import com.google.common.base.Preconditions;
import java.util.ArrayDeque;
import java.util.ArrayList;
+import java.util.Collection;
+import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Queue;
import java.util.UUID;
import javax.annotation.Nullable;
-import org.opendaylight.controller.cluster.raft.RaftActorLeadershipTransferCohort.OnComplete;
-import org.opendaylight.controller.cluster.raft.ServerConfigurationPayload.ServerInfo;
import org.opendaylight.controller.cluster.raft.base.messages.ApplyState;
import org.opendaylight.controller.cluster.raft.base.messages.SnapshotComplete;
+import org.opendaylight.controller.cluster.raft.base.messages.TimeoutNow;
import org.opendaylight.controller.cluster.raft.behaviors.AbstractLeader;
import org.opendaylight.controller.cluster.raft.messages.AddServer;
import org.opendaylight.controller.cluster.raft.messages.AddServerReply;
import org.opendaylight.controller.cluster.raft.messages.ServerChangeStatus;
import org.opendaylight.controller.cluster.raft.messages.ServerRemoved;
import org.opendaylight.controller.cluster.raft.messages.UnInitializedFollowerSnapshotReply;
+import org.opendaylight.controller.cluster.raft.persisted.ServerConfigurationPayload;
+import org.opendaylight.controller.cluster.raft.persisted.ServerInfo;
import org.opendaylight.controller.cluster.raft.protobuff.client.messages.Payload;
+import org.opendaylight.yangtools.concepts.Identifier;
+import org.opendaylight.yangtools.util.AbstractUUIDIdentifier;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
+import scala.concurrent.duration.FiniteDuration;
/**
* Handles server configuration related messages for a RaftActor.
class RaftActorServerConfigurationSupport {
private static final Logger LOG = LoggerFactory.getLogger(RaftActorServerConfigurationSupport.class);
+ @SuppressWarnings("checkstyle:MemberName")
private final OperationState IDLE = new Idle();
private final RaftActor raftActor;
private OperationState currentOperationState = IDLE;
- RaftActorServerConfigurationSupport(RaftActor raftActor) {
+ RaftActorServerConfigurationSupport(final RaftActor raftActor) {
this.raftActor = raftActor;
this.raftContext = raftActor.getRaftActorContext();
}
- boolean handleMessage(Object message, ActorRef sender) {
- if(message instanceof AddServer) {
+ boolean handleMessage(final Object message, final ActorRef sender) {
+ if (message instanceof AddServer) {
onAddServer((AddServer) message, sender);
return true;
- } else if(message instanceof RemoveServer) {
+ } else if (message instanceof RemoveServer) {
onRemoveServer((RemoveServer) message, sender);
return true;
- } else if(message instanceof ChangeServersVotingStatus) {
+ } else if (message instanceof ChangeServersVotingStatus) {
onChangeServersVotingStatus((ChangeServersVotingStatus) message, sender);
return true;
} else if (message instanceof ServerOperationTimeout) {
} else if (message instanceof UnInitializedFollowerSnapshotReply) {
currentOperationState.onUnInitializedFollowerSnapshotReply((UnInitializedFollowerSnapshotReply) message);
return true;
- } else if(message instanceof ApplyState) {
+ } else if (message instanceof ApplyState) {
return onApplyState((ApplyState) message);
- } else if(message instanceof SnapshotComplete) {
+ } else if (message instanceof SnapshotComplete) {
currentOperationState.onSnapshotComplete();
return false;
} else {
}
}
- private void onChangeServersVotingStatus(ChangeServersVotingStatus message, ActorRef sender) {
+ void onNewLeader(final String leaderId) {
+ currentOperationState.onNewLeader(leaderId);
+ }
+
+ private void onChangeServersVotingStatus(final ChangeServersVotingStatus message, final ActorRef sender) {
LOG.debug("{}: onChangeServersVotingStatus: {}, state: {}", raftContext.getId(), message,
currentOperationState);
- onNewOperation(new ChangeServersVotingStatusContext(message, sender));
+ // The following check is a special case. Normally we fail an operation if there's no leader.
+ // Consider a scenario where one has 2 geographically-separated 3-node clusters, one a primary and
+ // the other a backup such that if the primary cluster is lost, the backup can take over. In this
+ // scenario, we have a logical 6-node cluster where the primary sub-cluster is configured as voting
+ // and the backup sub-cluster as non-voting such that the primary cluster can make progress without
+ // consensus from the backup cluster while still replicating to the backup. On fail-over to the backup,
+ // a request would be sent to a member of the backup cluster to flip the voting states, ie make the
+ // backup sub-cluster voting and the lost primary non-voting. However since the primary majority
+ // cluster is lost, there would be no leader to apply, persist and replicate the server config change.
