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/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF 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.apache.solr.cloud;
import java.io.Closeable;
import java.io.IOException;
import java.lang.invoke.MethodHandles;
import java.util.ArrayList;
import java.util.EnumSet;
import java.util.List;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.fs.Path;
import org.apache.lucene.search.MatchAllDocsQuery;
import org.apache.solr.cloud.overseer.OverseerAction;
import org.apache.solr.common.SolrException;
import org.apache.solr.common.SolrException.ErrorCode;
import org.apache.solr.common.cloud.ClusterState;
import org.apache.solr.common.cloud.DocCollection;
import org.apache.solr.common.cloud.Replica;
import org.apache.solr.common.cloud.Slice;
import org.apache.solr.common.cloud.SolrZkClient;
import org.apache.solr.common.cloud.ZkCmdExecutor;
import org.apache.solr.common.cloud.ZkCoreNodeProps;
import org.apache.solr.common.cloud.ZkNodeProps;
import org.apache.solr.common.cloud.ZkStateReader;
import org.apache.solr.common.util.RetryUtil;
import org.apache.solr.common.util.Utils;
import org.apache.solr.core.CoreContainer;
import org.apache.solr.core.SolrCore;
import org.apache.solr.logging.MDCLoggingContext;
import org.apache.solr.search.SolrIndexSearcher;
import org.apache.solr.update.PeerSync;
import org.apache.solr.update.UpdateLog;
import org.apache.solr.util.RefCounted;
import org.apache.zookeeper.CreateMode;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NoNodeException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import org.apache.zookeeper.KeeperException.SessionExpiredException;
import org.apache.zookeeper.Op;
import org.apache.zookeeper.OpResult;
import org.apache.zookeeper.OpResult.SetDataResult;
import org.apache.zookeeper.ZooDefs;
import org.apache.zookeeper.data.Stat;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import static org.apache.solr.common.params.CommonParams.ID;
public abstract class ElectionContext implements Closeable {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
final String electionPath;
final ZkNodeProps leaderProps;
final String id;
final String leaderPath;
volatile String leaderSeqPath;
private SolrZkClient zkClient;
public ElectionContext(final String coreNodeName,
final String electionPath, final String leaderPath, final ZkNodeProps leaderProps, final SolrZkClient zkClient) {
assert zkClient != null;
this.id = coreNodeName;
this.electionPath = electionPath;
this.leaderPath = leaderPath;
this.leaderProps = leaderProps;
this.zkClient = zkClient;
}
public void close() {
}
public void cancelElection() throws InterruptedException, KeeperException {
if (leaderSeqPath != null) {
try {
log.debug("Canceling election {}", leaderSeqPath);
zkClient.delete(leaderSeqPath, -1, true);
} catch (NoNodeException e) {
// fine
log.debug("cancelElection did not find election node to remove {}", leaderSeqPath);
}
} else {
log.debug("cancelElection skipped as this context has not been initialized");
}
}
abstract void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs) throws KeeperException, InterruptedException, IOException;
public void checkIfIamLeaderFired() {}
public void joinedElectionFired() {}
public ElectionContext copy(){
throw new UnsupportedOperationException("copy");
}
}
class ShardLeaderElectionContextBase extends ElectionContext {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
protected final SolrZkClient zkClient;
protected String shardId;
protected String collection;
protected LeaderElector leaderElector;
protected ZkStateReader zkStateReader;
protected ZkController zkController;
private Integer leaderZkNodeParentVersion;
// Prevents a race between cancelling and becoming leader.
private final Object lock = new Object();
public ShardLeaderElectionContextBase(LeaderElector leaderElector,
final String shardId, final String collection, final String coreNodeName,
ZkNodeProps props, ZkController zkController) {
super(coreNodeName, ZkStateReader.COLLECTIONS_ZKNODE + "/" + collection
+ "/leader_elect/" + shardId, ZkStateReader.getShardLeadersPath(
collection, shardId), props, zkController.getZkClient());
this.leaderElector = leaderElector;
this.zkStateReader = zkController.getZkStateReader();
this.zkClient = zkStateReader.getZkClient();
this.zkController = zkController;
this.shardId = shardId;
this.collection = collection;
String parent = new Path(leaderPath).getParent().toString();
ZkCmdExecutor zcmd = new ZkCmdExecutor(30000);
// only if /collections/{collection} exists already do we succeed in creating this path
log.info("make sure parent is created {}", parent);
try {
zcmd.ensureExists(parent, (byte[])null, CreateMode.PERSISTENT, zkClient, 2);
} catch (KeeperException e) {
throw new RuntimeException(e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new RuntimeException(e);
}
}
@Override
public void cancelElection() throws InterruptedException, KeeperException {
super.cancelElection();
synchronized (lock) {
if (leaderZkNodeParentVersion != null) {
try {
// We need to be careful and make sure we *only* delete our own leader registration node.
