org.apache.flink.runtime.jobmaster.slotpool.LocationPreferenceSlotSelectionStrategy 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.ResourceProfile;
import org.apache.flink.runtime.clusterframework.types.SlotProfile;
import org.apache.flink.runtime.jobmanager.scheduler.Locality;
import org.apache.flink.runtime.taskmanager.TaskManagerLocation;
import javax.annotation.Nonnull;
import java.util.Collection;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.function.BiFunction;
/**
* This class implements a {@link SlotSelectionStrategy} that is based on location preference hints.
*/
public enum LocationPreferenceSlotSelectionStrategy implements SlotSelectionStrategy {
INSTANCE;
/**
* Calculates the candidate's locality score.
*/
private static final BiFunction LOCALITY_EVALUATION_FUNCTION =
(localWeigh, hostLocalWeigh) -> localWeigh * 10 + hostLocalWeigh;
@Override
public Optional selectBestSlotForProfile(
@Nonnull Collection availableSlots,
@Nonnull SlotProfile slotProfile) {
Collection locationPreferences = slotProfile.getPreferredLocations();
if (availableSlots.isEmpty()) {
return Optional.empty();
}
final ResourceProfile resourceProfile = slotProfile.getResourceProfile();
// if we have no location preferences, we can only filter by the additional requirements.
return locationPreferences.isEmpty() ?
selectWithoutLocationPreference(availableSlots, resourceProfile) :
selectWitLocationPreference(availableSlots, locationPreferences, resourceProfile);
}
@Nonnull
private Optional selectWithoutLocationPreference(
@Nonnull Collection availableSlots,
@Nonnull ResourceProfile resourceProfile) {
for (SlotInfoAndResources candidate : availableSlots) {
if (candidate.getRemainingResources().isMatching(resourceProfile)) {
return Optional.of(SlotInfoAndLocality.of(candidate.getSlotInfo(), Locality.UNCONSTRAINED));
}
}
return Optional.empty();
}
@Nonnull
private Optional selectWitLocationPreference(
@Nonnull Collection availableSlots,
@Nonnull Collection locationPreferences,
@Nonnull ResourceProfile resourceProfile) {
// 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);
}
SlotInfoAndResources bestCandidate = null;
Locality bestCandidateLocality = Locality.UNKNOWN;
int bestCandidateScore = Integer.MIN_VALUE;
for (SlotInfoAndResources candidate : availableSlots) {
if (candidate.getRemainingResources().isMatching(resourceProfile)) {
// this gets candidate is local-weigh
Integer localWeigh = preferredResourceIDs.getOrDefault(
candidate.getSlotInfo().getTaskManagerLocation().getResourceID(), 0);
// this gets candidate is host-local-weigh
Integer hostLocalWeigh = preferredFQHostNames.getOrDefault(
candidate.getSlotInfo().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.
return bestCandidate != null ?
Optional.of(SlotInfoAndLocality.of(bestCandidate.getSlotInfo(), bestCandidateLocality)) :
Optional.empty();
}
}