+ // Therefore, if the local server is currently non-voting and is to be changed to voting and there is
+ // no current leader, we will try to elect a leader using the new server config in order to replicate
+ // the change and progress.
+ boolean localServerChangingToVoting = Boolean.TRUE.equals(message
+ .getServerVotingStatusMap().get(raftActor.getRaftActorContext().getId()));
+ boolean hasNoLeader = raftActor.getLeaderId() == null;
+ if (localServerChangingToVoting && !raftContext.isVotingMember() && hasNoLeader) {
+ currentOperationState.onNewOperation(new ChangeServersVotingStatusContext(message, sender, true));
+ } else {
+ onNewOperation(new ChangeServersVotingStatusContext(message, sender, false));
+ }
}
- private void onRemoveServer(RemoveServer removeServer, ActorRef sender) {
+ private void onRemoveServer(final RemoveServer removeServer, final ActorRef sender) {
LOG.debug("{}: onRemoveServer: {}, state: {}", raftContext.getId(), removeServer, currentOperationState);
- boolean isSelf = removeServer.getServerId().equals(raftActor.getId());
- if(isSelf && !raftContext.hasFollowers()) {
+ boolean isSelf = removeServer.getServerId().equals(raftContext.getId());
+ if (isSelf && !raftContext.hasFollowers()) {
sender.tell(new RemoveServerReply(ServerChangeStatus.NOT_SUPPORTED, raftActor.getLeaderId()),
raftActor.getSelf());
- } else if(!isSelf && !raftContext.getPeerIds().contains(removeServer.getServerId())) {
+ } else if (!isSelf && !raftContext.getPeerIds().contains(removeServer.getServerId())) {
sender.tell(new RemoveServerReply(ServerChangeStatus.DOES_NOT_EXIST, raftActor.getLeaderId()),
raftActor.getSelf());
} else {
}
}
- private boolean onApplyState(ApplyState applyState) {
+ private boolean onApplyState(final ApplyState applyState) {
Payload data = applyState.getReplicatedLogEntry().getData();
- if(data instanceof ServerConfigurationPayload) {
+ if (data instanceof ServerConfigurationPayload) {
currentOperationState.onApplyState(applyState);
return true;
}
}
/**
- * The algorithm for AddServer is as follows:
+ * Add a server. The algorithm for AddServer is as follows:
* <ul>
* <li>Add the new server as a peer.</li>
* <li>Add the new follower to the leader.</li>
* <li>Respond to caller with TIMEOUT.</li>
* </ul>
*/
- private void onAddServer(AddServer addServer, ActorRef sender) {
+ private void onAddServer(final AddServer addServer, final ActorRef sender) {
LOG.debug("{}: onAddServer: {}, state: {}", raftContext.getId(), addServer, currentOperationState);
onNewOperation(new AddServerContext(addServer, sender));
}
- private void onNewOperation(ServerOperationContext<?> operationContext) {
+ private void onNewOperation(final ServerOperationContext<?> operationContext) {
if (raftActor.isLeader()) {
currentOperationState.onNewOperation(operationContext);
} else {
ActorSelection leader = raftActor.getLeader();
if (leader != null) {
LOG.debug("{}: Not leader - forwarding to leader {}", raftContext.getId(), leader);
- leader.forward(operationContext.getOperation(), raftActor.getContext());
+ leader.tell(operationContext.getOperation(), operationContext.getClientRequestor());
} else {
LOG.debug("{}: No leader - returning NO_LEADER reply", raftContext.getId());
operationContext.getClientRequestor().tell(operationContext.newReply(
* Abstract base class for a server operation FSM state. Handles common behavior for all states.
*/
private abstract class OperationState {
- void onNewOperation(ServerOperationContext<?> operationContext) {
+ void onNewOperation(final ServerOperationContext<?> operationContext) {
// We're currently processing another operation so queue it to be processed later.
