Introduce PreVoteCollector (#32847)
An election requires a node to select a term that is higher than all previously-seen terms. If nodes are too enthusiastic about starting elections then they can effectively excludes itself from the cluster until the leader can bump to a still-higher term, and if this process repeats then a single faulty node can prevent the cluster from making useful progress. The solution is to start the election with a pre-voting round to ensure that there is at least a quorum of nodes who believe there to be no leader. This also fixes up some merge issues.
This commit is contained in:
David Turner
GitHub
parent
f6891cd222
commit
cd6326b391
|
|
@ -99,7 +99,12 @@ public class CoordinationState extends AbstractComponent {
|
|||
}
|
||||
|
||||
public boolean isElectionQuorum(VoteCollection votes) {
|
||||
return votes.isQuorum(getLastCommittedConfiguration()) && votes.isQuorum(getLastAcceptedConfiguration());
|
||||
return isElectionQuorum(votes, getLastAcceptedState());
|
||||
}
|
||||
|
||||
static boolean isElectionQuorum(VoteCollection votes, ClusterState lastAcceptedState) {
|
||||
return votes.isQuorum(lastAcceptedState.getLastCommittedConfiguration())
|
||||
&& votes.isQuorum(lastAcceptedState.getLastAcceptedConfiguration());
|
||||
}
|
||||
|
||||
public boolean isPublishQuorum(VoteCollection votes) {
|
||||
|
|
|
|||
|
|
@ -0,0 +1,202 @@
|
|||
/*
|
||||
* Licensed to Elasticsearch under one or more contributor
|
||||
* license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright
|
||||
* ownership. Elasticsearch licenses this file to you under
|
||||
* the Apache License, Version 2.0 (the "License"); you may
|
||||
* not use this file except in compliance with the License.
|
||||
* You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing,
|
||||
* software distributed under the License is distributed on an
|
||||
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
||||
* KIND, either express or implied. See the License for the
|
||||
* specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*/
|
||||
|
||||
package org.elasticsearch.cluster.coordination;
|
||||
|
||||
import org.apache.logging.log4j.message.ParameterizedMessage;
|
||||
import org.elasticsearch.cluster.ClusterState;
|
||||
import org.elasticsearch.cluster.coordination.CoordinationState.VoteCollection;
|
||||
import org.elasticsearch.cluster.node.DiscoveryNode;
|
||||
import org.elasticsearch.common.collect.Tuple;
|
||||
import org.elasticsearch.common.component.AbstractComponent;
|
||||
import org.elasticsearch.common.lease.Releasable;
|
||||
import org.elasticsearch.common.settings.Settings;
|
||||
import org.elasticsearch.threadpool.ThreadPool.Names;
|
||||
import org.elasticsearch.transport.TransportException;
|
||||
import org.elasticsearch.transport.TransportResponseHandler;
|
||||
import org.elasticsearch.transport.TransportService;
|
||||
|
||||
import java.util.Set;
|
||||
import java.util.concurrent.atomic.AtomicBoolean;
|
||||
|
||||
import static org.elasticsearch.cluster.coordination.CoordinationState.isElectionQuorum;
|
||||
import static org.elasticsearch.common.util.concurrent.ConcurrentCollections.newConcurrentSet;
|
||||
|
||||
public class PreVoteCollector extends AbstractComponent {
|
||||
|
||||
public static final String REQUEST_PRE_VOTE_ACTION_NAME = "internal:cluster/request_pre_vote";
|
||||
|
||||
private final TransportService transportService;
|
||||
private final Runnable startElection;
|
||||
|
||||
// Tuple for simple atomic updates
|
||||
private volatile Tuple<DiscoveryNode, PreVoteResponse> state; // DiscoveryNode component is null if there is currently no known leader
|
||||
|
||||
PreVoteCollector(final Settings settings, final PreVoteResponse preVoteResponse,
|
||||
final TransportService transportService, final Runnable startElection) {
|
||||
super(settings);
|
||||
state = new Tuple<>(null, preVoteResponse);
|
||||
this.transportService = transportService;
|
||||
this.startElection = startElection;
|
||||
|
||||
// TODO does this need to be on the generic threadpool or can it use SAME?
|
||||
transportService.registerRequestHandler(REQUEST_PRE_VOTE_ACTION_NAME, Names.GENERIC, false, false,
|
||||
PreVoteRequest::new,
|
||||
(request, channel, task) -> channel.sendResponse(handlePreVoteRequest(request)));
|
||||
}
|
||||
|
||||
/**
|
||||
* Start a new pre-voting round.
|
||||
*
|
||||
* @param clusterState the last-accepted cluster state
|
||||
* @param broadcastNodes the nodes from whom to request pre-votes
|
||||
* @return the pre-voting round, which can be closed to end the round early.
