聊聊flink的KvStateRegistryGateway

序

本文主要研究一下flink的KvStateRegistryGateway

KvStateRegistryGateway

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/KvStateRegistryGateway.java

public interface KvStateRegistryGateway {

    /**
     * Notifies that queryable state has been registered.
     *
     * @param jobId    identifying the job for which to register a key value state
     * @param jobVertexId JobVertexID the KvState instance belongs to.
     * @param keyGroupRange Key group range the KvState instance belongs to.
     * @param registrationName Name under which the KvState has been registered.
     * @param kvStateId ID of the registered KvState instance.
     * @param kvStateServerAddress Server address where to find the KvState instance.
     * @return Future acknowledge if the key-value state has been registered
     */
    CompletableFuture<Acknowledge> notifyKvStateRegistered(
        final JobID jobId,
        final JobVertexID jobVertexId,
        final KeyGroupRange keyGroupRange,
        final String registrationName,
        final KvStateID kvStateId,
        final InetSocketAddress kvStateServerAddress);

    /**
     * Notifies that queryable state has been unregistered.
     *
     * @param jobId    identifying the job for which to unregister a key value state
     * @param jobVertexId JobVertexID the KvState instance belongs to.
     * @param keyGroupRange Key group index the KvState instance belongs to.
     * @param registrationName Name under which the KvState has been registered.
     * @return Future acknowledge if the key-value state has been unregistered
     */
    CompletableFuture<Acknowledge> notifyKvStateUnregistered(
        final JobID jobId,
        final JobVertexID jobVertexId,
        final KeyGroupRange keyGroupRange,
        final String registrationName);
}

• KvStateRegistryGateway接口定义了notifyKvStateRegistered、notifyKvStateUnregistered两个方法；JobMaster实现了这两个方法

JobMaster

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/JobMaster.java

public class JobMaster extends FencedRpcEndpoint<JobMasterId> implements JobMasterGateway {

    /** Default names for Flink's distributed components. */
    public static final String JOB_MANAGER_NAME = "jobmanager";
    public static final String ARCHIVE_NAME = "archive";

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

    private final JobMasterConfiguration jobMasterConfiguration;

    private final ResourceID resourceId;

    private final JobGraph jobGraph;

    private final Time rpcTimeout;

    private final HighAvailabilityServices highAvailabilityServices;

    private final BlobServer blobServer;

    private final JobManagerJobMetricGroupFactory jobMetricGroupFactory;

    private final HeartbeatManager<AccumulatorReport, Void> taskManagerHeartbeatManager;

    private final HeartbeatManager<Void, Void> resourceManagerHeartbeatManager;

    private final ScheduledExecutorService scheduledExecutorService;

    private final OnCompletionActions jobCompletionActions;

    private final FatalErrorHandler fatalErrorHandler;

    private final ClassLoader userCodeLoader;

    private final SlotPool slotPool;

    private final SlotPoolGateway slotPoolGateway;

    private final RestartStrategy restartStrategy;

    // --------- BackPressure --------

    private final BackPressureStatsTracker backPressureStatsTracker;

    // --------- ResourceManager --------

    private final LeaderRetrievalService resourceManagerLeaderRetriever;

    // --------- TaskManagers --------

    private final Map<ResourceID, Tuple2<TaskManagerLocation, TaskExecutorGateway>> registeredTaskManagers;

    // -------- Mutable fields ---------

    private ExecutionGraph executionGraph;

    @Nullable
    private JobManagerJobStatusListener jobStatusListener;

    @Nullable
    private JobManagerJobMetricGroup jobManagerJobMetricGroup;

    @Nullable
    private String lastInternalSavepoint;

    @Nullable
    private ResourceManagerAddress resourceManagerAddress;

    @Nullable
    private ResourceManagerConnection resourceManagerConnection;

    @Nullable
    private EstablishedResourceManagerConnection establishedResourceManagerConnection;

    //......