LOG.debug("{}: Server operation already in progress - queueing {}", raftContext.getId(),
pendingOperationsQueue.add(operationContext);
}
- void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ void onServerOperationTimeout(final ServerOperationTimeout timeout) {
LOG.debug("onServerOperationTimeout should not be called in state {}", this);
}
- void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply) {
+ void onUnInitializedFollowerSnapshotReply(final UnInitializedFollowerSnapshotReply reply) {
LOG.debug("onUnInitializedFollowerSnapshotReply was called in state {}", this);
}
- void onApplyState(ApplyState applyState) {
+ void onApplyState(final ApplyState applyState) {
LOG.debug("onApplyState was called in state {}", this);
}
}
- protected void persistNewServerConfiguration(ServerOperationContext<?> operationContext){
+ void onNewLeader(final String newLeader) {
+ }
+
+ protected void persistNewServerConfiguration(final ServerOperationContext<?> operationContext) {
raftContext.setDynamicServerConfigurationInUse();
ServerConfigurationPayload payload = raftContext.getPeerServerInfo(
operationContext.includeSelfInNewConfiguration(raftActor));
LOG.debug("{}: New server configuration : {}", raftContext.getId(), payload.getServerConfig());
- raftActor.persistData(operationContext.getClientRequestor(), operationContext.getContextId(), payload);
+ raftActor.persistData(operationContext.getClientRequestor(), operationContext.getContextId(),
+ payload, false);
currentOperationState = new Persisting(operationContext, newTimer(new ServerOperationTimeout(
operationContext.getLoggingContext())));
sendReply(operationContext, ServerChangeStatus.OK);
}
- protected void operationComplete(ServerOperationContext<?> operationContext, @Nullable ServerChangeStatus replyStatus) {
- if(replyStatus != null) {
+ protected void operationComplete(final ServerOperationContext<?> operationContext,
+ @Nullable final ServerChangeStatus replyStatus) {
+ if (replyStatus != null) {
sendReply(operationContext, replyStatus);
}
operationContext.operationComplete(raftActor, replyStatus == null || replyStatus == ServerChangeStatus.OK);
+ changeToIdleState();
+ }
+
+ protected void changeToIdleState() {
currentOperationState = IDLE;
ServerOperationContext<?> nextOperation = pendingOperationsQueue.poll();
- if(nextOperation != null) {
+ if (nextOperation != null) {
RaftActorServerConfigurationSupport.this.onNewOperation(nextOperation);
}
}
- protected void sendReply(ServerOperationContext<?> operationContext, ServerChangeStatus status) {
- LOG.debug("{}: Returning {} for operation {}", raftContext.getId(), status, operationContext.getOperation());
+ protected void sendReply(final ServerOperationContext<?> operationContext, final ServerChangeStatus status) {
+ LOG.debug("{}: Returning {} for operation {}", raftContext.getId(), status,
+ operationContext.getOperation());
operationContext.getClientRequestor().tell(operationContext.newReply(status, raftActor.getLeaderId()),
raftActor.self());
}
- Cancellable newTimer(Object message) {
+ Cancellable newTimer(final Object message) {
+ return newTimer(raftContext.getConfigParams().getElectionTimeOutInterval().$times(2), message);
+ }
+
+ Cancellable newTimer(final FiniteDuration timeout, final Object message) {
return raftContext.getActorSystem().scheduler().scheduleOnce(
- raftContext.getConfigParams().getElectionTimeOutInterval().$times(2), raftContext.getActor(), message,
+ timeout, raftContext.getActor(), message,
raftContext.getActorSystem().dispatcher(), raftContext.getActor());
}
*/
private final class Idle extends OperationState {
@Override
- public void onNewOperation(ServerOperationContext<?> operationContext) {
+ public void onNewOperation(final ServerOperationContext<?> operationContext) {
operationContext.newInitialOperationState(RaftActorServerConfigurationSupport.this).initiate();
}
@Override
- public void onApplyState(ApplyState applyState) {
+ public void onApplyState(final ApplyState applyState) {
// Noop - we override b/c ApplyState is called normally for followers in the idle state.
}
}
private final Cancellable timer;
private boolean timedOut = false;
- Persisting(ServerOperationContext<?> operationContext, Cancellable timer) {
+ Persisting(final ServerOperationContext<?> operationContext, final Cancellable timer) {
this.operationContext = operationContext;
this.timer = timer;
}
@Override
- public void onApplyState(ApplyState applyState) {
+ public void onApplyState(final ApplyState applyState) {
// Sanity check - we could get an ApplyState from a previous operation that timed out so make
// sure it's meant for us.
