opendaylight/md-sal/eos-dom-akka/src/main/java/org/opendaylight/controller/eos/akka/owner/supervisor/OwnerSupervisor.java

   1 /*
   2  * Copyright (c) 2021 PANTHEON.tech, s.r.o. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.controller.eos.akka.owner.supervisor;
   9
  10 import akka.actor.typed.ActorRef;
  11 import akka.actor.typed.Behavior;
  12 import akka.actor.typed.javadsl.AbstractBehavior;
  13 import akka.actor.typed.javadsl.ActorContext;
  14 import akka.actor.typed.javadsl.Behaviors;
  15 import akka.actor.typed.javadsl.Receive;
  16 import akka.cluster.ClusterEvent;
  17 import akka.cluster.Member;
  18 import akka.cluster.ddata.LWWRegister;
  19 import akka.cluster.ddata.LWWRegisterKey;
  20 import akka.cluster.ddata.ORMap;
  21 import akka.cluster.ddata.ORSet;
  22 import akka.cluster.ddata.SelfUniqueAddress;
  23 import akka.cluster.ddata.typed.javadsl.DistributedData;
  24 import akka.cluster.ddata.typed.javadsl.Replicator;
  25 import akka.cluster.ddata.typed.javadsl.ReplicatorMessageAdapter;
  26 import akka.cluster.typed.Cluster;
  27 import akka.cluster.typed.Subscribe;
  28 import com.google.common.collect.HashMultimap;
  29 import com.google.common.collect.ImmutableList;
  30 import com.google.common.collect.ImmutableSet;
  31 import com.google.common.collect.Multimap;
  32 import com.google.common.collect.Sets;
  33 import java.time.Duration;
  34 import java.util.ArrayList;
  35 import java.util.Collection;
  36 import java.util.Collections;
  37 import java.util.HashSet;
  38 import java.util.List;
  39 import java.util.Map;
  40 import java.util.Set;
  41 import java.util.function.BiPredicate;
  42 import java.util.stream.Collectors;
  43 import org.opendaylight.controller.eos.akka.owner.supervisor.command.CandidatesChanged;
  44 import org.opendaylight.controller.eos.akka.owner.supervisor.command.DataCenterDeactivated;
  45 import org.opendaylight.controller.eos.akka.owner.supervisor.command.DeactivateDataCenter;
  46 import org.opendaylight.controller.eos.akka.owner.supervisor.command.MemberDownEvent;
  47 import org.opendaylight.controller.eos.akka.owner.supervisor.command.MemberReachableEvent;
  48 import org.opendaylight.controller.eos.akka.owner.supervisor.command.MemberUnreachableEvent;
  49 import org.opendaylight.controller.eos.akka.owner.supervisor.command.MemberUpEvent;
  50 import org.opendaylight.controller.eos.akka.owner.supervisor.command.OwnerChanged;
  51 import org.opendaylight.controller.eos.akka.owner.supervisor.command.OwnerSupervisorCommand;
  52 import org.opendaylight.controller.eos.akka.registry.candidate.CandidateRegistry;
  53 import org.opendaylight.mdsal.eos.dom.api.DOMEntity;
  54 import org.slf4j.Logger;
  55 import org.slf4j.LoggerFactory;
  56 import scala.collection.JavaConverters;
  57
  58 /**
  59  * Responsible for tracking candidates and assigning ownership of entities. This behavior is subscribed to the candidate
  60  * registry in distributed-data and picks entity owners based on the current cluster state and registered candidates.
  61  * On cluster up/down etc. events the owners are reassigned if possible.
