聊聊flink的slot.idle.timeout配置

序本文主要研究一下flink的slot.idle.timeout配置JobManagerOptionsflink-release-1.7.2/flink-core/src/main/java/org/apache/flink/configuration/JobManagerOptions.java@PublicEvolvingpublic class JobManagerOptions { //…… /** * The timeout in milliseconds for a idle slot in Slot Pool. / public static final ConfigOption<Long> SLOT_IDLE_TIMEOUT = key(“slot.idle.timeout”) // default matches heartbeat.timeout so that sticky allocation is not lost on timeouts for local recovery .defaultValue(HeartbeatManagerOptions.HEARTBEAT_TIMEOUT.defaultValue()) .withDescription(“The timeout in milliseconds for a idle slot in Slot Pool.”); //……}slot.idle.timeout默认为HeartbeatManagerOptions.HEARTBEAT_TIMEOUT.defaultValue()，即50000L毫秒SlotPoolflink-release-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/jobmaster/slotpool/SlotPool.javapublic class SlotPool extends RpcEndpoint implements SlotPoolGateway, AllocatedSlotActions { /* The interval (in milliseconds) in which the SlotPool writes its slot distribution on debug level. / private static final int STATUS_LOG_INTERVAL_MS = 60_000; private final JobID jobId; private final SchedulingStrategy schedulingStrategy; private final ProviderAndOwner providerAndOwner; /* All registered TaskManagers, slots will be accepted and used only if the resource is registered. / private final HashSet<ResourceID> registeredTaskManagers; /* The book-keeping of all allocated slots. / private final AllocatedSlots allocatedSlots; /* The book-keeping of all available slots. / private final AvailableSlots availableSlots; /* All pending requests waiting for slots. / private final DualKeyMap<SlotRequestId, AllocationID, PendingRequest> pendingRequests; /* The requests that are waiting for the resource manager to be connected. / private final HashMap<SlotRequestId, PendingRequest> waitingForResourceManager; /* Timeout for external request calls (e.g. to the ResourceManager or the TaskExecutor). / private final Time rpcTimeout; /* Timeout for releasing idle slots. / private final Time idleSlotTimeout; private final Clock clock; /* Managers for the different slot sharing groups. / protected final Map<SlotSharingGroupId, SlotSharingManager> slotSharingManagers; /* the fencing token of the job manager. / private JobMasterId jobMasterId; /* The gateway to communicate with resource manager. / private ResourceManagerGateway resourceManagerGateway; private String jobManagerAddress; //…… /* * Start the slot pool to accept RPC calls. * * @param jobMasterId The necessary leader id for running the job. * @param newJobManagerAddress for the slot requests which are sent to the resource manager / public void start(JobMasterId jobMasterId, String newJobManagerAddress) throws Exception { this.jobMasterId = checkNotNull(jobMasterId); this.jobManagerAddress = checkNotNull(newJobManagerAddress); // TODO - start should not throw an exception try { super.start(); } catch (Exception e) { throw new RuntimeException(“This should never happen”, e); } scheduleRunAsync(this::checkIdleSlot, idleSlotTimeout); if (log.isDebugEnabled()) { scheduleRunAsync(this::scheduledLogStatus, STATUS_LOG_INTERVAL_MS, TimeUnit.MILLISECONDS); } } /* * Check the available slots, release the slot that is idle for a long time. / private void checkIdleSlot() { // The timestamp in SlotAndTimestamp is relative final long currentRelativeTimeMillis = clock.relativeTimeMillis(); final List<AllocatedSlot> expiredSlots = new ArrayList<>(availableSlots.size()); for (SlotAndTimestamp slotAndTimestamp : availableSlots.availableSlots.values()) { if (currentRelativeTimeMillis - slotAndTimestamp.timestamp > idleSlotTimeout.toMilliseconds()) { expiredSlots.add(slotAndTimestamp.slot); } } final FlinkException cause = new FlinkException(“Releasing idle slot.”); for (AllocatedSlot expiredSlot : expiredSlots) { final AllocationID allocationID = expiredSlot.getAllocationId(); if (availableSlots.tryRemove(allocationID) != null) { log.info(“Releasing idle slot [{}].”, allocationID); final CompletableFuture<Acknowledge> freeSlotFuture = expiredSlot.getTaskManagerGateway().freeSlot( allocationID, cause, rpcTimeout); freeSlotFuture.whenCompleteAsync( (Acknowledge ignored, Throwable throwable) -> { if (throwable != null) { if (registeredTaskManagers.contains(expiredSlot.getTaskManagerId())) { log.debug(“Releasing slot [{}] of registered TaskExecutor {} failed. " + “Trying to fulfill a different slot request.”, allocationID, expiredSlot.getTaskManagerId(), throwable); tryFulfillSlotRequestOrMakeAvailable(expiredSlot); } else { log.debug(“Releasing slot [{}] failed and owning TaskExecutor {} is no " + “longer registered. Discarding slot.”, allocationID, expiredSlot.getTaskManagerId()); } } }, getMainThreadExecutor()); } } scheduleRunAsync(this::checkIdleSlot, idleSlotTimeout); } //……}SlotPool在start方法里头，调用scheduleRunAsync方法，延时idleSlotTimeout调度执行checkIdleSlot；checkIdleSlot方法会挨个检查availableSlots的SlotAndTimestamp，判断当前时间与slotAndTimestamp.timestamp的时间差是否超过idleSlotTimeout，超过的话，则放入expiredSlots，之后对expiredSlots挨个进行availableSlots.tryRemove，然后调用TaskManagerGateway.freeSlot进行释放，之后再次调用scheduleRunAsync(this::checkIdleSlot, idleSlotTimeout)进行下一次的延时调度检测RpcEndpointflink-release-1.7.2/flink-runtime/src/main/java/org/apache/flink/runtime/rpc/RpcEndpoint.javapublic abstract class RpcEndpoint implements RpcGateway { //…… /* * Execute the runnable in the main thread of the underlying RPC endpoint, with * a delay of the given number of milliseconds. * * @param runnable Runnable to be executed * @param delay The delay after which the runnable will be executed / protected void scheduleRunAsync(Runnable runnable, Time delay) { scheduleRunAsync(runnable, delay.getSize(), delay.getUnit()); } /* * Execute the runnable in the main thread of the underlying RPC endpoint, with * a delay of the given number of milliseconds. * * @param runnable Runnable to be executed * @param delay The delay after which the runnable will be executed */ protected void scheduleRunAsync(Runnable runnable, long delay, TimeUnit unit) { rpcServer.scheduleRunAsync(runnable, unit.toMillis(delay)); } //……}RpcEndpoint提供了scheduleRunAsync，其最后调用的是rpcServer.scheduleRunAsync小结slot.idle.timeout默认为HeartbeatManagerOptions.HEARTBEAT_TIMEOUT.defaultValue()，即50000L毫秒SlotPool在start方法里头，调用scheduleRunAsync方法，延时idleSlotTimeout调度执行checkIdleSlot；checkIdleSlot方法会挨个检查availableSlots的SlotAndTimestamp，判断当前时间与slotAndTimestamp.timestamp的时间差是否超过idleSlotTimeout，超过的话，则放入expiredSlots，之后对expiredSlots挨个进行availableSlots.tryRemove，然后调用TaskManagerGateway.freeSlot进行释放，之后再次调用scheduleRunAsync(this::checkIdleSlot, idleSlotTimeout)进行下一次的延时调度检测RpcEndpoint提供了scheduleRunAsync，其最后调用的是rpcServer.scheduleRunAsyncdocslot-idle-timeout