|
||||
*/
|
||||
public Releasable start(final ClusterState clusterState, final Iterable<DiscoveryNode> broadcastNodes) {
|
||||
PreVotingRound preVotingRound = new PreVotingRound(clusterState, state.v2().getCurrentTerm());
|
||||
preVotingRound.start(broadcastNodes);
|
||||
return preVotingRound;
|
||||
}
|
||||
|
||||
public void update(final PreVoteResponse preVoteResponse, final DiscoveryNode leader) {
|
||||
logger.trace("updating with preVoteResponse={}, leader={}", preVoteResponse, leader);
|
||||
state = new Tuple<>(leader, preVoteResponse);
|
||||
}
|
||||
|
||||
private PreVoteResponse handlePreVoteRequest(final PreVoteRequest request) {
|
||||
// TODO if we are a leader and the max term seen exceeds our term then we need to bump our term
|
||||
|
||||
Tuple<DiscoveryNode, PreVoteResponse> state = this.state;
|
||||
final DiscoveryNode leader = state.v1();
|
||||
|
||||
if (leader == null) {
|
||||
return state.v2();
|
||||
}
|
||||
|
||||
if (leader.equals(request.getSourceNode())) {
|
||||
// This is a _rare_ case where our leader has detected a failure and stepped down, but we are still a follower. It's possible
|
||||
// that the leader lost its quorum, but while we're still a follower we will not offer joins to any other node so there is no
|
||||
// major drawback in offering a join to our old leader. The advantage of this is that it makes it slightly more likely that the
|
||||
// leader won't change, and also that its re-election will happen more quickly than if it had to wait for a quorum of followers
|
||||
// to also detect its failure.
|
||||
return state.v2();
|
||||
}
|
||||
|
||||
throw new CoordinationStateRejectedException("rejecting " + request + " as there is already a leader");
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "PreVoteCollector{" +
|
||||
"state=" + state +
|
||||
'}';
|
||||
}
|
||||
|
||||
private class PreVotingRound implements Releasable {
|
||||
private final Set<DiscoveryNode> preVotesReceived = newConcurrentSet();
|
||||
private final AtomicBoolean electionStarted = new AtomicBoolean();
|
||||
private final PreVoteRequest preVoteRequest;
|
||||
private final ClusterState clusterState;
|
||||
private final AtomicBoolean isClosed = new AtomicBoolean();
|
||||
|
||||
PreVotingRound(final ClusterState clusterState, final long currentTerm) {
|
||||
this.clusterState = clusterState;
|
||||
preVoteRequest = new PreVoteRequest(transportService.getLocalNode(), currentTerm);
|
||||
}
|
||||
|
||||
void start(final Iterable<DiscoveryNode> broadcastNodes) {
|
||||
logger.debug("{} requesting pre-votes from {}", this, broadcastNodes);
|
||||
broadcastNodes.forEach(n -> transportService.sendRequest(n, REQUEST_PRE_VOTE_ACTION_NAME, preVoteRequest,
|
||||
new TransportResponseHandler<PreVoteResponse>() {
|
||||
@Override
|
||||
public void handleResponse(PreVoteResponse response) {
|
||||
handlePreVoteResponse(response, n);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void handleException(TransportException exp) {
|
||||
if (exp.getRootCause() instanceof CoordinationStateRejectedException) {
|
||||
logger.debug("{} failed: {}", this, exp.getRootCause().getMessage());
|
||||
} else {
|
||||
logger.debug(new ParameterizedMessage("{} failed", this), exp);
|
||||
}
|
||||
}
|
||||
|
||||
@Override
|
||||
public String executor() {
|
||||
return Names.GENERIC;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "TransportResponseHandler{" + PreVoteCollector.this + ", node=" + n + '}';
|
||||
}
|
||||
}));
|
||||
}
|
||||
|
||||
private void handlePreVoteResponse(final PreVoteResponse response, final DiscoveryNode sender) {
|
||||
if (isClosed.get()) {
|
||||
logger.debug("{} is closed, ignoring {} from {}", this, response, sender);
|
||||
return;
|
||||
}
|
||||
|
||||
// TODO the response carries the sender's current term. If an election starts then it should be in a higher term.
|
||||
|
||||
if (response.getLastAcceptedTerm() > clusterState.term()
|
||||
|| (response.getLastAcceptedTerm() == clusterState.term()
|
||||
&& response.getLastAcceptedVersion() > clusterState.version())) {
|
||||
logger.debug("{} ignoring {} from {} as it is fresher", this, response, sender);
|
||||
return;
|
||||
}
|
||||
|
||||
preVotesReceived.add(sender);
|
||||
final VoteCollection voteCollection = new VoteCollection();
|
||||
preVotesReceived.forEach(voteCollection::addVote);
|
||||
|
||||
if (isElectionQuorum(voteCollection, clusterState) == false) {
|
||||
logger.debug("{} added {} from {}, no quorum yet", this, response, sender);
|
||||
return;
|
||||
}
|
||||
|
||||
if (electionStarted.compareAndSet(false, true) == false) {
|
||||
logger.debug("{} added {} from {} but election has already started", this, response, sender);
|
||||
return;
|
||||
}
|
||||
|
||||
logger.debug("{} added {} from {}, starting election", this, response, sender);
|
||||
startElection.run();
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "PreVotingRound{" +
|
||||
"preVotesReceived=" + preVotesReceived +
|
||||
", electionStarted=" + electionStarted +
|
||||
", preVoteRequest=" + preVoteRequest +
|
||||
", isClosed=" + isClosed +
|
||||
'}';
|
||||
}
|
||||
|
||||
@Override
|
||||
public void close() {
|
||||
final boolean isNotAlreadyClosed = isClosed.compareAndSet(false, true);
|
||||
assert isNotAlreadyClosed;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,82 @@
|
|||
/*
|
||||
* Licensed to Elasticsearch under one or more contributor
|
||||
* license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright
|
||||
* ownership. Elasticsearch licenses this file to you under
|
||||
* the Apache License, Version 2.0 (the "License"); you may
|
||||
* not use this file except in compliance with the License.
