zhuzhurk commented on a change in pull request #8851: [FLINK-12876] [runtime] Add an adapter of region failover NG for legacy scheduler URL: https://github.com/apache/flink/pull/8851#discussion_r296993735
########## File path: flink-runtime/src/main/java/org/apache/flink/runtime/executiongraph/failover/AdaptedRestartPipelinedRegionStrategyNG.java ########## @@ -0,0 +1,295 @@ +/* + * 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.executiongraph.failover; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.runtime.JobException; +import org.apache.flink.runtime.checkpoint.CheckpointException; +import org.apache.flink.runtime.checkpoint.CheckpointFailureReason; +import org.apache.flink.runtime.concurrent.FutureUtils; +import org.apache.flink.runtime.executiongraph.Execution; +import org.apache.flink.runtime.executiongraph.ExecutionGraph; +import org.apache.flink.runtime.executiongraph.ExecutionJobVertex; +import org.apache.flink.runtime.executiongraph.ExecutionVertex; +import org.apache.flink.runtime.executiongraph.GlobalModVersionMismatch; +import org.apache.flink.runtime.executiongraph.failover.adapter.DefaultFailoverTopology; +import org.apache.flink.runtime.executiongraph.failover.flip1.FailoverRegion; +import org.apache.flink.runtime.executiongraph.failover.flip1.RestartPipelinedRegionStrategy; +import org.apache.flink.runtime.jobgraph.JobStatus; +import org.apache.flink.runtime.jobgraph.JobVertexID; +import org.apache.flink.runtime.jobmanager.scheduler.CoLocationGroup; +import org.apache.flink.runtime.scheduler.ExecutionVertexVersion; +import org.apache.flink.runtime.scheduler.ExecutionVertexVersioner; +import org.apache.flink.runtime.scheduler.strategy.ExecutionVertexID; +import org.apache.flink.util.ExceptionUtils; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.CancellationException; +import java.util.concurrent.CompletableFuture; +import java.util.concurrent.CompletionException; +import java.util.stream.Collectors; + +import static org.apache.flink.util.Preconditions.checkNotNull; + +/** + * This failover strategy uses flip1.RestartPipelinedRegionStrategy to make task failover decisions. + */ +public class AdaptedRestartPipelinedRegionStrategyNG extends FailoverStrategy { + + /** The log object used for debugging. */ + private static final Logger LOG = LoggerFactory.getLogger(AdaptedRestartPipelinedRegionStrategyNG.class); + + /** The execution graph on which this FailoverStrategy works. */ + private final ExecutionGraph executionGraph; + + /** The underlying new generation region failover strategy. */ + private RestartPipelinedRegionStrategy restartPipelinedRegionStrategy; + + /** The versioner helps to maintain execution vertex versions. */ + private final ExecutionVertexVersioner executionVertexVersioner; + + public AdaptedRestartPipelinedRegionStrategyNG(final ExecutionGraph executionGraph) { + this.executionGraph = checkNotNull(executionGraph); + this.executionVertexVersioner = new ExecutionVertexVersioner(); + } + + @Override + public void onTaskFailure(final Execution taskExecution, final Throwable cause) { + // skip the failover if global restart strategy suppresses restarts + if (!executionGraph.getRestartStrategy().canRestart()) { + // delegate the failure to a global fail that will check the restart strategy and not restart + LOG.info("Fail to pass the restart strategy validation in region failover. Fallback to fail global."); + executionGraph.failGlobal(cause); + return; + } + + // skip local failover if is in global failover + if (!isLocalFailoverValid(executionGraph.getGlobalModVersion())) { + LOG.info("Skip current region failover as a global failover is ongoing."); + return; + } + + final ExecutionVertexID vertexID = getExecutionVertexID(taskExecution.getVertex()); + + final Set<ExecutionVertexID> tasksToRestart = restartPipelinedRegionStrategy.getTasksNeedingRestart(vertexID, cause); + + // restart tasks at once + restartTasks(tasksToRestart); + } + + private void restartTasks(final Set<ExecutionVertexID> verticesToRestart) { + // record current versions + final long globalModVersion = executionGraph.getGlobalModVersion(); + final Set<ExecutionVertexVersion> vertexVersions = new HashSet<>( + executionVertexVersioner.recordVertexModifications(verticesToRestart).values()); + + // cancel tasks involved in this task failure + cancelTasks(verticesToRestart) + .thenAccept( + (Object ignored) -> { + // skip local failover if is in global failover + if (!isLocalFailoverValid(globalModVersion)) { + LOG.info("Skip current region failover as a global failover is ongoing."); + return; + } + + // found out vertices which are still valid to restart. + // some vertices involved in this failover may be modified if another region + // failover happens during the cancellation stage of this failover. + // Will ignore the modified vertices as the other failover will deal with them. + final Set<ExecutionVertex> unmodifiedVertices = executionVertexVersioner + .getUnmodifiedExecutionVertices(vertexVersions) + .stream() + .map(this::getExecutionVertex) + .collect(Collectors.toSet()); + + try { + LOG.info("Finally restart {} tasks to recover from task failure.", unmodifiedVertices.size()); + + // reset tasks to CREATED state and reload state + resetTasks(unmodifiedVertices, globalModVersion); + + // re-schedule tasks + rescheduleTasks(unmodifiedVertices, globalModVersion); + } catch (GlobalModVersionMismatch e) { + // happens when a global recovery happens concurrently to the regional recovery + // just stop this local failover + } catch (Exception e) { + throw new CompletionException(e); + } + }) + .whenComplete( + (Object ignored, Throwable t) -> { + // fail globally if any error happens + if (t != null) { + LOG.info("Unexpected error happens in region failover. Fail globally.", t); + failGlobal(t); + } + }); + } + + @VisibleForTesting + protected CompletableFuture<?> cancelTasks(final Set<ExecutionVertexID> vertices) { + final List<CompletableFuture<?>> cancelFutures = vertices.stream() + .map(this::cancelExecutionVertex) + .collect(Collectors.toList()); + + return FutureUtils.combineAll(cancelFutures); + } + + private void resetTasks(final Set<ExecutionVertex> vertices, final long globalModVersion) throws Exception { + final Set<CoLocationGroup> colGroups = new HashSet<>(); + final long restartTimestamp = System.currentTimeMillis(); + + for (ExecutionVertex ev : vertices) { + CoLocationGroup cgroup = ev.getJobVertex().getCoLocationGroup(); + if (cgroup != null && !colGroups.contains(cgroup)){ + cgroup.resetConstraints(); + colGroups.add(cgroup); + } + + ev.resetForNewExecution(restartTimestamp, globalModVersion); + } + + // if there is checkpointed state, reload it into the executions + if (executionGraph.getCheckpointCoordinator() != null) { + // abort pending checkpoints to + // i) enable new checkpoint triggering without waiting for last checkpoint expired. + // ii) ensure the EXACTLY_ONCE semantics if needed. + executionGraph.getCheckpointCoordinator().abortPendingCheckpoints( + new CheckpointException(CheckpointFailureReason.JOB_FAILOVER_REGION)); + + final Map<JobVertexID, ExecutionJobVertex> involvedExecutionJobVertices = + getInvolvedExecutionJobVertices(vertices); + executionGraph.getCheckpointCoordinator().restoreLatestCheckpointedState( + involvedExecutionJobVertices, false, true); + } + } + + private void rescheduleTasks(final Set<ExecutionVertex> vertices, final long globalModVersion) throws Exception { + final CompletableFuture<Void> newSchedulingFuture; + switch (executionGraph.getScheduleMode()) { + + case LAZY_FROM_SOURCES: + newSchedulingFuture = AdaptedSchedulingUtils.scheduleLazy(vertices, executionGraph); + break; + + case EAGER: + newSchedulingFuture = AdaptedSchedulingUtils.scheduleEager(vertices, executionGraph); + break; + + default: + throw new JobException("Schedule mode is invalid."); + } + + // if no global failover is triggered in the scheduling process, + // register a failure handling callback to the scheduling + if (isLocalFailoverValid(globalModVersion)) { Review comment: This is to ensure that no global failure happens during the sync part of the schedule logic. 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