    @Override
    public CompletableFuture<Acknowledge> notifyKvStateRegistered(
            final JobID jobId,
            final JobVertexID jobVertexId,
            final KeyGroupRange keyGroupRange,
            final String registrationName,
            final KvStateID kvStateId,
            final InetSocketAddress kvStateServerAddress) {
        if (jobGraph.getJobID().equals(jobId)) {
            if (log.isDebugEnabled()) {
                log.debug("Key value state registered for job {} under name {}.",
                    jobGraph.getJobID(), registrationName);
            }

            try {
                executionGraph.getKvStateLocationRegistry().notifyKvStateRegistered(
                    jobVertexId, keyGroupRange, registrationName, kvStateId, kvStateServerAddress);

                return CompletableFuture.completedFuture(Acknowledge.get());
            } catch (Exception e) {
                log.error("Failed to notify KvStateRegistry about registration {}.", registrationName);
                return FutureUtils.completedExceptionally(e);
            }
        } else {
            if (log.isDebugEnabled()) {
                log.debug("Notification about key-value state registration for unknown job {} received.", jobId);
            }
            return FutureUtils.completedExceptionally(new FlinkJobNotFoundException(jobId));
        }
    }

    @Override
    public CompletableFuture<Acknowledge> notifyKvStateUnregistered(
            JobID jobId,
            JobVertexID jobVertexId,
            KeyGroupRange keyGroupRange,
            String registrationName) {
        if (jobGraph.getJobID().equals(jobId)) {
            if (log.isDebugEnabled()) {
                log.debug("Key value state unregistered for job {} under name {}.",
                    jobGraph.getJobID(), registrationName);
            }

            try {
                executionGraph.getKvStateLocationRegistry().notifyKvStateUnregistered(
                    jobVertexId, keyGroupRange, registrationName);

                return CompletableFuture.completedFuture(Acknowledge.get());
            } catch (Exception e) {
                log.error("Failed to notify KvStateRegistry about registration {}.", registrationName, e);
                return FutureUtils.completedExceptionally(e);
            }
        } else {
            if (log.isDebugEnabled()) {
                log.debug("Notification about key-value state deregistration for unknown job {} received.", jobId);
            }
            return FutureUtils.completedExceptionally(new FlinkJobNotFoundException(jobId));
        }
    }

    //......
}

• JobMaster的notifyKvStateRegistered方法主要是触发executionGraph.getKvStateLocationRegistry().notifyKvStateRegistered；notifyKvStateUnregistered方法主要是触发executionGraph.getKvStateLocationRegistry().notifyKvStateUnregistered

KvStateLocationRegistry

flink-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/query/KvStateLocationRegistry.java

public class KvStateLocationRegistry {

    /** JobID this coordinator belongs to. */
    private final JobID jobId;

    /** Job vertices for determining parallelism per key. */
    private final Map<JobVertexID, ExecutionJobVertex> jobVertices;

    /**
     * Location info keyed by registration name. The name needs to be unique
     * per JobID, i.e. two operators cannot register KvState with the same
     * name.
     */
    private final Map<String, KvStateLocation> lookupTable = new HashMap<>();

    /**
     * Creates the registry for the job.
     *
     * @param jobId       JobID this coordinator belongs to.
     * @param jobVertices Job vertices map of all vertices of this job.
     */
    public KvStateLocationRegistry(JobID jobId, Map<JobVertexID, ExecutionJobVertex> jobVertices) {
        this.jobId = Preconditions.checkNotNull(jobId, "JobID");
        this.jobVertices = Preconditions.checkNotNull(jobVertices, "Job vertices");
    }

    /**
     * Returns the {@link KvStateLocation} for the registered KvState instance
     * or <code>null</code> if no location information is available.
     *
     * @param registrationName Name under which the KvState instance is registered.
     * @return Location information or <code>null</code>.
     */
    public KvStateLocation getKvStateLocation(String registrationName) {
        return lookupTable.get(registrationName);
    }

    /**
     * Notifies the registry about a registered KvState instance.
     *
     * @param jobVertexId JobVertexID the KvState instance belongs to
     * @param keyGroupRange Key group range the KvState instance belongs to
     * @param registrationName Name under which the KvState has been registered
     * @param kvStateId ID of the registered KvState instance
     * @param kvStateServerAddress Server address where to find the KvState instance
     *
     * @throws IllegalArgumentException If JobVertexID does not belong to job
     * @throws IllegalArgumentException If state has been registered with same
     * name by another operator.
     * @throws IndexOutOfBoundsException If key group index is out of bounds.
     */
    public void notifyKvStateRegistered(
            JobVertexID jobVertexId,
            KeyGroupRange keyGroupRange,
            String registrationName,
            KvStateID kvStateId,
            InetSocketAddress kvStateServerAddress) {