|
||||
* You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing,
|
||||
* software distributed under the License is distributed on an
|
||||
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
||||
* KIND, either express or implied. See the License for the
|
||||
* specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*/
|
||||
|
||||
package org.elasticsearch.cluster.coordination;
|
||||
|
||||
import org.elasticsearch.cluster.node.DiscoveryNode;
|
||||
import org.elasticsearch.common.io.stream.StreamInput;
|
||||
import org.elasticsearch.common.io.stream.StreamOutput;
|
||||
import org.elasticsearch.transport.TransportRequest;
|
||||
|
||||
import java.io.IOException;
|
||||
import java.util.Objects;
|
||||
|
||||
public class PreVoteRequest extends TransportRequest {
|
||||
|
||||
private final DiscoveryNode sourceNode;
|
||||
private final long currentTerm;
|
||||
|
||||
public PreVoteRequest(DiscoveryNode sourceNode, long currentTerm) {
|
||||
this.sourceNode = sourceNode;
|
||||
this.currentTerm = currentTerm;
|
||||
}
|
||||
|
||||
public PreVoteRequest(StreamInput in) throws IOException {
|
||||
super(in);
|
||||
sourceNode = new DiscoveryNode(in);
|
||||
currentTerm = in.readLong();
|
||||
}
|
||||
|
||||
@Override
|
||||
public void writeTo(StreamOutput out) throws IOException {
|
||||
super.writeTo(out);
|
||||
sourceNode.writeTo(out);
|
||||
out.writeLong(currentTerm);
|
||||
}
|
||||
|
||||
public DiscoveryNode getSourceNode() {
|
||||
return sourceNode;
|
||||
}
|
||||
|
||||
public long getCurrentTerm() {
|
||||
return currentTerm;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "PreVoteRequest{" +
|
||||
"sourceNode=" + sourceNode +
|
||||
", currentTerm=" + currentTerm +
|
||||
'}';
|
||||
}
|
||||
|
||||
@Override
|
||||
public boolean equals(Object o) {
|
||||
if (this == o) return true;
|
||||
if (o == null || getClass() != o.getClass()) return false;
|
||||
PreVoteRequest that = (PreVoteRequest) o;
|
||||
return currentTerm == that.currentTerm &&
|
||||
Objects.equals(sourceNode, that.sourceNode);
|
||||
}
|
||||
|
||||
@Override
|
||||
public int hashCode() {
|
||||
return Objects.hash(sourceNode, currentTerm);
|
||||
}
|
||||
}
|
||||
|
|
@ -0,0 +1,91 @@
|
|||
/*
|
||||
* Licensed to Elasticsearch under one or more contributor
|
||||
* license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright
|
||||
* ownership. Elasticsearch licenses this file to you under
|
||||
* the Apache License, Version 2.0 (the "License"); you may
|
||||
* not use this file except in compliance with the License.
|
||||
* You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing,
|
||||
* software distributed under the License is distributed on an
|
||||
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
||||
* KIND, either express or implied. See the License for the
|
||||
* specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*/
|
||||
|
||||
package org.elasticsearch.cluster.coordination;
|
||||
|
||||
import org.elasticsearch.common.io.stream.StreamInput;
|
||||
import org.elasticsearch.common.io.stream.StreamOutput;
|
||||
import org.elasticsearch.transport.TransportResponse;
|
||||
|
||||
import java.io.IOException;
|
||||
import java.util.Objects;
|
||||
|
||||
public class PreVoteResponse extends TransportResponse {
|
||||
private final long currentTerm;
|
||||
private final long lastAcceptedTerm;
|
||||
private final long lastAcceptedVersion;
|
||||
|
||||
public PreVoteResponse(long currentTerm, long lastAcceptedTerm, long lastAcceptedVersion) {
|
||||
this.currentTerm = currentTerm;
|
||||
this.lastAcceptedTerm = lastAcceptedTerm;
|
||||
this.lastAcceptedVersion = lastAcceptedVersion;
|
||||
assert lastAcceptedTerm <= currentTerm : currentTerm + " < " + lastAcceptedTerm;
|
||||
}
|
||||
|
||||
public PreVoteResponse(StreamInput in) throws IOException {
|
||||
currentTerm = in.readLong();
|
||||
lastAcceptedTerm = in.readLong();
|
||||
lastAcceptedVersion = in.readLong();
|
||||
assert lastAcceptedTerm <= currentTerm : currentTerm + " < " + lastAcceptedTerm;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void writeTo(StreamOutput out) throws IOException {
|
||||
super.writeTo(out);
|
||||
out.writeLong(currentTerm);
|
||||
out.writeLong(lastAcceptedTerm);
|
||||
out.writeLong(lastAcceptedVersion);
|
||||
}
|
||||
|
||||
public long getCurrentTerm() {
|
||||
return currentTerm;
