JobManagerOptions.ADDRESS +
                "' is missing (hostname/address of JobManager to connect to).");
        }

        if (port <= 0 || port >= 65536) {
            throw new ConfigurationException("Invalid value for '" + JobManagerOptions.PORT +
                "' (port of the JobManager actor system) : " + port +
                ".  it must be greater than 0 and less than 65536.");
        }

        return Tuple2.of(hostname, port);
    }

    private static HighAvailabilityServices createCustomHAServices(Configuration config, Executor executor) throws FlinkException {
        final ClassLoader classLoader = Thread.currentThread().getContextClassLoader();
        final String haServicesClassName = config.getString(HighAvailabilityOptions.HA_MODE);

        final HighAvailabilityServicesFactory highAvailabilityServicesFactory;

        try {
            highAvailabilityServicesFactory = InstantiationUtil.instantiate(
                haServicesClassName,
                HighAvailabilityServicesFactory.class,
                classLoader);
        } catch (Exception e) {
            throw new FlinkException(
                String.format(
                    "Could not instantiate the HighAvailabilityServicesFactory '%s'. Please make sure that this class is on your class path.",
                    haServicesClassName),
                e);
        }

        try {
            return highAvailabilityServicesFactory.createHAServices(config, executor);
        } catch (Exception e) {
            throw new FlinkException(
                String.format(
                    "Could not create the ha services from the instantiated HighAvailabilityServicesFactory %s.",
                    haServicesClassName),
                e);
        }
    }

    /**
     * Enum specifying whether address resolution should be tried or not when creating the
     * {@link HighAvailabilityServices}.
     */
    public enum AddressResolution {
        TRY_ADDRESS_RESOLUTION,
        NO_ADDRESS_RESOLUTION
    }
}

• HighAvailabilityServicesUtils提供了创建HighAvailabilityServices的静态方法，这些方法有createAvailableOrEmbeddedServices、createHighAvailabilityServices、createCustomHAServices
• 其中createAvailableOrEmbeddedServices方法主要是给FlinkMiniCluster使用；createHighAvailabilityServices方法主要是给ClusterEntrypoint使用，它在highAvailabilityMode为NONE的时候创建的是StandaloneHaServices，在highAvailabilityMode为ZOOKEEPER创建的是ZooKeeperHaServices，在highAvailabilityMode为FACTORY_CLASS的时候使用createCustomHAServices方法来创建
• HighAvailabilityServicesUtils还提供了getJobManagerAddress静态方法，用于获取JobManager的hostname及port

HighAvailabilityServices

flink-runtime_2.11-1.7.1-sources.jar!/org/apache/flink/runtime/highavailability/HighAvailabilityServices.java

/**
 * 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 the new mode every JobMaster 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 dispatcher. This leader retrieval service
     * is not always accessible.
     */
    LeaderRetrievalService getDispatcherLeaderRetriever();

    /**
     * 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
     * @deprecated This method should only be used by the legacy code where the JobManager acts as the master.
     */
    @Deprecated
    LeaderRetrievalService getJobManagerLeaderRetriever(JobID jobID);

    /**
     * Gets the leader retriever for the job JobMaster which is responsible for the given job
     *
     * @param jobID The identifier of the job.
     * @param defaultJobManagerAddress JobManager address which will be returned by
     *                              a static leader retrieval service.
     * @return Leader retrieval service to retrieve the job manager for the given job
     */
    LeaderRetrievalService getJobManagerLeaderRetriever(JobID jobID, String defaultJobManagerAddress);

    LeaderRetrievalService getWebMonitorLeaderRetriever();

    /**
     * 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 cluster's dispatcher.
     *
     * @return Leader election service for the dispatcher leader election
     */
    LeaderElectionService getDispatcherLeaderElectionService();

    /**
     * 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);

    LeaderElectionService getWebMonitorLeaderElectionService();

    /**
     * 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;
}

• HighAvailabilityServices定义了highly-available所需的各种services的get方法

ZooKeeperHaServices

flink-runtime_2.11-1.7.1-sources.jar!/org/apache/flink/runtime/highavailability/zookeeper/ZooKeeperHaServices.java

/**
 * An implementation of the {@link HighAvailabilityServices} using Apache ZooKeeper.
 * The services store data in ZooKeeper's nodes as illustrated by teh following tree structure:
 * 
 * <pre>
 * /flink
 *      +/cluster_id_1/resource_manager_lock
 *      |            |
 *      |            +/job-id-1/job_manager_lock
 *      |            |         /checkpoints/latest
 *      |            |                     /latest-1
 *      |            |                     /latest-2
 *      |            |
 *      |            +/job-id-2/job_manager_lock
 *      |      
 *      +/cluster_id_2/resource_manager_lock
 *                   |
 *                   +/job-id-1/job_manager_lock
 *                            |/checkpoints/latest
 *                            |            /latest-1
 *                            |/persisted_job_graph
 * </pre>
 * 
 * <p>The root path "/flink" is configurable via the option {@link HighAvailabilityOptions#HA_ZOOKEEPER_ROOT}.
 * This makes sure Flink stores its data under specific subtrees in ZooKeeper, for example to
 * accommodate specific permission.
 * 
 * <p>The "cluster_id" part identifies the data stored for a specific Flink "cluster". 
 * This "cluster" can be either a standalone or containerized Flink cluster, or it can be job
 * on a framework like YARN or Mesos (in a "per-job-cluster" mode).
 * 
 * <p>In case of a "per-job-cluster" on YARN or Mesos, the cluster-id is generated and configured
 * automatically by the client or dispatcher that submits the Job to YARN or Mesos.
 * 
 * <p>In the case of a standalone cluster, that cluster-id needs to be configured via
 * {@link HighAvailabilityOptions#HA_CLUSTER_ID}. All nodes with the same cluster id will join the same
 * cluster and participate in the execution of the same set of jobs.
 */
public class ZooKeeperHaServices implements HighAvailabilityServices {