// We do this by using a multi and ensuring the parent znode of the leader registration node
// matches the version we expect - there is a setData call that increments the parent's znode
// version whenever a leader registers.
log.debug("Removing leader registration node on cancel: {} {}", leaderPath, leaderZkNodeParentVersion);
List ops = new ArrayList<>(2);
ops.add(Op.check(new Path(leaderPath).getParent().toString(), leaderZkNodeParentVersion));
ops.add(Op.delete(leaderPath, -1));
zkClient.multi(ops, true);
} catch (KeeperException.NoNodeException nne) {
// no problem
log.debug("No leader registration node found to remove: {}", leaderPath);
} catch (KeeperException.BadVersionException bve) {
log.info("Cannot remove leader registration node because the current registered node is not ours: {}", leaderPath);
// no problem
} catch (InterruptedException e) {
throw e;
} catch (Exception e) {
SolrException.log(log, e);
}
leaderZkNodeParentVersion = null;
} else {
log.info("No version found for ephemeral leader parent node, won't remove previous leader registration.");
}
}
}
@Override
void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs)
throws KeeperException, InterruptedException, IOException {
// register as leader - if an ephemeral is already there, wait to see if it goes away
String parent = new Path(leaderPath).getParent().toString();
try {
RetryUtil.retryOnThrowable(NodeExistsException.class, 60000, 5000, () -> {
synchronized (lock) {
log.info("Creating leader registration node {} after winning as {}", leaderPath, leaderSeqPath);
List ops = new ArrayList<>(2);
// We use a multi operation to get the parent nodes version, which will
// be used to make sure we only remove our own leader registration node.
// The setData call used to get the parent version is also the trigger to
// increment the version. We also do a sanity check that our leaderSeqPath exists.
ops.add(Op.check(leaderSeqPath, -1));
ops.add(Op.create(leaderPath, Utils.toJSON(leaderProps), zkClient.getZkACLProvider().getACLsToAdd(leaderPath), CreateMode.EPHEMERAL));
ops.add(Op.setData(parent, null, -1));
List results;
results = zkClient.multi(ops, true);
for (OpResult result : results) {
if (result.getType() == ZooDefs.OpCode.setData) {
SetDataResult dresult = (SetDataResult) result;
Stat stat = dresult.getStat();
leaderZkNodeParentVersion = stat.getVersion();
return;
}
}
assert leaderZkNodeParentVersion != null;
}
});
} catch (NoNodeException e) {
log.info("Will not register as leader because it seems the election is no longer taking place.");
return;
} catch (Throwable t) {
if (t instanceof OutOfMemoryError) {
throw (OutOfMemoryError) t;
}
throw new SolrException(ErrorCode.SERVER_ERROR, "Could not register as the leader because creating the ephemeral registration node in ZooKeeper failed", t);
}
assert shardId != null;
boolean isAlreadyLeader = false;
if (zkStateReader.getClusterState() != null &&
zkStateReader.getClusterState().getCollection(collection).getSlice(shardId).getReplicas().size() < 2) {
Replica leader = zkStateReader.getLeader(collection, shardId);
if (leader != null
&& leader.getBaseUrl().equals(leaderProps.get(ZkStateReader.BASE_URL_PROP))
&& leader.getCoreName().equals(leaderProps.get(ZkStateReader.CORE_NAME_PROP))) {
isAlreadyLeader = true;
}
}
if (!isAlreadyLeader) {
ZkNodeProps m = ZkNodeProps.fromKeyVals(Overseer.QUEUE_OPERATION, OverseerAction.LEADER.toLower(),
ZkStateReader.SHARD_ID_PROP, shardId,
ZkStateReader.COLLECTION_PROP, collection,
ZkStateReader.BASE_URL_PROP, leaderProps.get(ZkStateReader.BASE_URL_PROP),
ZkStateReader.CORE_NAME_PROP, leaderProps.get(ZkStateReader.CORE_NAME_PROP),
ZkStateReader.STATE_PROP, Replica.State.ACTIVE.toString());
assert zkController != null;
assert zkController.getOverseer() != null;
zkController.getOverseer().offerStateUpdate(Utils.toJSON(m));
}
}
public LeaderElector getLeaderElector() {
return leaderElector;
}
Integer getLeaderZkNodeParentVersion() {
synchronized (lock) {
return leaderZkNodeParentVersion;
}
}
}
// add core container and stop passing core around...