|
||||
}
|
||||
|
||||
public long getLastAcceptedTerm() {
|
||||
return lastAcceptedTerm;
|
||||
}
|
||||
|
||||
public long getLastAcceptedVersion() {
|
||||
return lastAcceptedVersion;
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "PreVoteResponse{" +
|
||||
"currentTerm=" + currentTerm +
|
||||
", lastAcceptedTerm=" + lastAcceptedTerm +
|
||||
", lastAcceptedVersion=" + lastAcceptedVersion +
|
||||
'}';
|
||||
}
|
||||
|
||||
@Override
|
||||
public boolean equals(Object o) {
|
||||
if (this == o) return true;
|
||||
if (o == null || getClass() != o.getClass()) return false;
|
||||
PreVoteResponse that = (PreVoteResponse) o;
|
||||
return currentTerm == that.currentTerm &&
|
||||
lastAcceptedTerm == that.lastAcceptedTerm &&
|
||||
lastAcceptedVersion == that.lastAcceptedVersion;
|
||||
}
|
||||
|
||||
@Override
|
||||
public int hashCode() {
|
||||
return Objects.hash(currentTerm, lastAcceptedTerm, lastAcceptedVersion);
|
||||
}
|
||||
}
|
||||
|
|
@ -174,4 +174,50 @@ public class MessagesTests extends ESTestCase {
|
|||
new ClusterState.VotingConfiguration(Sets.newHashSet(generateRandomStringArray(10, 10, false))),
|
||||
randomLong());
|
||||
}
|
||||
|
||||
public void testPreVoteRequestEqualsHashCodeSerialization() {
|
||||
PreVoteRequest initialPreVoteRequest = new PreVoteRequest(createNode(randomAlphaOfLength(10)), randomNonNegativeLong());
|
||||
EqualsHashCodeTestUtils.checkEqualsAndHashCode(initialPreVoteRequest,
|
||||
preVoteRequest -> copyWriteable(preVoteRequest, writableRegistry(), PreVoteRequest::new),
|
||||
preVoteRequest -> {
|
||||
if (randomBoolean()) {
|
||||
return new PreVoteRequest(createNode(randomAlphaOfLength(10)), preVoteRequest.getCurrentTerm());
|
||||
} else {
|
||||
return new PreVoteRequest(preVoteRequest.getSourceNode(), randomNonNegativeLong());
|
||||
}
|
||||
});
|
||||
}
|
||||
|
||||
public void testPreVoteResponseEqualsHashCodeSerialization() {
|
||||
long currentTerm = randomNonNegativeLong();
|
||||
PreVoteResponse initialPreVoteResponse
|
||||
= new PreVoteResponse(currentTerm, randomLongBetween(1, currentTerm), randomNonNegativeLong());
|
||||
EqualsHashCodeTestUtils.checkEqualsAndHashCode(initialPreVoteResponse,
|
||||
preVoteResponse -> copyWriteable(preVoteResponse, writableRegistry(), PreVoteResponse::new),
|
||||
preVoteResponse -> {
|
||||
switch (randomInt(2)) {
|
||||
case 0:
|
||||
assumeTrue("last-accepted term is Long.MAX_VALUE", preVoteResponse.getLastAcceptedTerm() < Long.MAX_VALUE);
|
||||
return new PreVoteResponse(
|
||||
randomValueOtherThan(preVoteResponse.getCurrentTerm(),
|
||||
() -> randomLongBetween(preVoteResponse.getLastAcceptedTerm(), Long.MAX_VALUE)),
|
||||
preVoteResponse.getLastAcceptedTerm(),
|
||||
preVoteResponse.getLastAcceptedVersion());
|
||||
case 1:
|
||||
assumeTrue("current term is 1", 1 < preVoteResponse.getCurrentTerm());
|
||||
return new PreVoteResponse(
|
||||
preVoteResponse.getCurrentTerm(),
|
||||
randomValueOtherThan(preVoteResponse.getLastAcceptedTerm(),
|
||||
() -> randomLongBetween(1, preVoteResponse.getCurrentTerm())),
|
||||
preVoteResponse.getLastAcceptedVersion());
|
||||
case 2:
|
||||
return new PreVoteResponse(
|
||||
preVoteResponse.getCurrentTerm(),
|
||||
preVoteResponse.getLastAcceptedTerm(),
|
||||
randomValueOtherThan(preVoteResponse.getLastAcceptedVersion(), ESTestCase::randomNonNegativeLong));
|
||||
default:
|
||||
throw new AssertionError();
|
||||
}
|
||||
});
|
||||
}
|
||||
}
|
||||
|
|
|
|||
|
|
@ -0,0 +1,329 @@
|
|||
/*
|
||||
* Licensed to Elasticsearch under one or more contributor
|
||||
* license agreements. See the NOTICE file distributed with
|
||||
* this work for additional information regarding copyright
|
||||
* ownership. Elasticsearch licenses this file to you under
|
||||
* the Apache License, Version 2.0 (the "License"); you may
|
||||
* not use this file except in compliance with the License.
|
||||
* You may obtain a copy of the License at
|
||||
*
|
||||
* http://www.apache.org/licenses/LICENSE-2.0
|
||||
*
|
||||
* Unless required by applicable law or agreed to in writing,
|
||||
* software distributed under the License is distributed on an
|
||||
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
|
||||
* KIND, either express or implied. See the License for the
|
||||
* specific language governing permissions and limitations
|
||||
* under the License.