    private static final Logger LOG = LoggerFactory.getLogger(ZooKeeperHaServices.class);

    private static final String RESOURCE_MANAGER_LEADER_PATH = "/resource_manager_lock";

    private static final String DISPATCHER_LEADER_PATH = "/dispatcher_lock";

    private static final String JOB_MANAGER_LEADER_PATH = "/job_manager_lock";

    private static final String REST_SERVER_LEADER_PATH = "/rest_server_lock";

    // ------------------------------------------------------------------------
    
    
    /** The ZooKeeper client to use */
    private final CuratorFramework client;

    /** The executor to run ZooKeeper callbacks on */
    private final Executor executor;

    /** The runtime configuration */
    private final Configuration configuration;

    /** The zookeeper based running jobs registry */
    private final RunningJobsRegistry runningJobsRegistry;

    /** Store for arbitrary blobs */
    private final BlobStoreService blobStoreService;

    public ZooKeeperHaServices(
            CuratorFramework client,
            Executor executor,
            Configuration configuration,
            BlobStoreService blobStoreService) {
        this.client = checkNotNull(client);
        this.executor = checkNotNull(executor);
        this.configuration = checkNotNull(configuration);
        this.runningJobsRegistry = new ZooKeeperRunningJobsRegistry(client, configuration);

        this.blobStoreService = checkNotNull(blobStoreService);
    }

    // ------------------------------------------------------------------------
    //  Services
    // ------------------------------------------------------------------------

    @Override
    public LeaderRetrievalService getResourceManagerLeaderRetriever() {
        return ZooKeeperUtils.createLeaderRetrievalService(client, configuration, RESOURCE_MANAGER_LEADER_PATH);
    }

    @Override
    public LeaderRetrievalService getDispatcherLeaderRetriever() {
        return ZooKeeperUtils.createLeaderRetrievalService(client, configuration, DISPATCHER_LEADER_PATH);
    }

    @Override
    public LeaderRetrievalService getJobManagerLeaderRetriever(JobID jobID) {
        return ZooKeeperUtils.createLeaderRetrievalService(client, configuration, getPathForJobManager(jobID));
    }

    @Override
    public LeaderRetrievalService getJobManagerLeaderRetriever(JobID jobID, String defaultJobManagerAddress) {
        return getJobManagerLeaderRetriever(jobID);
    }

    @Override
    public LeaderRetrievalService getWebMonitorLeaderRetriever() {
        return ZooKeeperUtils.createLeaderRetrievalService(client, configuration, REST_SERVER_LEADER_PATH);
    }

    @Override
    public LeaderElectionService getResourceManagerLeaderElectionService() {
        return ZooKeeperUtils.createLeaderElectionService(client, configuration, RESOURCE_MANAGER_LEADER_PATH);
    }

    @Override
    public LeaderElectionService getDispatcherLeaderElectionService() {
        return ZooKeeperUtils.createLeaderElectionService(client, configuration, DISPATCHER_LEADER_PATH);
    }

    @Override
    public LeaderElectionService getJobManagerLeaderElectionService(JobID jobID) {
        return ZooKeeperUtils.createLeaderElectionService(client, configuration, getPathForJobManager(jobID));
    }

    @Override
    public LeaderElectionService getWebMonitorLeaderElectionService() {
        return ZooKeeperUtils.createLeaderElectionService(client, configuration, REST_SERVER_LEADER_PATH);
    }

    @Override
    public CheckpointRecoveryFactory getCheckpointRecoveryFactory() {
        return new ZooKeeperCheckpointRecoveryFactory(client, configuration, executor);
    }

    @Override
    public SubmittedJobGraphStore getSubmittedJobGraphStore() throws Exception {
        return ZooKeeperUtils.createSubmittedJobGraphs(client, configuration);
    }

    @Override
    public RunningJobsRegistry getRunningJobsRegistry() {
        return runningJobsRegistry;
    }

    @Override
    public BlobStore createBlobStore() throws IOException {
        return blobStoreService;
    }

    // ------------------------------------------------------------------------
    //  Shutdown
    // ------------------------------------------------------------------------

