org.apache.flink.runtime.executiongraph.SchedulingUtils Maven / Gradle / Ivy
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package org.apache.flink.runtime.executiongraph;
import org.apache.flink.runtime.clusterframework.types.AllocationID;
import org.apache.flink.runtime.concurrent.FutureUtils;
import org.apache.flink.runtime.concurrent.FutureUtils.ConjunctFuture;
import org.apache.flink.runtime.jobgraph.JobStatus;
import org.apache.flink.runtime.jobgraph.ScheduleMode;
import org.apache.flink.runtime.jobmanager.scheduler.LocationPreferenceConstraint;
import org.apache.flink.runtime.jobmanager.scheduler.NoResourceAvailableException;
import org.apache.flink.runtime.jobmaster.slotpool.Scheduler;
import org.apache.flink.runtime.jobmaster.slotpool.SlotProvider;
import org.apache.flink.util.ExceptionUtils;
import org.apache.flink.util.FlinkException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CompletionException;
import java.util.concurrent.TimeoutException;
import static org.apache.flink.util.Preconditions.checkState;
/**
* This class contains scheduling logic for EAGER and LAZY_FROM_SOURCES.
* It is used for normal scheduling and legacy failover strategy re-scheduling.
*/
public class SchedulingUtils {
public static CompletableFuture schedule(
ScheduleMode scheduleMode,
final Iterable vertices,
final ExecutionGraph executionGraph) {
switch (scheduleMode) {
case LAZY_FROM_SOURCES:
case LAZY_FROM_SOURCES_WITH_BATCH_SLOT_REQUEST:
return scheduleLazy(vertices, executionGraph);
case EAGER:
return scheduleEager(vertices, executionGraph);
default:
throw new IllegalStateException(String.format("Schedule mode %s is invalid.", scheduleMode));
}
}
/**
* Schedule vertices lazy. That means only vertices satisfying its input constraint will be scheduled.
*
* @param vertices Topologically sorted vertices to schedule.
* @param executionGraph The graph the given vertices belong to.
*/
public static CompletableFuture scheduleLazy(
final Iterable vertices,
final ExecutionGraph executionGraph) {
executionGraph.assertRunningInJobMasterMainThread();
final SlotProviderStrategy slotProviderStrategy = executionGraph.getSlotProviderStrategy();
final Set previousAllocations = computePriorAllocationIdsIfRequiredByScheduling(
vertices, slotProviderStrategy.asSlotProvider());
final ArrayList> schedulingFutures = new ArrayList<>();
for (ExecutionVertex executionVertex : vertices) {
// only schedule vertex when its input constraint is satisfied
if (executionVertex.getJobVertex().getJobVertex().isInputVertex() ||
executionVertex.checkInputDependencyConstraints()) {
final CompletableFuture schedulingVertexFuture = executionVertex.scheduleForExecution(
slotProviderStrategy,
LocationPreferenceConstraint.ANY,
previousAllocations);
schedulingFutures.add(schedulingVertexFuture);
}
}
return FutureUtils.waitForAll(schedulingFutures);
}
/**
* Schedule vertices eagerly. That means all vertices will be scheduled at once.
*
* @param vertices Topologically sorted vertices to schedule.
* @param executionGraph The graph the given vertices belong to.
*/
public static CompletableFuture scheduleEager(
final Iterable vertices,
final ExecutionGraph executionGraph) {
executionGraph.assertRunningInJobMasterMainThread();
checkState(executionGraph.getState() == JobStatus.RUNNING, "job is not running currently");
// Important: reserve all the space we need up front.
// that way we do not have any operation that can fail between allocating the slots
// and adding them to the list. If we had a failure in between there, that would
// cause the slots to get lost
// collecting all the slots may resize and fail in that operation without slots getting lost
final ArrayList> allAllocationFutures = new ArrayList<>();
final SlotProviderStrategy slotProviderStrategy = executionGraph.getSlotProviderStrategy();
final Set allPreviousAllocationIds = Collections.unmodifiableSet(
computePriorAllocationIdsIfRequiredByScheduling(vertices, slotProviderStrategy.asSlotProvider()));
// allocate the slots (obtain all their futures)
for (ExecutionVertex ev : vertices) {
// these calls are not blocking, they only return futures
CompletableFuture allocationFuture = ev.getCurrentExecutionAttempt().allocateResourcesForExecution(
slotProviderStrategy,
LocationPreferenceConstraint.ALL,
allPreviousAllocationIds);
allAllocationFutures.add(allocationFuture);
}
// this future is complete once all slot futures are complete.
// the future fails once one slot future fails.
final ConjunctFuture> allAllocationsFuture = FutureUtils.combineAll(allAllocationFutures);
return allAllocationsFuture.thenAccept(
(Collection executionsToDeploy) -> {
for (Execution execution : executionsToDeploy) {
try {
execution.deploy();
} catch (Throwable t) {
throw new CompletionException(
new FlinkException(
String.format("Could not deploy execution %s.", execution),
t));
}
}
})
// Generate a more specific failure message for the eager scheduling
.exceptionally(
(Throwable throwable) -> {
final Throwable strippedThrowable = ExceptionUtils.stripCompletionException(throwable);
final Throwable resultThrowable;
if (strippedThrowable instanceof TimeoutException) {
int numTotal = allAllocationsFuture.getNumFuturesTotal();
int numComplete = allAllocationsFuture.getNumFuturesCompleted();
String message = "Could not allocate all requires slots within timeout of "
+ executionGraph.getAllocationTimeout() + ". Slots required: "
+ numTotal + ", slots allocated: " + numComplete
+ ", previous allocation IDs: " + allPreviousAllocationIds;
StringBuilder executionMessageBuilder = new StringBuilder();
for (int i = 0; i < allAllocationFutures.size(); i++) {
CompletableFuture executionFuture = allAllocationFutures.get(i);
try {
Execution execution = executionFuture.getNow(null);
if (execution != null) {
executionMessageBuilder.append("completed: " + execution);
} else {
executionMessageBuilder.append("incomplete: " + executionFuture);
}
} catch (CompletionException completionException) {
executionMessageBuilder.append("completed exceptionally: "
+ completionException + "/" + executionFuture);
}
if (i < allAllocationFutures.size() - 1) {
executionMessageBuilder.append(", ");
}
}
message += ", execution status: " + executionMessageBuilder.toString();
resultThrowable = new NoResourceAvailableException(message);
} else {
resultThrowable = strippedThrowable;
}
throw new CompletionException(resultThrowable);
});
}
/**
* Returns the result of {@link #computePriorAllocationIds(Iterable)},
* but only if the scheduling really requires it.
* Otherwise this method simply returns an empty set.
*/
private static Set computePriorAllocationIdsIfRequiredByScheduling(
final Iterable vertices,
final SlotProvider slotProvider) {
// This is a temporary optimization to avoid computing all previous allocations if not required
// This can go away when we progress with the implementation of the Scheduler.
if (slotProvider instanceof Scheduler &&
((Scheduler) slotProvider).requiresPreviousExecutionGraphAllocations()) {
return computePriorAllocationIds(vertices);
} else {
return Collections.emptySet();
}
}
/**
* Computes and returns a set with the prior allocation ids for given execution vertices.
*/
private static Set computePriorAllocationIds(final Iterable vertices) {
HashSet allPreviousAllocationIds = new HashSet<>();
for (ExecutionVertex executionVertex : vertices) {
AllocationID latestPriorAllocation = executionVertex.getLatestPriorAllocation();
if (latestPriorAllocation != null) {
allPreviousAllocationIds.add(latestPriorAllocation);
}
}
return allPreviousAllocationIds;
}
}