|
||||
*/
|
||||
|
||||
package org.elasticsearch.cluster.coordination;
|
||||
|
||||
import org.elasticsearch.Version;
|
||||
import org.elasticsearch.cluster.ClusterState;
|
||||
import org.elasticsearch.cluster.ClusterState.VotingConfiguration;
|
||||
import org.elasticsearch.cluster.coordination.CoordinationStateTests.InMemoryPersistedState;
|
||||
import org.elasticsearch.cluster.node.DiscoveryNode;
|
||||
import org.elasticsearch.common.lease.Releasable;
|
||||
import org.elasticsearch.common.settings.Settings;
|
||||
import org.elasticsearch.test.ESTestCase;
|
||||
import org.elasticsearch.test.transport.CapturingTransport;
|
||||
import org.elasticsearch.transport.ConnectTransportException;
|
||||
import org.elasticsearch.transport.RemoteTransportException;
|
||||
import org.elasticsearch.transport.TransportException;
|
||||
import org.elasticsearch.transport.TransportRequest;
|
||||
import org.elasticsearch.transport.TransportResponseHandler;
|
||||
import org.elasticsearch.transport.TransportService;
|
||||
import org.junit.Before;
|
||||
|
||||
import java.util.Arrays;
|
||||
import java.util.HashMap;
|
||||
import java.util.HashSet;
|
||||
import java.util.Map;
|
||||
import java.util.Objects;
|
||||
import java.util.Set;
|
||||
import java.util.concurrent.atomic.AtomicReference;
|
||||
import java.util.stream.Collectors;
|
||||
|
||||
import static java.util.Collections.emptySet;
|
||||
import static org.elasticsearch.cluster.coordination.PreVoteCollector.REQUEST_PRE_VOTE_ACTION_NAME;
|
||||
import static org.elasticsearch.node.Node.NODE_NAME_SETTING;
|
||||
import static org.elasticsearch.threadpool.ThreadPool.Names.SAME;
|
||||
import static org.hamcrest.Matchers.equalTo;
|
||||
import static org.hamcrest.Matchers.instanceOf;
|
||||
import static org.hamcrest.Matchers.is;
|
||||
import static org.hamcrest.Matchers.not;
|
||||
import static org.hamcrest.Matchers.nullValue;
|
||||
|
||||
public class PreVoteCollectorTests extends ESTestCase {
|
||||
|
||||
private DeterministicTaskQueue deterministicTaskQueue;
|
||||
private PreVoteCollector preVoteCollector;
|
||||
private boolean electionOccurred = false;
|
||||
private DiscoveryNode localNode;
|
||||
private Map<DiscoveryNode, PreVoteResponse> responsesByNode = new HashMap<>();
|
||||
private long currentTerm, lastAcceptedTerm, lastAcceptedVersion;
|
||||
private TransportService transportService;
|
||||
|
||||
@Before
|
||||
public void createObjects() {
|
||||
Settings settings = Settings.builder().put(NODE_NAME_SETTING.getKey(), "node").build();
|
||||
deterministicTaskQueue = new DeterministicTaskQueue(settings);
|
||||
final CapturingTransport capturingTransport = new CapturingTransport() {
|
||||
@Override
|
||||
protected void onSendRequest(final long requestId, final String action, final TransportRequest request,
|
||||
final DiscoveryNode node) {
|
||||
super.onSendRequest(requestId, action, request, node);
|
||||
assertThat(action, is(REQUEST_PRE_VOTE_ACTION_NAME));
|
||||
assertThat(request, instanceOf(PreVoteRequest.class));
|
||||
assertThat(node, not(equalTo(localNode)));
|
||||
PreVoteRequest preVoteRequest = (PreVoteRequest) request;
|
||||
assertThat(preVoteRequest.getSourceNode(), equalTo(localNode));
|
||||
deterministicTaskQueue.scheduleNow(new Runnable() {
|
||||
@Override
|
||||
public void run() {
|
||||
final PreVoteResponse response = responsesByNode.get(node);
|
||||
if (response == null) {
|
||||
handleRemoteError(requestId, new ConnectTransportException(node, "no response"));
|
||||
} else {
|
||||
handleResponse(requestId, response);
|
||||
}
|
||||
}
|
||||
|
||||
@Override
|
||||
public String toString() {
|
||||
return "response to " + request + " from " + node;
|
||||
}
|
||||
});
|
||||
}
|
||||
};
|
||||
lastAcceptedTerm = randomNonNegativeLong();
|
||||
currentTerm = randomLongBetween(lastAcceptedTerm, Long.MAX_VALUE);
|
||||
lastAcceptedVersion = randomNonNegativeLong();
|
||||
|
||||
localNode = new DiscoveryNode("local-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(localNode, new PreVoteResponse(currentTerm, lastAcceptedTerm, lastAcceptedVersion));
|
||||
transportService = capturingTransport.createCapturingTransportService(settings,
|
||||
deterministicTaskQueue.getThreadPool(), TransportService.NOOP_TRANSPORT_INTERCEPTOR,
|
||||
boundTransportAddress -> localNode, null, emptySet());
|
||||
transportService.start();
|
||||
transportService.acceptIncomingRequests();
|
||||
|
||||
preVoteCollector = new PreVoteCollector(settings, getLocalPreVoteResponse(), transportService, () -> {
|
||||
assert electionOccurred == false;
|
||||
electionOccurred = true;
|
||||
});
|
||||
}
|
||||
|
||||
private PreVoteResponse getLocalPreVoteResponse() {
|
||||
return Objects.requireNonNull(responsesByNode.get(localNode));
|
||||
}
|
||||
|
||||
private void startAndRunCollector(DiscoveryNode... votingNodes) {
|
||||
try (Releasable ignored = startCollector(votingNodes)) {
|
||||
runCollector();
|
||||
}
|
||||
}
|
||||
|
||||
private void runCollector() {
|
||||
deterministicTaskQueue.runAllRunnableTasks(random());
|
||||
assertFalse(deterministicTaskQueue.hasDeferredTasks());
