org.apache.flink.runtime.jobmaster.slotpool.LocationPreferenceSchedulingStrategy Maven / Gradle / Ivy
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* to you under the Apache License, Version 2.0 (the
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*
* http://www.apache.org/licenses/LICENSE-2.0
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package org.apache.flink.runtime.jobmaster.slotpool;
import org.apache.flink.runtime.clusterframework.types.ResourceID;
import org.apache.flink.runtime.clusterframework.types.SlotProfile;
import org.apache.flink.runtime.jobmanager.scheduler.Locality;
import org.apache.flink.runtime.jobmaster.SlotContext;
import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
import javax.annotation.Nonnull;
import javax.annotation.Nullable;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Stream;
/**
* Default {@link SchedulingStrategy} which tries to match a slot with its location preferences.
*/
public class LocationPreferenceSchedulingStrategy implements SchedulingStrategy {
private static final LocationPreferenceSchedulingStrategy INSTANCE = new LocationPreferenceSchedulingStrategy();
/**
* Calculates the candidate's locality score.
*/
private static final BiFunction LOCALITY_EVALUATION_FUNCTION = (localWeigh, hostLocalWeigh) -> localWeigh * 10 + hostLocalWeigh;
LocationPreferenceSchedulingStrategy() {}
@Nullable
@Override
public OUT findMatchWithLocality(
@Nonnull SlotProfile slotProfile,
@Nonnull Stream candidates,
@Nonnull Function contextExtractor,
@Nonnull Predicate additionalRequirementsFilter,
@Nonnull BiFunction resultProducer) {
Collection locationPreferences = slotProfile.getPreferredLocations();
// if we have no location preferences, we can only filter by the additional requirements.
if (locationPreferences.isEmpty()) {
return candidates
.filter(additionalRequirementsFilter)
.findFirst()
.map((result) -> resultProducer.apply(result, Locality.UNCONSTRAINED))
.orElse(null);
}
// we build up two indexes, one for resource id and one for host names of the preferred locations.
final Map preferredResourceIDs = new HashMap<>(locationPreferences.size());
final Map preferredFQHostNames = new HashMap<>(locationPreferences.size());
for (TaskManagerLocation locationPreference : locationPreferences) {
preferredResourceIDs.merge(locationPreference.getResourceID(), 1, Integer::sum);
preferredFQHostNames.merge(locationPreference.getFQDNHostname(), 1, Integer::sum);
}
Iterator iterator = candidates.iterator();
IN bestCandidate = null;
int bestCandidateScore = Integer.MIN_VALUE;
Locality bestCandidateLocality = null;
while (iterator.hasNext()) {
IN candidate = iterator.next();
if (additionalRequirementsFilter.test(candidate)) {
SlotContext slotContext = contextExtractor.apply(candidate);
// this gets candidate is local-weigh
Integer localWeigh = preferredResourceIDs.getOrDefault(slotContext.getTaskManagerLocation().getResourceID(), 0);
// this gets candidate is host-local-weigh
Integer hostLocalWeigh = preferredFQHostNames.getOrDefault(slotContext.getTaskManagerLocation().getFQDNHostname(), 0);
int candidateScore = LOCALITY_EVALUATION_FUNCTION.apply(localWeigh, hostLocalWeigh);
if (candidateScore > bestCandidateScore) {
bestCandidateScore = candidateScore;
bestCandidate = candidate;
bestCandidateLocality = localWeigh > 0 ? Locality.LOCAL : hostLocalWeigh > 0 ? Locality.HOST_LOCAL : Locality.NON_LOCAL;
}
}
}
// at the end of the iteration, we return the candidate with best possible locality or null.
if (bestCandidate != null) {
return resultProducer.apply(bestCandidate, bestCandidateLocality);
} else {
return null;
}
}
public static LocationPreferenceSchedulingStrategy getInstance() {
return INSTANCE;
}
}