    @Override
    public void close() throws Exception {
        Throwable exception = null;

        try {
            blobStoreService.close();
        } catch (Throwable t) {
            exception = t;
        }

        internalClose();

        if (exception != null) {
            ExceptionUtils.rethrowException(exception, "Could not properly close the ZooKeeperHaServices.");
        }
    }

    @Override
    public void closeAndCleanupAllData() throws Exception {
        LOG.info("Close and clean up all data for ZooKeeperHaServices.");

        Throwable exception = null;

        try {
            blobStoreService.closeAndCleanupAllData();
        } catch (Throwable t) {
            exception = t;
        }

        internalClose();

        if (exception != null) {
            ExceptionUtils.rethrowException(exception, "Could not properly close and clean up all data of ZooKeeperHaServices.");
        }
    }

    /**
     * Closes components which don't distinguish between close and closeAndCleanupAllData
     */
    private void internalClose() {
        client.close();
    }

    // ------------------------------------------------------------------------
    //  Utilities
    // ------------------------------------------------------------------------

    private static String getPathForJobManager(final JobID jobID) {
        return "/" + jobID + JOB_MANAGER_LEADER_PATH;
    }
}

• ZooKeeperHaServices实现了HighAvailabilityServices接口，它通过ZooKeeperUtils的各种create方法来创建所需的service，比如ZooKeeperUtils.createLeaderRetrievalService、ZooKeeperUtils.createLeaderElectionService、ZooKeeperUtils.createSubmittedJobGraphs

JobClient.submitJob

flink-runtime_2.11-1.7.1-sources.jar!/org/apache/flink/runtime/client/JobClient.java

public class JobClient {

    private static final Logger LOG = LoggerFactory.getLogger(JobClient.class);

    //......

    /**
     * Submits a job to a Flink cluster (non-blocking) and returns a JobListeningContext which can be
     * passed to {@code awaitJobResult} to get the result of the submission.
     * @return JobListeningContext which may be used to retrieve the JobExecutionResult via
     *             {@code awaitJobResult(JobListeningContext context)}.
     */
    public static JobListeningContext submitJob(
            ActorSystem actorSystem,
            Configuration config,
            HighAvailabilityServices highAvailabilityServices,
            JobGraph jobGraph,
            FiniteDuration timeout,
            boolean sysoutLogUpdates,
            ClassLoader classLoader) {

        checkNotNull(actorSystem, "The actorSystem must not be null.");
        checkNotNull(highAvailabilityServices, "The high availability services must not be null.");
        checkNotNull(jobGraph, "The jobGraph must not be null.");
        checkNotNull(timeout, "The timeout must not be null.");

        // for this job, we create a proxy JobClientActor that deals with all communication with
        // the JobManager. It forwards the job submission, checks the success/failure responses, logs
        // update messages, watches for disconnect between client and JobManager, ...

        Props jobClientActorProps = JobSubmissionClientActor.createActorProps(
            highAvailabilityServices.getJobManagerLeaderRetriever(HighAvailabilityServices.DEFAULT_JOB_ID),
            timeout,
            sysoutLogUpdates,
            config);

        ActorRef jobClientActor = actorSystem.actorOf(jobClientActorProps);

        Future<Object> submissionFuture = Patterns.ask(
                jobClientActor,
                new JobClientMessages.SubmitJobAndWait(jobGraph),
                new Timeout(AkkaUtils.INF_TIMEOUT()));

        return new JobListeningContext(
            jobGraph.getJobID(),
            submissionFuture,
            jobClientActor,
            timeout,
            classLoader,
            highAvailabilityServices);
    }

    //......
}

• 像JobClient.submitJob方法就使用到了highAvailabilityServices.getJobManagerLeaderRetriever方法来获取JobManagerLeader的地址，用于提交job

小结

• HighAvailabilityMode有三个枚举，分别是NONE、ZOOKEEPER、FACTORY_CLASS；这些枚举有一个属性haActive，用于表示是否支持HighAvailability；HighAvailabilityOptions定义了前缀为high-availability.zookeeper的配置项
• HighAvailabilityServicesUtils提供了创建HighAvailabilityServices的静态方法，这些方法有createAvailableOrEmbeddedServices、createHighAvailabilityServices、createCustomHAServices；其中createAvailableOrEmbeddedServices方法主要是给FlinkMiniCluster使用；createHighAvailabilityServices方法主要是给ClusterEntrypoint使用，它在highAvailabilityMode为NONE的时候创建的是StandaloneHaServices，在highAvailabilityMode为ZOOKEEPER创建的是ZooKeeperHaServices，在highAvailabilityMode为FACTORY_CLASS的时候使用createCustomHAServices方法来创建
• HighAvailabilityServices定义了highly-available所需的各种services的get方法；ZooKeeperHaServices实现了HighAvailabilityServices接口，它通过ZooKeeperUtils的各种create方法来创建所需的service，比如ZooKeeperUtils.createLeaderRetrievalService、ZooKeeperUtils.createLeaderElectionService、ZooKeeperUtils.createSubmittedJobGraphs；像JobClient.submitJob方法就使用到了highAvailabilityServices.getJobManagerLeaderRetriever方法来获取JobManagerLeader的地址，用于提交job

doc

• JobManager High Availability (HA)