|
||||
assertFalse(deterministicTaskQueue.hasRunnableTasks());
|
||||
}
|
||||
|
||||
private ClusterState makeClusterState(DiscoveryNode[] votingNodes) {
|
||||
final VotingConfiguration votingConfiguration
|
||||
= new VotingConfiguration(Arrays.stream(votingNodes).map(DiscoveryNode::getId).collect(Collectors.toSet()));
|
||||
return CoordinationStateTests.clusterState(lastAcceptedTerm, lastAcceptedVersion, localNode,
|
||||
votingConfiguration, votingConfiguration, 0);
|
||||
}
|
||||
|
||||
private Releasable startCollector(DiscoveryNode... votingNodes) {
|
||||
return preVoteCollector.start(makeClusterState(votingNodes), responsesByNode.keySet());
|
||||
}
|
||||
|
||||
public void testStartsElectionIfLocalNodeIsOnlyNode() {
|
||||
startAndRunCollector(localNode);
|
||||
assertTrue(electionOccurred);
|
||||
}
|
||||
|
||||
public void testStartsElectionIfLocalNodeIsQuorum() {
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode, getLocalPreVoteResponse());
|
||||
startAndRunCollector(otherNode);
|
||||
assertTrue(electionOccurred);
|
||||
}
|
||||
|
||||
|
||||
public void testStartsElectionIfOtherNodeIsQuorum() {
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode, getLocalPreVoteResponse());
|
||||
startAndRunCollector(otherNode);
|
||||
assertTrue(electionOccurred);
|
||||
}
|
||||
|
||||
public void testDoesNotStartsElectionIfOtherNodeIsQuorumAndDoesNotRespond() {
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode, null);
|
||||
startAndRunCollector(otherNode);
|
||||
assertFalse(electionOccurred);
|
||||
}
|
||||
|
||||
public void testDoesNotStartElectionIfStopped() {
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode, getLocalPreVoteResponse());
|
||||
startCollector(otherNode).close();
|
||||
runCollector();
|
||||
assertFalse(electionOccurred);
|
||||
}
|
||||
|
||||
public void testIgnoresPreVotesFromLaterTerms() {
|
||||
assumeTrue("unluckily chose lastAcceptedTerm too close to currentTerm, no later terms", lastAcceptedTerm < currentTerm - 1);
|
||||
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode,
|
||||
new PreVoteResponse(currentTerm, randomLongBetween(lastAcceptedTerm + 1, currentTerm - 1), randomNonNegativeLong()));
|
||||
startAndRunCollector(otherNode);
|
||||
assertFalse(electionOccurred);
|
||||
}
|
||||
|
||||
public void testIgnoresPreVotesFromLaterVersionInSameTerm() {
|
||||
assumeTrue("unluckily hit Long.MAX_VALUE for lastAcceptedVersion, cannot increment", lastAcceptedVersion < Long.MAX_VALUE);
|
||||
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode,
|
||||
new PreVoteResponse(currentTerm, lastAcceptedTerm, randomLongBetween(lastAcceptedVersion + 1, Long.MAX_VALUE)));
|
||||
startAndRunCollector(otherNode);
|
||||
assertFalse(electionOccurred);
|
||||
}
|
||||
|
||||
public void testAcceptsPreVotesFromAnyVersionInEarlierTerms() {
|
||||
assumeTrue("unluckily hit 0 for lastAcceptedTerm, cannot decrement", 0 < lastAcceptedTerm);
|
||||
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode,
|
||||
new PreVoteResponse(currentTerm, randomLongBetween(0, lastAcceptedTerm - 1), randomNonNegativeLong()));
|
||||
startAndRunCollector(otherNode);
|
||||
assertTrue(electionOccurred);
|
||||
}
|
||||
|
||||
private PreVoteResponse randomPreVoteResponse() {
|
||||
final long currentTerm = randomNonNegativeLong();
|
||||
return new PreVoteResponse(currentTerm, randomLongBetween(0, currentTerm), randomNonNegativeLong());
|
||||
}
|
||||
|
||||
public void testPrevotingIndicatesElectionSuccess() {
|
||||
assumeTrue("unluckily hit currentTerm = Long.MAX_VALUE, cannot increment", currentTerm < Long.MAX_VALUE);
|
||||
|
||||
final Set<DiscoveryNode> votingNodesSet = new HashSet<>();
|
||||
final int nodeCount = randomIntBetween(0, 5);
|
||||
for (int i = 0; i < nodeCount; i++) {
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node-" + i, buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
responsesByNode.put(otherNode, randomBoolean() ? null : randomPreVoteResponse());
|
||||
PreVoteResponse newPreVoteResponse = new PreVoteResponse(currentTerm, lastAcceptedTerm, lastAcceptedVersion);
|
||||
preVoteCollector.update(newPreVoteResponse, null);
|
||||
if (randomBoolean()) {
|
||||
votingNodesSet.add(otherNode);
|
||||
}
|
||||
}
|
||||
|
||||
DiscoveryNode[] votingNodes = votingNodesSet.toArray(new DiscoveryNode[0]);
|
||||
startAndRunCollector(votingNodes);
|
||||
|
||||
final CoordinationState coordinationState = new CoordinationState(Settings.EMPTY, localNode,
|
||||
new InMemoryPersistedState(currentTerm, makeClusterState(votingNodes)));
|
||||
|
||||
final long newTerm = randomLongBetween(currentTerm + 1, Long.MAX_VALUE);
|
||||
|
||||
coordinationState.handleStartJoin(new StartJoinRequest(localNode, newTerm));
|
||||
|
||||
responsesByNode.forEach((otherNode, preVoteResponse) -> {
|
||||
if (preVoteResponse != null) {
|
||||
try {
|
||||
coordinationState.handleJoin(new Join(otherNode, localNode, newTerm,
|
||||
preVoteResponse.getLastAcceptedTerm(), preVoteResponse.getLastAcceptedVersion()));
|
||||
} catch (CoordinationStateRejectedException ignored) {
|
||||
// ok to reject some joins.