final class ShardLeaderElectionContext extends ShardLeaderElectionContextBase {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
private final CoreContainer cc;
private final SyncStrategy syncStrategy;
private volatile boolean isClosed = false;
public ShardLeaderElectionContext(LeaderElector leaderElector,
final String shardId, final String collection,
final String coreNodeName, ZkNodeProps props, ZkController zkController, CoreContainer cc) {
super(leaderElector, shardId, collection, coreNodeName, props,
zkController);
this.cc = cc;
syncStrategy = new SyncStrategy(cc);
}
@Override
public void close() {
super.close();
this.isClosed = true;
syncStrategy.close();
}
@Override
public void cancelElection() throws InterruptedException, KeeperException {
String coreName = leaderProps.getStr(ZkStateReader.CORE_NAME_PROP);
try (SolrCore core = cc.getCore(coreName)) {
if (core != null) {
core.getCoreDescriptor().getCloudDescriptor().setLeader(false);
}
}
super.cancelElection();
}
@Override
public ElectionContext copy() {
return new ShardLeaderElectionContext(leaderElector, shardId, collection, id, leaderProps, zkController, cc);
}
/*
* weAreReplacement: has someone else been the leader already?
*/
@Override
void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStart) throws KeeperException,
InterruptedException, IOException {
String coreName = leaderProps.getStr(ZkStateReader.CORE_NAME_PROP);
ActionThrottle lt;
try (SolrCore core = cc.getCore(coreName)) {
if (core == null ) {
// shutdown or removed
return;
}
MDCLoggingContext.setCore(core);
lt = core.getUpdateHandler().getSolrCoreState().getLeaderThrottle();
}
try {
lt.minimumWaitBetweenActions();
lt.markAttemptingAction();
int leaderVoteWait = cc.getZkController().getLeaderVoteWait();
log.debug("Running the leader process for shard={} and weAreReplacement={} and leaderVoteWait={}", shardId, weAreReplacement, leaderVoteWait);
if (zkController.getClusterState().getCollection(collection).getSlice(shardId).getReplicas().size() > 1) {
// Clear the leader in clusterstate. We only need to worry about this if there is actually more than one replica.
ZkNodeProps m = new ZkNodeProps(Overseer.QUEUE_OPERATION, OverseerAction.LEADER.toLower(),
ZkStateReader.SHARD_ID_PROP, shardId, ZkStateReader.COLLECTION_PROP, collection);
zkController.getOverseer().getStateUpdateQueue().offer(Utils.toJSON(m));
}
boolean allReplicasInLine = false;
if (!weAreReplacement) {
allReplicasInLine = waitForReplicasToComeUp(leaderVoteWait);
} else {
allReplicasInLine = areAllReplicasParticipating();
}
if (isClosed) {
// Solr is shutting down or the ZooKeeper session expired while waiting for replicas. If the later,
// we cannot be sure we are still the leader, so we should bail out. The OnReconnect handler will
// re-register the cores and handle a new leadership election.
return;
}
Replica.Type replicaType;
String coreNodeName;
boolean setTermToMax = false;
try (SolrCore core = cc.getCore(coreName)) {
if (core == null) {
return;
}
replicaType = core.getCoreDescriptor().getCloudDescriptor().getReplicaType();
coreNodeName = core.getCoreDescriptor().getCloudDescriptor().getCoreNodeName();
// should I be leader?