- if(operationContext.getContextId().equals(applyState.getIdentifier())) {
- LOG.info("{}: {} has been successfully replicated to a majority of followers", raftActor.getId(),
+ if (operationContext.getContextId().equals(applyState.getIdentifier())) {
+ LOG.info("{}: {} has been successfully replicated to a majority of followers", raftContext.getId(),
applyState.getReplicatedLogEntry().getData());
timer.cancel();
}
@Override
- public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ public void onServerOperationTimeout(final ServerOperationTimeout timeout) {
LOG.warn("{}: Timeout occured while replicating the new server configuration for {}", raftContext.getId(),
timeout.getLoggingContext());
// Fail any pending operations
ServerOperationContext<?> nextOperation = pendingOperationsQueue.poll();
- while(nextOperation != null) {
+ while (nextOperation != null) {
sendReply(nextOperation, ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT);
nextOperation = pendingOperationsQueue.poll();
}
}
@Override
- public void onNewOperation(ServerOperationContext<?> operationContext) {
- if(timedOut) {
- sendReply(operationContext, ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT);
+ public void onNewOperation(final ServerOperationContext<?> newOperationContext) {
+ if (timedOut) {
+ sendReply(newOperationContext, ServerChangeStatus.PRIOR_REQUEST_CONSENSUS_TIMEOUT);
} else {
- super.onNewOperation(operationContext);
+ super.onNewOperation(newOperationContext);
}
}
}
private abstract class AddServerState extends OperationState {
private final AddServerContext addServerContext;
- AddServerState(AddServerContext addServerContext) {
+ AddServerState(final AddServerContext addServerContext) {
this.addServerContext = addServerContext;
}
return newTimer(new ServerOperationTimeout(addServerContext.getOperation().getNewServerId()));
}
- void handleInstallSnapshotTimeout(ServerOperationTimeout timeout) {
+ void handleInstallSnapshotTimeout(final ServerOperationTimeout timeout) {
String serverId = timeout.getLoggingContext();
LOG.debug("{}: handleInstallSnapshotTimeout for new server {}", raftContext.getId(), serverId);
raftContext.removePeer(serverId);
boolean isLeader = raftActor.isLeader();
- if(isLeader) {
+ if (isLeader) {
AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
leader.removeFollower(serverId);
}
- operationComplete(getAddServerContext(), isLeader ? ServerChangeStatus.TIMEOUT : ServerChangeStatus.NO_LEADER);
+ operationComplete(getAddServerContext(), isLeader ? ServerChangeStatus.TIMEOUT
+ : ServerChangeStatus.NO_LEADER);
}
}
* snapshot capture, if necessary.
*/
private final class InitialAddServerState extends AddServerState implements InitialOperationState {
- InitialAddServerState(AddServerContext addServerContext) {
+ InitialAddServerState(final AddServerContext addServerContext) {
super(addServerContext);
}
@Override
public void initiate() {
- AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ final AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
AddServer addServer = getAddServerContext().getOperation();
LOG.debug("{}: Initiating {}", raftContext.getId(), addServer);
- if(raftContext.getPeerInfo(addServer.getNewServerId()) != null) {
+ if (raftContext.getPeerInfo(addServer.getNewServerId()) != null) {
operationComplete(getAddServerContext(), ServerChangeStatus.ALREADY_EXISTS);
return;
}
leader.addFollower(addServer.getNewServerId());
- if(votingState == VotingState.VOTING_NOT_INITIALIZED){
+ if (votingState == VotingState.VOTING_NOT_INITIALIZED) {
// schedule the install snapshot timeout timer
Cancellable installSnapshotTimer = newInstallSnapshotTimer();
- if(leader.initiateCaptureSnapshot(addServer.getNewServerId())) {
+ if (leader.initiateCaptureSnapshot(addServer.getNewServerId())) {
LOG.debug("{}: Initiating capture snapshot for new server {}", raftContext.getId(),
addServer.getNewServerId());
private final class InstallingSnapshot extends AddServerState {
private final Cancellable installSnapshotTimer;
- InstallingSnapshot(AddServerContext addServerContext, Cancellable installSnapshotTimer) {
+ InstallingSnapshot(final AddServerContext addServerContext, final Cancellable installSnapshotTimer) {
super(addServerContext);
this.installSnapshotTimer = Preconditions.checkNotNull(installSnapshotTimer);
}
@Override
- public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ public void onServerOperationTimeout(final ServerOperationTimeout timeout) {
handleInstallSnapshotTimeout(timeout);
LOG.warn("{}: Timeout occured for new server {} while installing snapshot", raftContext.getId(),
}
@Override
- public void onUnInitializedFollowerSnapshotReply(UnInitializedFollowerSnapshotReply reply) {
+ public void onUnInitializedFollowerSnapshotReply(final UnInitializedFollowerSnapshotReply reply) {
LOG.debug("{}: onUnInitializedFollowerSnapshotReply: {}", raftContext.getId(), reply);
String followerId = reply.getFollowerId();
// Sanity check to guard against receiving an UnInitializedFollowerSnapshotReply from a prior
// add server operation that timed out.