|
||||
}
|
||||
}
|
||||
});
|
||||
|
||||
assertThat(coordinationState.electionWon(), equalTo(electionOccurred));
|
||||
}
|
||||
|
||||
private PreVoteResponse handlePreVoteRequestViaTransportService(PreVoteRequest preVoteRequest) {
|
||||
final AtomicReference<PreVoteResponse> responseRef = new AtomicReference<>();
|
||||
final AtomicReference<TransportException> exceptionRef = new AtomicReference<>();
|
||||
|
||||
transportService.sendRequest(localNode, REQUEST_PRE_VOTE_ACTION_NAME, preVoteRequest,
|
||||
new TransportResponseHandler<PreVoteResponse>() {
|
||||
@Override
|
||||
public void handleResponse(PreVoteResponse response) {
|
||||
responseRef.set(response);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void handleException(TransportException exp) {
|
||||
exceptionRef.set(exp);
|
||||
}
|
||||
|
||||
@Override
|
||||
public String executor() {
|
||||
return SAME;
|
||||
}
|
||||
});
|
||||
|
||||
deterministicTaskQueue.runAllRunnableTasks(random());
|
||||
assertFalse(deterministicTaskQueue.hasDeferredTasks());
|
||||
|
||||
final PreVoteResponse response = responseRef.get();
|
||||
final TransportException transportException = exceptionRef.get();
|
||||
|
||||
if (transportException != null) {
|
||||
assertThat(response, nullValue());
|
||||
throw transportException;
|
||||
}
|
||||
|
||||
assertThat(response, not(nullValue()));
|
||||
return response;
|
||||
}
|
||||
|
||||
public void testResponseIfCandidate() {
|
||||
final long term = randomNonNegativeLong();
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
|
||||
PreVoteResponse newPreVoteResponse = new PreVoteResponse(currentTerm, lastAcceptedTerm, lastAcceptedVersion);
|
||||
preVoteCollector.update(newPreVoteResponse, null);
|
||||
|
||||
assertThat(handlePreVoteRequestViaTransportService(new PreVoteRequest(otherNode, term)), equalTo(newPreVoteResponse));
|
||||
}
|
||||
|
||||
public void testResponseToNonLeaderIfNotCandidate() {
|
||||
final long term = randomNonNegativeLong();
|
||||
final DiscoveryNode leaderNode = new DiscoveryNode("leader-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
final DiscoveryNode otherNode = new DiscoveryNode("other-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
|
||||
PreVoteResponse newPreVoteResponse = new PreVoteResponse(currentTerm, lastAcceptedTerm, lastAcceptedVersion);
|
||||
preVoteCollector.update(newPreVoteResponse, leaderNode);
|
||||
|
||||
RemoteTransportException remoteTransportException = expectThrows(RemoteTransportException.class, () ->
|
||||
handlePreVoteRequestViaTransportService(new PreVoteRequest(otherNode, term)));
|
||||
assertThat(remoteTransportException.getCause(), instanceOf(CoordinationStateRejectedException.class));
|
||||
}
|
||||
|
||||
public void testResponseToRequestFromLeader() {
|
||||
// This is a _rare_ case where our leader has detected a failure and stepped down, but we are still a follower. It's possible that
|
||||
// the leader lost its quorum, but while we're still a follower we will not offer joins to any other node so there is no major
|
||||
// drawback in offering a join to our old leader. The advantage of this is that it makes it slightly more likely that the leader
|
||||
// won't change, and also that its re-election will happen more quickly than if it had to wait for a quorum of followers to also
|
||||
// detect its failure.