        KvStateLocation location = lookupTable.get(registrationName);

        if (location == null) {
            // First registration for this operator, create the location info
            ExecutionJobVertex vertex = jobVertices.get(jobVertexId);

            if (vertex != null) {
                int parallelism = vertex.getMaxParallelism();
                location = new KvStateLocation(jobId, jobVertexId, parallelism, registrationName);
                lookupTable.put(registrationName, location);
            } else {
                throw new IllegalArgumentException("Unknown JobVertexID " + jobVertexId);
            }
        }

        // Duplicated name if vertex IDs don't match
        if (!location.getJobVertexId().equals(jobVertexId)) {
            IllegalStateException duplicate = new IllegalStateException(
                    "Registration name clash. KvState with name '" + registrationName +
                            "' has already been registered by another operator (" +
                            location.getJobVertexId() + ").");

            ExecutionJobVertex vertex = jobVertices.get(jobVertexId);
            if (vertex != null) {
                vertex.fail(new SuppressRestartsException(duplicate));
            }

            throw duplicate;
        }
        location.registerKvState(keyGroupRange, kvStateId, kvStateServerAddress);
    }

    /**
     * Notifies the registry about an unregistered KvState instance.
     *
     * @param jobVertexId JobVertexID the KvState instance belongs to
     * @param keyGroupRange Key group index the KvState instance belongs to
     * @param registrationName Name under which the KvState has been registered
     * @throws IllegalArgumentException If another operator registered the state instance
     * @throws IllegalArgumentException If the registration name is not known
     */
    public void notifyKvStateUnregistered(
            JobVertexID jobVertexId,
            KeyGroupRange keyGroupRange,
            String registrationName) {

        KvStateLocation location = lookupTable.get(registrationName);

        if (location != null) {
            // Duplicate name if vertex IDs don't match
            if (!location.getJobVertexId().equals(jobVertexId)) {
                throw new IllegalArgumentException("Another operator (" +
                        location.getJobVertexId() + ") registered the KvState " +
                        "under '" + registrationName + "'.");
            }

            location.unregisterKvState(keyGroupRange);

            if (location.getNumRegisteredKeyGroups() == 0) {
                lookupTable.remove(registrationName);
            }
        } else {
            throw new IllegalArgumentException("Unknown registration name '" +
                    registrationName + "'. " + "Probably registration/unregistration race.");
        }
    }

}

• KvStateLocationRegistry的构造器要求传入jobId及jobVertices；它有一个属性为lookupTable，存储了registrationName与KvStateLocation的映射关系
• notifyKvStateRegistered方法在lookupTable查找不到对应的KvStateLocation的时候会创建一个KvStateLocation并存放入lookupTable，最后调用location.registerKvState方法
• notifyKvStateUnregistere方法在lookupTable查找对应KvStateLocation的时候会触发location.unregisterKvState，然后将该KvStateLocation从lookupTable中移除

小结

• KvStateRegistryGateway接口定义了notifyKvStateRegistered、notifyKvStateUnregistered两个方法；JobMaster实现了这两个方法
• JobMaster的notifyKvStateRegistered方法主要是触发executionGraph.getKvStateLocationRegistry().notifyKvStateRegistered；notifyKvStateUnregistered方法主要是触发executionGraph.getKvStateLocationRegistry().notifyKvStateUnregistered
• KvStateLocationRegistry的构造器要求传入jobId及jobVertices；它有一个属性为lookupTable，存储了registrationName与KvStateLocation的映射关系；notifyKvStateRegistered方法在lookupTable查找不到对应的KvStateLocation的时候会创建一个KvStateLocation并存放入lookupTable，最后调用location.registerKvState方法；notifyKvStateUnregistere方法在lookupTable查找对应KvStateLocation的时候会触发location.unregisterKvState，然后将该KvStateLocation从lookupTable中移除

doc

• KvStateRegistryGateway