- if(getAddServerContext().getOperation().getNewServerId().equals(followerId) && raftActor.isLeader()) {
+ if (getAddServerContext().getOperation().getNewServerId().equals(followerId) && raftActor.isLeader()) {
AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
raftContext.getPeerInfo(followerId).setVotingState(VotingState.VOTING);
leader.updateMinReplicaCount();
private final class WaitingForPriorSnapshotComplete extends AddServerState {
private final Cancellable snapshotTimer;
- WaitingForPriorSnapshotComplete(AddServerContext addServerContext, Cancellable snapshotTimer) {
+ WaitingForPriorSnapshotComplete(final AddServerContext addServerContext, final Cancellable snapshotTimer) {
super(addServerContext);
this.snapshotTimer = Preconditions.checkNotNull(snapshotTimer);
}
public void onSnapshotComplete() {
LOG.debug("{}: onSnapshotComplete", raftContext.getId());
- if(!raftActor.isLeader()) {
+ if (!raftActor.isLeader()) {
LOG.debug("{}: No longer the leader", raftContext.getId());
return;
}
AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
- if(leader.initiateCaptureSnapshot(getAddServerContext().getOperation().getNewServerId())) {
+ if (leader.initiateCaptureSnapshot(getAddServerContext().getOperation().getNewServerId())) {
LOG.debug("{}: Initiating capture snapshot for new server {}", raftContext.getId(),
getAddServerContext().getOperation().getNewServerId());
}
@Override
- public void onServerOperationTimeout(ServerOperationTimeout timeout) {
+ public void onServerOperationTimeout(final ServerOperationTimeout timeout) {
handleInstallSnapshotTimeout(timeout);
LOG.warn("{}: Timeout occured for new server {} while waiting for prior snapshot to complete",
}
}
+ private static final class ServerOperationContextIdentifier
+ extends AbstractUUIDIdentifier<ServerOperationContextIdentifier> {
+ private static final long serialVersionUID = 1L;
+
+ ServerOperationContextIdentifier() {
+ super(UUID.randomUUID());
+ }
+ }
+
/**
* Stores context information for a server operation.
*
* @param <T> the operation type
*/
- private static abstract class ServerOperationContext<T> {
+ private abstract static class ServerOperationContext<T> {
private final T operation;
private final ActorRef clientRequestor;
- private final String contextId;
+ private final Identifier contextId;
- ServerOperationContext(T operation, ActorRef clientRequestor){
+ ServerOperationContext(final T operation, final ActorRef clientRequestor) {
this.operation = operation;
this.clientRequestor = clientRequestor;
- contextId = UUID.randomUUID().toString();
+ contextId = new ServerOperationContextIdentifier();
}
- String getContextId() {
+ Identifier getContextId() {
return contextId;
}
return clientRequestor;
}
- void operationComplete(RaftActor raftActor, boolean succeeded) {
+ void operationComplete(final RaftActor raftActor, final boolean succeeded) {
}
- boolean includeSelfInNewConfiguration(RaftActor raftActor) {
+ boolean includeSelfInNewConfiguration(final RaftActor raftActor) {
return true;
}
* Stores context information for an AddServer operation.