|
||||
|
||||
final long term = randomNonNegativeLong();
|
||||
final DiscoveryNode leaderNode = new DiscoveryNode("leader-node", buildNewFakeTransportAddress(), Version.CURRENT);
|
||||
|
||||
PreVoteResponse newPreVoteResponse = new PreVoteResponse(currentTerm, lastAcceptedTerm, lastAcceptedVersion);
|
||||
preVoteCollector.update(newPreVoteResponse, leaderNode);
|
||||
|
||||
assertThat(handlePreVoteRequestViaTransportService(new PreVoteRequest(leaderNode, term)), equalTo(newPreVoteResponse));
|
||||
}
|
||||
}
|
||||
|
|
@ -75,14 +75,13 @@ public class HandshakingTransportAddressConnectorTests extends ESTestCase {
|
|||
super.onSendRequest(requestId, action, request, node);
|
||||
assertThat(action, equalTo(TransportService.HANDSHAKE_ACTION_NAME));
|
||||
assertEquals(remoteNode.getAddress(), node.getAddress());
|
||||
assertNotEquals(remoteNode, node);
|
||||
if (dropHandshake == false) {
|
||||
handleResponse(requestId, new HandshakeResponse(remoteNode, new ClusterName(remoteClusterName), Version.CURRENT));
|
||||
}
|
||||
}
|
||||
};
|
||||
|
||||
transportService = new TransportService(settings, capturingTransport, threadPool,
|
||||
transportService = capturingTransport.createCapturingTransportService(settings, threadPool,
|
||||
TransportService.NOOP_TRANSPORT_INTERCEPTOR, address -> localNode, null, emptySet());
|
||||
|
||||
transportService.start();
|
||||
|
|
|
|||
|
|
@ -33,7 +33,9 @@ import org.elasticsearch.discovery.PeerFinder.TransportAddressConnector;
|
|||
import org.elasticsearch.test.ESTestCase;
|
||||
import org.elasticsearch.test.transport.CapturingTransport;
|
||||
import org.elasticsearch.test.transport.CapturingTransport.CapturedRequest;
|
||||
import org.elasticsearch.test.transport.StubbableConnectionManager;
|
||||
import org.elasticsearch.threadpool.ThreadPool.Names;
|
||||
import org.elasticsearch.transport.ConnectionManager;
|
||||
import org.elasticsearch.transport.TransportException;
|
||||
import org.elasticsearch.transport.TransportResponseHandler;
|
||||
import org.elasticsearch.transport.TransportService;
|
||||
|
|
@ -191,18 +193,20 @@ public class PeerFinderTests extends ESTestCase {
|
|||
deterministicTaskQueue = new DeterministicTaskQueue(settings);
|
||||
|
||||
localNode = newDiscoveryNode("local-node");
|
||||
transportService = new TransportService(settings, capturingTransport,
|
||||
deterministicTaskQueue.getThreadPool(), TransportService.NOOP_TRANSPORT_INTERCEPTOR,
|
||||
boundTransportAddress -> localNode, null, emptySet()) {
|
||||
|
||||
@Override
|
||||
public boolean nodeConnected(DiscoveryNode node) {
|
||||
final boolean isConnected = connectedNodes.contains(node);
|
||||
final boolean isDisconnected = disconnectedNodes.contains(node);
|
||||
assert isConnected != isDisconnected : node + ": isConnected=" + isConnected + ", isDisconnected=" + isDisconnected;
|
||||
ConnectionManager innerConnectionManager
|
||||
= new ConnectionManager(settings, capturingTransport, deterministicTaskQueue.getThreadPool());
|
||||
StubbableConnectionManager connectionManager
|
||||
= new StubbableConnectionManager(innerConnectionManager, settings, capturingTransport, deterministicTaskQueue.getThreadPool());
|
||||
connectionManager.setDefaultNodeConnectedBehavior((cm, discoveryNode) -> {
|
||||
final boolean isConnected = connectedNodes.contains(discoveryNode);
|
||||
final boolean isDisconnected = disconnectedNodes.contains(discoveryNode);
|
||||
assert isConnected != isDisconnected : discoveryNode + ": isConnected=" + isConnected + ", isDisconnected=" + isDisconnected;
|
||||
return isConnected;
|
||||
}
|
||||
};
|
||||
});
|
||||
connectionManager.setDefaultConnectBehavior((cm, discoveryNode) -> capturingTransport.openConnection(discoveryNode, null));
|
||||
transportService = new TransportService(settings, capturingTransport, deterministicTaskQueue.getThreadPool(),
|
||||
TransportService.NOOP_TRANSPORT_INTERCEPTOR, boundTransportAddress -> localNode, null, emptySet(), connectionManager);
|
||||
|
||||
transportService.start();
|
||||
transportService.acceptIncomingRequests();
|
||||
|
|
|
|||
|
|
@ -97,33 +97,7 @@ public class CapturingTransport implements Transport {
|
|||
StubbableConnectionManager connectionManager = new StubbableConnectionManager(new ConnectionManager(settings, this, threadPool),
|
||||
settings, this, threadPool);
|
||||
connectionManager.setDefaultNodeConnectedBehavior((cm, discoveryNode) -> true);
|
||||
connectionManager.setDefaultConnectBehavior((cm, discoveryNode) -> new Connection() {
|
||||
@Override
|
||||
public DiscoveryNode getNode() {
|
||||
return discoveryNode;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void sendRequest(long requestId, String action, TransportRequest request, TransportRequestOptions options)
|
||||
throws TransportException {
|
||||
onSendRequest(requestId, action, request, discoveryNode);
|
||||
}
|
||||
|
||||
@Override
|
||||
public void addCloseListener(ActionListener<Void> listener) {
|
||||
|
||||
}
|
||||
|
||||
@Override
|
||||
public boolean isClosed() {
|
||||
return false;
|
||||
}
|
||||
|
||||
@Override
|
||||
public void close() {
|
||||
|
||||
}
|
||||
});
|
||||
connectionManager.setDefaultConnectBehavior((cm, discoveryNode) -> openConnection(discoveryNode, null));
|
||||
return new TransportService(settings, this, threadPool, interceptor, localNodeFactory, clusterSettings, taskHeaders,
|
||||
connectionManager);
|
||||
|
||||
|
|
|
|||
Loading…
Reference in New Issue