ZkShardTerms zkShardTerms = zkController.getShardTerms(collection, shardId);
if (zkShardTerms.registered(coreNodeName) && !zkShardTerms.canBecomeLeader(coreNodeName)) {
if (!waitForEligibleBecomeLeaderAfterTimeout(zkShardTerms, coreNodeName, leaderVoteWait)) {
rejoinLeaderElection(core);
return;
} else {
// only log an error if this replica win the election
setTermToMax = true;
}
}
if (isClosed) {
return;
}
log.info("I may be the new leader - try and sync");
// we are going to attempt to be the leader
// first cancel any current recovery
core.getUpdateHandler().getSolrCoreState().cancelRecovery();
if (weAreReplacement) {
// wait a moment for any floating updates to finish
try {
Thread.sleep(2500);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new SolrException(ErrorCode.SERVICE_UNAVAILABLE, e);
}
}
PeerSync.PeerSyncResult result = null;
boolean success = false;
try {
result = syncStrategy.sync(zkController, core, leaderProps, weAreReplacement);
success = result.isSuccess();
} catch (Exception e) {
SolrException.log(log, "Exception while trying to sync", e);
result = PeerSync.PeerSyncResult.failure();
}
UpdateLog ulog = core.getUpdateHandler().getUpdateLog();
if (!success) {
boolean hasRecentUpdates = false;
if (ulog != null) {
// TODO: we could optimize this if necessary
try (UpdateLog.RecentUpdates recentUpdates = ulog.getRecentUpdates()) {
hasRecentUpdates = !recentUpdates.getVersions(1).isEmpty();
}
}
if (!hasRecentUpdates) {
// we failed sync, but we have no versions - we can't sync in that case
// - we were active
// before, so become leader anyway if no one else has any versions either
if (result.getOtherHasVersions().orElse(false)) {
log.info("We failed sync, but we have no versions - we can't sync in that case. But others have some versions, so we should not become leader");
success = false;
} else {
log.info(
"We failed sync, but we have no versions - we can't sync in that case - we were active before, so become leader anyway");
success = true;
}
}
}
// solrcloud_debug
if (log.isDebugEnabled()) {
try {
RefCounted searchHolder = core.getNewestSearcher(false);
SolrIndexSearcher searcher = searchHolder.get();
try {
log.debug(core.getCoreContainer().getZkController().getNodeName() + " synched "
+ searcher.count(new MatchAllDocsQuery()));
} finally {
searchHolder.decref();
}
} catch (Exception e) {
log.error("Error in solrcloud_debug block", e);
}
}
if (!success) {
rejoinLeaderElection(core);
return;
}
}
boolean isLeader = true;
if (!isClosed) {
try {
if (replicaType == Replica.Type.TLOG) {
// stop replicate from old leader
zkController.stopReplicationFromLeader(coreName);
if (weAreReplacement) {
try (SolrCore core = cc.getCore(coreName)) {
Future future = core.getUpdateHandler().getUpdateLog().recoverFromCurrentLog();
if (future != null) {
log.info("Replaying tlog before become new leader");
future.get();
} else {
log.info("New leader does not have old tlog to replay");
}
}
}
}
// in case of leaderVoteWait timeout, a replica with lower term can win the election
if (setTermToMax) {
log.error("WARNING: Potential data loss -- Replica {} became leader after timeout (leaderVoteWait) " +
"without being up-to-date with the previous leader", coreNodeName);
zkController.getShardTerms(collection, shardId).setTermEqualsToLeader(coreNodeName);
}
super.runLeaderProcess(weAreReplacement, 0);
try (SolrCore core = cc.getCore(coreName)) {
if (core != null) {
core.getCoreDescriptor().getCloudDescriptor().setLeader(true);
publishActiveIfRegisteredAndNotActive(core);
} else {
return;
}
}
log.info("I am the new leader: " + ZkCoreNodeProps.getCoreUrl(leaderProps) + " " + shardId);
// we made it as leader - send any recovery requests we need to
syncStrategy.requestRecoveries();
} catch (SessionExpiredException e) {
throw new SolrException(ErrorCode.SERVER_ERROR,
"ZK session expired - cancelling election for " + collection + " " + shardId);
} catch (Exception e) {
isLeader = false;
SolrException.log(log, "There was a problem trying to register as the leader", e);
try (SolrCore core = cc.getCore(coreName)) {
if (core == null) {
log.debug("SolrCore not found:" + coreName + " in " + cc.getLoadedCoreNames());
return;
}
core.getCoreDescriptor().getCloudDescriptor().setLeader(false);
// we could not publish ourselves as leader - try and rejoin election
try {
rejoinLeaderElection(core);
} catch (SessionExpiredException exc) {
throw new SolrException(ErrorCode.SERVER_ERROR,
"ZK session expired - cancelling election for " + collection + " " + shardId);
}
}