*/
private static class AddServerContext extends ServerOperationContext<AddServer> {
- AddServerContext(AddServer addServer, ActorRef clientRequestor) {
+ AddServerContext(final AddServer addServer, final ActorRef clientRequestor) {
super(addServer, clientRequestor);
}
@Override
- Object newReply(ServerChangeStatus status, String leaderId) {
+ Object newReply(final ServerChangeStatus status, final String leaderId) {
return new AddServerReply(status, leaderId);
}
@Override
- InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support) {
+ InitialOperationState newInitialOperationState(final RaftActorServerConfigurationSupport support) {
return support.new InitialAddServerState(this);
}
private abstract class RemoveServerState extends OperationState {
private final RemoveServerContext removeServerContext;
- protected RemoveServerState(RemoveServerContext removeServerContext) {
+ protected RemoveServerState(final RemoveServerContext removeServerContext) {
this.removeServerContext = Preconditions.checkNotNull(removeServerContext);
}
}
}
- private final class InitialRemoveServerState extends RemoveServerState implements InitialOperationState{
+ private final class InitialRemoveServerState extends RemoveServerState implements InitialOperationState {
- protected InitialRemoveServerState(RemoveServerContext removeServerContext) {
+ protected InitialRemoveServerState(final RemoveServerContext removeServerContext) {
super(removeServerContext);
}
public void initiate() {
String serverId = getRemoveServerContext().getOperation().getServerId();
raftContext.removePeer(serverId);
- ((AbstractLeader)raftActor.getCurrentBehavior()).removeFollower(serverId);
+ AbstractLeader leader = (AbstractLeader)raftActor.getCurrentBehavior();
+ leader.removeFollower(serverId);
+ leader.updateMinReplicaCount();
persistNewServerConfiguration(getRemoveServerContext());
}
private static class RemoveServerContext extends ServerOperationContext<RemoveServer> {
private final String peerAddress;
- RemoveServerContext(RemoveServer operation, String peerAddress, ActorRef clientRequestor) {
+ RemoveServerContext(final RemoveServer operation, final String peerAddress, final ActorRef clientRequestor) {
super(operation, clientRequestor);
this.peerAddress = peerAddress;
}
@Override
- Object newReply(ServerChangeStatus status, String leaderId) {
+ Object newReply(final ServerChangeStatus status, final String leaderId) {
return new RemoveServerReply(status, leaderId);
}
@Override
- InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support) {
+ InitialOperationState newInitialOperationState(final RaftActorServerConfigurationSupport support) {
return support.new InitialRemoveServerState(this);
}
@Override
- void operationComplete(RaftActor raftActor, boolean succeeded) {
- if(peerAddress != null) {
- raftActor.context().actorSelection(peerAddress).tell(new ServerRemoved(getOperation().getServerId()), raftActor.getSelf());
+ void operationComplete(final RaftActor raftActor, final boolean succeeded) {
+ if (peerAddress != null) {
+ raftActor.context().actorSelection(peerAddress).tell(
+ new ServerRemoved(getOperation().getServerId()), raftActor.getSelf());
}
}
@Override
- boolean includeSelfInNewConfiguration(RaftActor raftActor) {
+ boolean includeSelfInNewConfiguration(final RaftActor raftActor) {
return !getOperation().getServerId().equals(raftActor.getId());
}
}
private static class ChangeServersVotingStatusContext extends ServerOperationContext<ChangeServersVotingStatus> {
- ChangeServersVotingStatusContext(ChangeServersVotingStatus convertMessage, ActorRef clientRequestor) {
+ private final boolean tryToElectLeader;
+
+ ChangeServersVotingStatusContext(final ChangeServersVotingStatus convertMessage, final ActorRef clientRequestor,
+ final boolean tryToElectLeader) {
super(convertMessage, clientRequestor);
+ this.tryToElectLeader = tryToElectLeader;
}
@Override
- InitialOperationState newInitialOperationState(RaftActorServerConfigurationSupport support) {
- return support.new ChangeServersVotingStatusState(this);
+ InitialOperationState newInitialOperationState(final RaftActorServerConfigurationSupport support) {
+ return support.new ChangeServersVotingStatusState(this, tryToElectLeader);
}
@Override
- Object newReply(ServerChangeStatus status, String leaderId) {
+ Object newReply(final ServerChangeStatus status, final String leaderId) {
return new ServerChangeReply(status, leaderId);
}
@Override
- void operationComplete(final RaftActor raftActor, boolean succeeded) {
+ void operationComplete(final RaftActor raftActor, final boolean succeeded) {
// If this leader changed to non-voting we need to step down as leader so we'll try to transfer
// leadership.
- boolean localServerChangedToNonVoting = Boolean.FALSE.equals(getOperation().
- getServerVotingStatusMap().get(raftActor.getRaftActorContext().getId()));
- if(succeeded && localServerChangedToNonVoting && raftActor.isLeader()) {
- raftActor.initiateLeadershipTransfer(new OnComplete() {
- @Override
- public void onSuccess(ActorRef raftActorRef, ActorRef replyTo) {
- LOG.debug("{}: leader transfer succeeded after change to non-voting", raftActor.persistenceId());
- ensureFollowerState(raftActor);
- }
-
- @Override
- public void onFailure(ActorRef raftActorRef, ActorRef replyTo) {
- LOG.debug("{}: leader transfer failed after change to non-voting", raftActor.persistenceId());
- ensureFollowerState(raftActor);
- }
-
- private void ensureFollowerState(RaftActor raftActor) {
- // Whether or not leadership transfer succeeded, we have to step down as leader and
- // switch to Follower so ensure that.