  62  */
  63 public final class OwnerSupervisor extends AbstractBehavior<OwnerSupervisorCommand> {
  64
  65     private static final Logger LOG = LoggerFactory.getLogger(OwnerSupervisor.class);
  66     private static final String DATACENTER_PREFIX = "dc-";
  67
  68     private final ReplicatorMessageAdapter<OwnerSupervisorCommand, LWWRegister<String>> ownerReplicator;
  69
  70     // Our own clock implementation so we do not have to rely on synchronized clocks. This basically functions as an
  71     // increasing counter which is fine for our needs as we only ever have a single writer since t supervisor is
  72     // running in a cluster-singleton
  73     private final LWWRegister.Clock<String> clock = (currentTimestamp, value) -> currentTimestamp + 1;
  74
  75     private final Cluster cluster;
  76     private final SelfUniqueAddress node;
  77     private final String dataCenter;
  78
  79     private final Set<String> activeMembers;
  80
  81     // currently registered candidates
  82     private final Map<DOMEntity, Set<String>> currentCandidates;
  83     // current owners
  84     private final Map<DOMEntity, String> currentOwners;
  85     // reverse lookup of owner to entity
  86     private final Multimap<String, DOMEntity> ownerToEntity = HashMultimap.create();
  87
  88     // only reassign owner for those entities that lost this candidate or is not reachable
  89     private final BiPredicate<DOMEntity, String> reassignPredicate = (entity, candidate) ->
  90             !isActiveCandidate(candidate) || !isCandidateFor(entity, candidate);
  91
  92     private OwnerSupervisor(final ActorContext<OwnerSupervisorCommand> context,
  93                             final Map<DOMEntity, Set<String>> currentCandidates,
  94                             final Map<DOMEntity, String> currentOwners) {
  95         super(context);
  96
  97         final DistributedData distributedData = DistributedData.get(context.getSystem());
  98         final ActorRef<Replicator.Command> replicator = distributedData.replicator();
  99
 100         cluster = Cluster.get(context.getSystem());
 101         ownerReplicator = new ReplicatorMessageAdapter<>(context, replicator, Duration.ofSeconds(5));
 102         dataCenter = extractDatacenterRole(cluster.selfMember());
 103
 104         node = distributedData.selfUniqueAddress();
 105         activeMembers = getActiveMembers();
 106
 107         this.currentCandidates = currentCandidates;
 108         this.currentOwners = currentOwners;
 109
 110         for (final Map.Entry<DOMEntity, String> entry : currentOwners.entrySet()) {
 111             ownerToEntity.put(entry.getValue(), entry.getKey());
 112         }
 113
 114         // check whether we have any unreachable/missing owners
 115         reassignUnreachableOwners();
 116         assignMissingOwners();
 117
 118         final ActorRef<ClusterEvent.MemberEvent> memberEventAdapter =
 119                 context.messageAdapter(ClusterEvent.MemberEvent.class, event -> {
 120                     if (event instanceof ClusterEvent.MemberUp) {
 121                         return new MemberUpEvent(event.member().address(), event.member().getRoles());
 122                     } else {
 123                         return new MemberDownEvent(event.member().address(), event.member().getRoles());
 124                     }
 125                 });
 126         cluster.subscriptions().tell(Subscribe.create(memberEventAdapter, ClusterEvent.MemberEvent.class));
 127
 128         final ActorRef<ClusterEvent.ReachabilityEvent> reachabilityEventAdapter =
 129                 context.messageAdapter(ClusterEvent.ReachabilityEvent.class, event -> {
 130                     if (event instanceof ClusterEvent.ReachableMember) {
 131                         return new MemberReachableEvent(event.member().address(), event.member().getRoles());
 132                     } else {
 133                         return new MemberUnreachableEvent(event.member().address(), event.member().getRoles());
 134                     }
 135                 });
 136         cluster.subscriptions().tell(Subscribe.create(reachabilityEventAdapter, ClusterEvent.ReachabilityEvent.class));
 137
 138         new ReplicatorMessageAdapter<OwnerSupervisorCommand, ORMap<DOMEntity, ORSet<String>>>(context, replicator,
