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