- if(raftActor.getRaftState() != RaftState.Follower) {
- raftActor.initializeBehavior();
- }
- }
- });
+ boolean localServerChangedToNonVoting = Boolean.FALSE.equals(getOperation()
+ .getServerVotingStatusMap().get(raftActor.getRaftActorContext().getId()));
+ if (succeeded && localServerChangedToNonVoting) {
+ LOG.debug("Leader changed to non-voting - trying leadership transfer");
+ raftActor.becomeNonVoting();
+ } else if (raftActor.isLeader()) {
+ raftActor.onVotingStateChangeComplete();
}
}
@Override
String getLoggingContext() {
- return getOperation().getServerVotingStatusMap().toString();
+ return getOperation().toString();
}
}
private class ChangeServersVotingStatusState extends OperationState implements InitialOperationState {
private final ChangeServersVotingStatusContext changeVotingStatusContext;
+ private final boolean tryToElectLeader;
- ChangeServersVotingStatusState(ChangeServersVotingStatusContext changeVotingStatusContext) {
+ ChangeServersVotingStatusState(final ChangeServersVotingStatusContext changeVotingStatusContext,
+ final boolean tryToElectLeader) {
this.changeVotingStatusContext = changeVotingStatusContext;
+ this.tryToElectLeader = tryToElectLeader;
}
@Override
public void initiate() {
LOG.debug("Initiating ChangeServersVotingStatusState");
- Map<String, Boolean> serverVotingStatusMap = changeVotingStatusContext.getOperation().getServerVotingStatusMap();
+ if (tryToElectLeader) {
+ initiateLocalLeaderElection();
+ } else if (updateLocalPeerInfo()) {
+ persistNewServerConfiguration(changeVotingStatusContext);
+ }
+ }
+
+ private void initiateLocalLeaderElection() {
+ LOG.debug("{}: Sending local ElectionTimeout to start leader election", raftContext.getId());
+
+ ServerConfigurationPayload previousServerConfig = raftContext.getPeerServerInfo(true);
+ if (!updateLocalPeerInfo()) {
+ return;
+ }
+
+ raftContext.getActor().tell(TimeoutNow.INSTANCE, raftContext.getActor());
+
+ currentOperationState = new WaitingForLeaderElected(changeVotingStatusContext, previousServerConfig);
+ }
+
+ private boolean updateLocalPeerInfo() {
+ List<ServerInfo> newServerInfoList = newServerInfoList();
+
+ // Check if new voting state would leave us with no voting members.
+ boolean atLeastOneVoting = false;
+ for (ServerInfo info: newServerInfoList) {
+ if (info.isVoting()) {
+ atLeastOneVoting = true;
+ break;
+ }
+ }
+
+ if (!atLeastOneVoting) {
+ operationComplete(changeVotingStatusContext, ServerChangeStatus.INVALID_REQUEST);
+ return false;
+ }
+
+ raftContext.updatePeerIds(new ServerConfigurationPayload(newServerInfoList));
+ if (raftActor.getCurrentBehavior() instanceof AbstractLeader) {
+ AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
+ leader.updateMinReplicaCount();
+ }
+
+ return true;
+ }
+
+ private List<ServerInfo> newServerInfoList() {
+ Map<String, Boolean> serverVotingStatusMap = changeVotingStatusContext.getOperation()
+ .getServerVotingStatusMap();
List<ServerInfo> newServerInfoList = new ArrayList<>();
- for(String peerId: raftContext.getPeerIds()) {
- newServerInfoList.add(new ServerInfo(peerId, serverVotingStatusMap.containsKey(peerId) ?