 139             Duration.ofSeconds(5)).subscribe(CandidateRegistry.KEY, CandidatesChanged::new);
 140
 141         LOG.debug("Owner Supervisor started");
 142     }
 143
 144     public static Behavior<OwnerSupervisorCommand> create(final Map<DOMEntity, Set<String>> currentCandidates,
 145                                                           final Map<DOMEntity, String> currentOwners) {
 146         return Behaviors.setup(ctx -> new OwnerSupervisor(ctx, currentCandidates, currentOwners));
 147     }
 148
 149     @Override
 150     public Receive<OwnerSupervisorCommand> createReceive() {
 151         return newReceiveBuilder()
 152                 .onMessage(CandidatesChanged.class, this::onCandidatesChanged)
 153                 .onMessage(DeactivateDataCenter.class, this::onDeactivateDatacenter)
 154                 .onMessage(MemberUpEvent.class, this::onPeerUp)
 155                 .onMessage(MemberDownEvent.class, this::onPeerDown)
 156                 .onMessage(MemberReachableEvent.class, this::onPeerReachable)
 157                 .onMessage(MemberUnreachableEvent.class, this::onPeerUnreachable)
 158                 .build();
 159     }
 160
 161     private Behavior<OwnerSupervisorCommand> onDeactivateDatacenter(final DeactivateDataCenter command) {
 162         LOG.debug("Deactivating Owner Supervisor on {}", cluster.selfMember());
 163         command.getReplyTo().tell(DataCenterDeactivated.INSTANCE);
 164         return IdleSupervisor.create();
 165     }
 166
 167     private void reassignUnreachableOwners() {
 168         final Set<String> ownersToReassign = new HashSet<>();
 169         for (final String owner : ownerToEntity.keys()) {
 170             if (!activeMembers.contains(owner)) {
 171                 ownersToReassign.add(owner);
 172             }
 173         }
 174
 175         for (final String owner : ownersToReassign) {
 176             reassignCandidatesFor(owner, ImmutableList.copyOf(ownerToEntity.get(owner)), reassignPredicate);
 177         }
 178     }
 179
 180     private void assignMissingOwners() {
 181         for (final Map.Entry<DOMEntity, Set<String>> entry : currentCandidates.entrySet()) {
 182             if (!currentOwners.containsKey(entry.getKey())) {
 183                 assignOwnerFor(entry.getKey());
 184             }
 185         }
 186     }
 187
 188     private Behavior<OwnerSupervisorCommand> onCandidatesChanged(final CandidatesChanged message) {
 189         LOG.debug("onCandidatesChanged {}", message.getResponse());
 190         if (message.getResponse() instanceof Replicator.Changed) {
 191             final Replicator.Changed<ORMap<DOMEntity, ORSet<String>>> changed =
 192                     (Replicator.Changed<ORMap<DOMEntity, ORSet<String>>>) message.getResponse();
 193             processCandidateChanges(changed.get(CandidateRegistry.KEY));
 194         }
 195         return this;
 196     }
 197
 198     private void processCandidateChanges(final ORMap<DOMEntity, ORSet<String>> candidates) {
 199         final Map<DOMEntity, ORSet<String>> entries = candidates.getEntries();
 200         for (final Map.Entry<DOMEntity, ORSet<String>> entry : entries.entrySet()) {
 201             processCandidatesFor(entry.getKey(), entry.getValue());
 202         }
 203     }
 204
 205     private void processCandidatesFor(final DOMEntity entity, final ORSet<String> receivedCandidates) {
 206         LOG.debug("Processing candidates for : {}, new value: {}", entity, receivedCandidates.elements());
 207
 208         final Set<String> candidates = JavaConverters.asJava(receivedCandidates.elements());
 209         // only insert candidates if there are any to insert, otherwise we would generate unnecessary notification with
 210         // no owner
 211         if (!currentCandidates.containsKey(entity) && !candidates.isEmpty()) {
 212             LOG.debug("Candidates missing for entity: {} adding all candidates", entity);
 213             currentCandidates.put(entity, new HashSet<>(candidates));
 214
 215             LOG.debug("Current state for {} : {}", entity, currentCandidates.get(entity).toString());
 216             assignOwnerFor(entity);
 217
 218             return;
 219         }
 220