}
} else {
cancelElection();
}
} finally {
MDCLoggingContext.clear();
}
}
/**
* Wait for other replicas with higher terms participate in the electioon
* @return true if after {@code timeout} there are no other replicas with higher term participate in the election,
* false if otherwise
*/
private boolean waitForEligibleBecomeLeaderAfterTimeout(ZkShardTerms zkShardTerms, String coreNodeName, int timeout) throws InterruptedException {
long timeoutAt = System.nanoTime() + TimeUnit.NANOSECONDS.convert(timeout, TimeUnit.MILLISECONDS);
while (!isClosed && !cc.isShutDown()) {
if (System.nanoTime() > timeoutAt) {
log.warn("After waiting for {}ms, no other potential leader was found, {} try to become leader anyway (" +
"core_term:{}, highest_term:{})",
timeout, coreNodeName, zkShardTerms.getTerm(coreNodeName), zkShardTerms.getHighestTerm());
return true;
}
if (replicasWithHigherTermParticipated(zkShardTerms, coreNodeName)) {
log.info("Can't become leader, other replicas with higher term participated in leader election");
return false;
}
Thread.sleep(500L);
}
return false;
}
/**
* Do other replicas with higher term participated in the election
* @return true if other replicas with higher term participated in the election, false if otherwise
*/
private boolean replicasWithHigherTermParticipated(ZkShardTerms zkShardTerms, String coreNodeName) {
ClusterState clusterState = zkController.getClusterState();
DocCollection docCollection = clusterState.getCollectionOrNull(collection);
Slice slices = (docCollection == null) ? null : docCollection.getSlice(shardId);
if (slices == null) return false;
long replicaTerm = zkShardTerms.getTerm(coreNodeName);
boolean isRecovering = zkShardTerms.isRecovering(coreNodeName);
for (Replica replica : slices.getReplicas()) {
if (replica.getName().equals(coreNodeName)) continue;
if (clusterState.getLiveNodes().contains(replica.getNodeName())) {
long otherTerm = zkShardTerms.getTerm(replica.getName());
boolean isOtherReplicaRecovering = zkShardTerms.isRecovering(replica.getName());
if (isRecovering && !isOtherReplicaRecovering) return true;
if (otherTerm > replicaTerm) return true;
}
}
return false;
}
public void publishActiveIfRegisteredAndNotActive(SolrCore core) throws Exception {
if (core.getCoreDescriptor().getCloudDescriptor().hasRegistered()) {
ZkStateReader zkStateReader = zkController.getZkStateReader();
zkStateReader.forceUpdateCollection(collection);
ClusterState clusterState = zkStateReader.getClusterState();
Replica rep = getReplica(clusterState, collection, leaderProps.getStr(ZkStateReader.CORE_NODE_NAME_PROP));
if (rep == null) return;
if (rep.getState() != Replica.State.ACTIVE || core.getCoreDescriptor().getCloudDescriptor().getLastPublished() != Replica.State.ACTIVE) {
log.debug("We have become the leader after core registration but are not in an ACTIVE state - publishing ACTIVE");
zkController.publish(core.getCoreDescriptor(), Replica.State.ACTIVE);
}
}
}
private Replica getReplica(ClusterState clusterState, String collectionName, String replicaName) {
if (clusterState == null) return null;
final DocCollection docCollection = clusterState.getCollectionOrNull(collectionName);
if (docCollection == null) return null;
return docCollection.getReplica(replicaName);
}
// returns true if all replicas are found to be up, false if not
private boolean waitForReplicasToComeUp(int timeoutms) throws InterruptedException {
long timeoutAt = System.nanoTime() + TimeUnit.NANOSECONDS.convert(timeoutms, TimeUnit.MILLISECONDS);
final String shardsElectZkPath = electionPath + LeaderElector.ELECTION_NODE;
DocCollection docCollection = zkController.getClusterState().getCollectionOrNull(collection);
Slice slices = (docCollection == null) ? null : docCollection.getSlice(shardId);
int cnt = 0;
while (!isClosed && !cc.isShutDown()) {
// wait for everyone to be up
if (slices != null) {
int found = 0;
try {
found = zkClient.getChildren(shardsElectZkPath, null, true).size();
} catch (KeeperException e) {
if (e instanceof KeeperException.SessionExpiredException) {
// if the session has expired, then another election will be launched, so
// quit here
throw new SolrException(ErrorCode.SERVER_ERROR,
"ZK session expired - cancelling election for " + collection + " " + shardId);
}
SolrException.log(log,
"Error checking for the number of election participants", e);
}
// on startup and after connection timeout, wait for all known shards
if (found >= slices.getReplicas(EnumSet.of(Replica.Type.TLOG, Replica.Type.NRT)).size()) {