- serverVotingStatusMap.get(peerId) : raftContext.getPeerInfo(peerId).isVoting()));
+ for (String peerId: raftContext.getPeerIds()) {
+ newServerInfoList.add(new ServerInfo(peerId, serverVotingStatusMap.containsKey(peerId)
+ ? serverVotingStatusMap.get(peerId) : raftContext.getPeerInfo(peerId).isVoting()));
}
newServerInfoList.add(new ServerInfo(raftContext.getId(), serverVotingStatusMap.containsKey(
- raftContext.getId()) ? serverVotingStatusMap.get(raftContext.getId()) : raftContext.isVotingMember()));
+ raftContext.getId()) ? serverVotingStatusMap.get(raftContext.getId())
+ : raftContext.isVotingMember()));
- raftContext.updatePeerIds(new ServerConfigurationPayload(newServerInfoList));
- AbstractLeader leader = (AbstractLeader) raftActor.getCurrentBehavior();
- leader.updateMinReplicaCount();
+ return newServerInfoList;
+ }
+ }
+
+ private class WaitingForLeaderElected extends OperationState {
+ private final ServerConfigurationPayload previousServerConfig;
+ private final ChangeServersVotingStatusContext operationContext;
+ private final Cancellable timer;
- persistNewServerConfiguration(changeVotingStatusContext);
+ WaitingForLeaderElected(final ChangeServersVotingStatusContext operationContext,
+ final ServerConfigurationPayload previousServerConfig) {
+ this.operationContext = operationContext;
+ this.previousServerConfig = previousServerConfig;
+
+ timer = newTimer(raftContext.getConfigParams().getElectionTimeOutInterval(),
+ new ServerOperationTimeout(operationContext.getLoggingContext()));
+ }
+
+ @Override
+ void onNewLeader(final String newLeader) {
+ if (newLeader == null) {
+ return;
+ }
+
+ LOG.debug("{}: New leader {} elected", raftContext.getId(), newLeader);
+
+ timer.cancel();
+
+ if (raftActor.isLeader()) {
+ persistNewServerConfiguration(operationContext);
+ } else {
+ // Edge case - some other node became leader so forward the operation.
+ LOG.debug("{}: Forwarding {} to new leader", raftContext.getId(), operationContext.getOperation());
+
+ // Revert the local server config change.
+ raftContext.updatePeerIds(previousServerConfig);
+
+ changeToIdleState();
+ RaftActorServerConfigurationSupport.this.onNewOperation(operationContext);
+ }
+ }
+
+ @Override
+ void onServerOperationTimeout(final ServerOperationTimeout timeout) {
+ LOG.warn("{}: Leader election timed out - cannot apply operation {}",
+ raftContext.getId(), timeout.getLoggingContext());
+
+ // Revert the local server config change.
+ raftContext.updatePeerIds(previousServerConfig);
+ raftActor.initializeBehavior();
+
+ tryToForwardOperationToAnotherServer();
+ }
+
+ private void tryToForwardOperationToAnotherServer() {
+ Collection<String> serversVisited = new HashSet<>(operationContext.getOperation().getServersVisited());
+
+ LOG.debug("{}: tryToForwardOperationToAnotherServer - servers already visited {}", raftContext.getId(),
+ serversVisited);
+
+ serversVisited.add(raftContext.getId());
+
+ // Try to find another whose state is being changed from non-voting to voting and that we haven't
+ // tried yet.
+ Map<String, Boolean> serverVotingStatusMap = operationContext.getOperation().getServerVotingStatusMap();
+ ActorSelection forwardToPeerActor = null;
+ for (Map.Entry<String, Boolean> e: serverVotingStatusMap.entrySet()) {
+ Boolean isVoting = e.getValue();
+ String serverId = e.getKey();
+ PeerInfo peerInfo = raftContext.getPeerInfo(serverId);
+ if (isVoting && peerInfo != null && !peerInfo.isVoting() && !serversVisited.contains(serverId)) {
+ ActorSelection actor = raftContext.getPeerActorSelection(serverId);
+ if (actor != null) {
+ forwardToPeerActor = actor;
+ break;
+ }
+ }
+ }
+
+ if (forwardToPeerActor != null) {
+ LOG.debug("{}: Found server {} to forward to", raftContext.getId(), forwardToPeerActor);
+
+ forwardToPeerActor.tell(new ChangeServersVotingStatus(serverVotingStatusMap, serversVisited),
+ operationContext.getClientRequestor());
+ changeToIdleState();
+ } else {
+ operationComplete(operationContext, ServerChangeStatus.NO_LEADER);
+ }
}
}
static class ServerOperationTimeout {
private final String loggingContext;
- ServerOperationTimeout(String loggingContext){
- this.loggingContext = Preconditions.checkNotNull(loggingContext, "loggingContext should not be null");
+ ServerOperationTimeout(final String loggingContext) {
+ this.loggingContext = Preconditions.checkNotNull(loggingContext, "loggingContext should not be null");
}
String getLoggingContext() {
Code Review / controller.git / blobdiff