 221         final Set<String> currentlyPresent = currentCandidates.getOrDefault(entity, Collections.emptySet());
 222         final Set<String> difference = ImmutableSet.copyOf(Sets.symmetricDifference(currentlyPresent, candidates));
 223
 224         LOG.debug("currently present candidates: {}", currentlyPresent);
 225         LOG.debug("difference: {}", difference);
 226
 227         final List<String> ownersToReassign = new ArrayList<>();
 228
 229         // first add/remove candidates from entities
 230         for (final String toCheck : difference) {
 231             if (!currentlyPresent.contains(toCheck)) {
 232                 // add new candidate
 233                 LOG.debug("Adding new candidate for entity: {} : {}", entity, toCheck);
 234                 currentCandidates.get(entity).add(toCheck);
 235
 236                 if (!currentOwners.containsKey(entity)) {
 237                     // might as well assign right away when we don't have an owner
 238                     assignOwnerFor(entity);
 239                 }
 240
 241                 LOG.debug("Current state for entity: {} : {}", entity, currentCandidates.get(entity).toString());
 242                 continue;
 243             }
 244
 245             if (!candidates.contains(toCheck)) {
 246                 // remove candidate
 247                 LOG.debug("Removing candidate from entity: {} - {}", entity, toCheck);
 248                 currentCandidates.get(entity).remove(toCheck);
 249                 if (ownerToEntity.containsKey(toCheck)) {
 250                     ownersToReassign.add(toCheck);
 251                 }
 252             }
 253         }
 254
 255         // then reassign those that need new owners
 256         for (final String toReassign : ownersToReassign) {
 257             reassignCandidatesFor(toReassign, ImmutableList.copyOf(ownerToEntity.get(toReassign)),
 258                     reassignPredicate);
 259         }
 260
 261         if (currentCandidates.get(entity) == null) {
 262             LOG.debug("Last candidate removed for {}", entity);
 263         } else {
 264             LOG.debug("Current state for entity: {} : {}", entity, currentCandidates.get(entity).toString());
 265         }
 266     }
 267
 268     private void reassignCandidatesFor(final String oldOwner, final Collection<DOMEntity> entities,
 269                                        final BiPredicate<DOMEntity, String> predicate) {
 270         LOG.debug("Reassigning owners for {}", entities);
 271         for (final DOMEntity entity : entities) {
 272
 273
 274             if (predicate.test(entity, oldOwner)) {
 275                 ownerToEntity.remove(oldOwner, entity);
 276                 assignOwnerFor(entity);
 277             }
 278         }
 279     }
 280
 281     private boolean isActiveCandidate(final String candidate) {
 282         return activeMembers.contains(candidate);
 283     }
 284
 285     private boolean isCandidateFor(final DOMEntity entity, final String candidate) {
 286         return currentCandidates.getOrDefault(entity, Collections.emptySet()).contains(candidate);
 287     }
 288
 289     private void assignOwnerFor(final DOMEntity entity) {
 290         final Set<String> candidatesForEntity = currentCandidates.get(entity);
 291         if (candidatesForEntity.isEmpty()) {
 292             LOG.debug("No candidates present for entity: {}", entity);
 293             removeOwner(entity);
 294             return;
 295         }
 296
 297         String pickedCandidate = null;
 298         for (final String candidate : candidatesForEntity) {
 299             if (activeMembers.contains(candidate)) {
 300                 pickedCandidate = candidate;
 301                 break;
 302             }
 303         }
 304         if (pickedCandidate == null) {
 305             LOG.debug("No candidate is reachable for {}, activeMembers: {}, currentCandidates: {}",
 306                     entity, activeMembers, currentCandidates.get(entity));
 307             // no candidate is reachable so only remove owner if necessary
 308             removeOwner(entity);
 309             return;
 310         }
 311         ownerToEntity.put(pickedCandidate, entity);
 312
 313         LOG.debug("Entity {} new owner: {}", entity, pickedCandidate);
 314         currentOwners.put(entity, pickedCandidate);