log.info("Enough replicas found to continue.");
return true;
} else {
if (cnt % 40 == 0) {
log.info("Waiting until we see more replicas up for shard {}: total={}"
+ " found={}"
+ " timeoutin={}ms",
shardId, slices.getReplicas(EnumSet.of(Replica.Type.TLOG, Replica.Type.NRT)).size(), found,
TimeUnit.MILLISECONDS.convert(timeoutAt - System.nanoTime(), TimeUnit.NANOSECONDS));
}
}
if (System.nanoTime() > timeoutAt) {
log.info("Was waiting for replicas to come up, but they are taking too long - assuming they won't come back till later");
return false;
}
} else {
log.warn("Shard not found: " + shardId + " for collection " + collection);
return false;
}
Thread.sleep(500);
docCollection = zkController.getClusterState().getCollectionOrNull(collection);
slices = (docCollection == null) ? null : docCollection.getSlice(shardId);
cnt++;
}
return false;
}
// returns true if all replicas are found to be up, false if not
private boolean areAllReplicasParticipating() throws InterruptedException {
final String shardsElectZkPath = electionPath + LeaderElector.ELECTION_NODE;
final DocCollection docCollection = zkController.getClusterState().getCollectionOrNull(collection);
if (docCollection != null && docCollection.getSlice(shardId) != null) {
final Slice slices = docCollection.getSlice(shardId);
int found = 0;
try {
found = zkClient.getChildren(shardsElectZkPath, null, true).size();
} catch (KeeperException e) {
if (e instanceof KeeperException.SessionExpiredException) {
// if the session has expired, then another election will be launched, so
// quit here
throw new SolrException(ErrorCode.SERVER_ERROR,
"ZK session expired - cancelling election for " + collection + " " + shardId);
}
SolrException.log(log, "Error checking for the number of election participants", e);
}
if (found >= slices.getReplicasMap().size()) {
log.debug("All replicas are ready to participate in election.");
return true;
}
} else {
log.warn("Shard not found: " + shardId + " for collection " + collection);
return false;
}
return false;
}
private void rejoinLeaderElection(SolrCore core)
throws InterruptedException, KeeperException, IOException {
// remove our ephemeral and re join the election
if (cc.isShutDown()) {
log.debug("Not rejoining election because CoreContainer is closed");
return;
}
log.info("There may be a better leader candidate than us - going back into recovery");
cancelElection();
core.getUpdateHandler().getSolrCoreState().doRecovery(cc, core.getCoreDescriptor());
leaderElector.joinElection(this, true);
}
}
final class OverseerElectionContext extends ElectionContext {
private static final Logger log = LoggerFactory.getLogger(MethodHandles.lookup().lookupClass());
private final SolrZkClient zkClient;
private final Overseer overseer;
private volatile boolean isClosed = false;
public OverseerElectionContext(SolrZkClient zkClient, Overseer overseer, final String zkNodeName) {
super(zkNodeName, Overseer.OVERSEER_ELECT, Overseer.OVERSEER_ELECT + "/leader", null, zkClient);
this.overseer = overseer;
this.zkClient = zkClient;
try {
new ZkCmdExecutor(zkClient.getZkClientTimeout()).ensureExists(Overseer.OVERSEER_ELECT, zkClient);
} catch (KeeperException e) {
throw new SolrException(ErrorCode.SERVER_ERROR, e);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
throw new SolrException(ErrorCode.SERVER_ERROR, e);
}
}
@Override
void runLeaderProcess(boolean weAreReplacement, int pauseBeforeStartMs) throws KeeperException,
InterruptedException {
if (isClosed) {
return;
}
log.info("I am going to be the leader {}", id);
final String id = leaderSeqPath
.substring(leaderSeqPath.lastIndexOf("/") + 1);
ZkNodeProps myProps = new ZkNodeProps(ID, id);
zkClient.makePath(leaderPath, Utils.toJSON(myProps),
CreateMode.EPHEMERAL, true);
if(pauseBeforeStartMs >0){
try {
Thread.sleep(pauseBeforeStartMs);
} catch (InterruptedException e) {
Thread.interrupted();
log.warn("Wait interrupted ", e);
}
}
synchronized (this) {
if (!this.isClosed && !overseer.getZkController().getCoreContainer().isShutDown()) {
overseer.start(id);
}
}
}
@Override
public void cancelElection() throws InterruptedException, KeeperException {
super.cancelElection();
overseer.close();
}
@Override
public synchronized void close() {
this.isClosed = true;
overseer.close();
}
@Override
public ElectionContext copy() {
return new OverseerElectionContext(zkClient, overseer ,id);
}
@Override
public void joinedElectionFired() {
overseer.close();
}
@Override
public void checkIfIamLeaderFired() {
// leader changed - close the overseer
overseer.close();
}
}