 315         writeNewOwner(entity, pickedCandidate);
 316     }
 317
 318     private void removeOwner(final DOMEntity entity) {
 319         if (currentOwners.containsKey(entity)) {
 320             // assign empty owner to dd, as we cannot delete data for a key since that would prevent
 321             // writes for the same key
 322             currentOwners.remove(entity);
 323
 324             writeNewOwner(entity, "");
 325         }
 326     }
 327
 328     private void writeNewOwner(final DOMEntity entity, final String candidate) {
 329         ownerReplicator.askUpdate(
 330                 askReplyTo -> new Replicator.Update<>(
 331                         new LWWRegisterKey<>(entity.toString()),
 332                         new LWWRegister<>(node.uniqueAddress(), candidate, 0),
 333                         Replicator.writeLocal(),
 334                         askReplyTo,
 335                         register -> register.withValue(node, candidate, clock)),
 336                 OwnerChanged::new);
 337     }
 338
 339     private Behavior<OwnerSupervisorCommand> onPeerUp(final MemberUpEvent event) {
 340         LOG.debug("Received MemberUp : {}", event);
 341
 342         handleReachableEvent(event.getRoles());
 343         return this;
 344     }
 345
 346     private Behavior<OwnerSupervisorCommand> onPeerReachable(final MemberReachableEvent event) {
 347         LOG.debug("Received MemberReachable : {}", event);
 348
 349         handleReachableEvent(event.getRoles());
 350         return this;
 351     }
 352
 353     private void handleReachableEvent(final Set<String> roles) {
 354         if (roles.contains(dataCenter)) {
 355             activeMembers.add(extractRole(roles));
 356             assignMissingOwners();
 357         } else {
 358             LOG.debug("Received reachable event from a foreign datacenter, Ignoring... Roles: {}", roles);
 359         }
 360     }
 361
 362     private Behavior<OwnerSupervisorCommand> onPeerDown(final MemberDownEvent event) {
 363         LOG.debug("Received MemberDown : {}", event);
 364
 365         handleUnreachableEvent(event.getRoles());
 366         return this;
 367     }
 368
 369     private Behavior<OwnerSupervisorCommand> onPeerUnreachable(final MemberUnreachableEvent event) {
 370         LOG.debug("Received MemberUnreachable : {}", event);
 371
 372         handleUnreachableEvent(event.getRoles());
 373         return this;
 374     }
 375
 376     private void handleUnreachableEvent(final Set<String> roles) {
 377         if (roles.contains(dataCenter)) {
 378             activeMembers.remove(extractRole(roles));
 379             reassignUnreachableOwners();
 380         } else {
 381             LOG.debug("Received unreachable event from a foreign datacenter, Ignoring... Roles: {}", roles);
 382         }
 383     }
 384
 385     private Set<String> getActiveMembers() {
 386         final Set<String> members = new HashSet<>();
 387         cluster.state().getMembers().forEach(member -> members.add(extractRole(member)));
 388         // filter out unreachable
 389         members.removeAll(cluster.state().getUnreachable().stream()
 390                 .map(OwnerSupervisor::extractRole)
 391                 .collect(Collectors.toSet()));
 392
 393         // filter out members not from our datacenter
 394         cluster.state().getMembers().forEach(member -> {
 395             if (!member.roles().contains(dataCenter)) {
 396                 members.remove(extractRole(member));
 397             }
 398         });
 399
 400         return members;
 401     }
 402
 403     private static String extractRole(final Member member) {
 404         return extractRole(member.getRoles());
 405     }
 406
 407     private static String extractRole(final Set<String> roles) {
 408         return roles.stream().filter(role -> !role.startsWith(DATACENTER_PREFIX))
 409                 .findFirst().orElseThrow(() -> new IllegalArgumentException("No valid role found."));
 410     }
 411
 412     private String extractDatacenterRole(final Member member) {
 413         return member.getRoles().stream().filter(role -> role.startsWith(DATACENTER_PREFIX))
 414                 .findFirst().orElseThrow(() -> new IllegalArgumentException("No valid role found."));
 415     }
 416 }