/*
*
* 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.
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package org.apache.hadoop.hbase.replication.regionserver;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Random;
import java.util.SortedMap;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.UUID;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.replication.ReplicationException;
import org.apache.hadoop.hbase.replication.ReplicationListener;
import org.apache.hadoop.hbase.replication.ReplicationPeers;
import org.apache.hadoop.hbase.replication.ReplicationQueues;
import org.apache.hadoop.hbase.replication.ReplicationTracker;
import org.apache.zookeeper.KeeperException;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
/**
* This class is responsible to manage all the replication
* sources. There are two classes of sources:
* <li> Normal sources are persistent and one per peer cluster</li>
* <li> Old sources are recovered from a failed region server and our
* only goal is to finish replicating the HLog queue it had up in ZK</li>
*
* When a region server dies, this class uses a watcher to get notified and it
* tries to grab a lock in order to transfer all the queues in a local
* old source.
*
* This class implements the ReplicationListener interface so that it can track changes in
* replication state.
*/
@InterfaceAudience.Private
public class ReplicationSourceManager implements ReplicationListener {
private static final Log LOG =
LogFactory.getLog(ReplicationSourceManager.class);
// List of all the sources that read this RS's logs
private final List<ReplicationSourceInterface> sources;
// List of all the sources we got from died RSs
private final List<ReplicationSourceInterface> oldsources;
private final ReplicationQueues replicationQueues;
private final ReplicationTracker replicationTracker;
private final ReplicationPeers replicationPeers;
// UUID for this cluster
private final UUID clusterId;
// All about stopping
private final Stoppable stopper;
// All logs we are currently tracking
private final Map<String, SortedSet<String>> hlogsById;
private final Configuration conf;
private final FileSystem fs;
// The path to the latest log we saw, for new coming sources
private Path latestPath;
// Path to the hlogs directories
private final Path logDir;
// Path to the hlog archive
private final Path oldLogDir;
// The number of ms that we wait before moving znodes, HBASE-3596
private final long sleepBeforeFailover;
// Homemade executer service for replication
private final ThreadPoolExecutor executor;
private final Random rand;
/**
* Creates a replication manager and sets the watch on all the other registered region servers
* @param replicationQueues the interface for manipulating replication queues
* @param replicationPeers
* @param replicationTracker
* @param conf the configuration to use
* @param stopper the stopper object for this region server
* @param fs the file system to use
* @param logDir the directory that contains all hlog directories of live RSs
* @param oldLogDir the directory where old logs are archived
* @param clusterId
*/
public ReplicationSourceManager(final ReplicationQueues replicationQueues,
final ReplicationPeers replicationPeers, final ReplicationTracker replicationTracker,
final Configuration conf, final Stoppable stopper, final FileSystem fs, final Path logDir,
final Path oldLogDir, final UUID clusterId) {
this.sources = new ArrayList<ReplicationSourceInterface>();
this.replicationQueues = replicationQueues;
this.replicationPeers = replicationPeers;
this.replicationTracker = replicationTracker;
this.stopper = stopper;
this.hlogsById = new HashMap<String, SortedSet<String>>();
this.oldsources = new ArrayList<ReplicationSourceInterface>();
this.conf = conf;
this.fs = fs;
this.logDir = logDir;
this.oldLogDir = oldLogDir;
this.sleepBeforeFailover = conf.getLong("replication.sleep.before.failover", 2000);
this.clusterId = clusterId;
this.replicationTracker.registerListener(this);
this.replicationPeers.getAllPeerIds();
// It's preferable to failover 1 RS at a time, but with good zk servers
// more could be processed at the same time.
int nbWorkers = conf.getInt("replication.executor.workers", 1);
// use a short 100ms sleep since this could be done inline with a RS startup
// even if we fail, other region servers can take care of it
this.executor = new ThreadPoolExecutor(nbWorkers, nbWorkers,
100, TimeUnit.MILLISECONDS,
new LinkedBlockingQueue<Runnable>());
ThreadFactoryBuilder tfb = new ThreadFactoryBuilder();
tfb.setNameFormat("ReplicationExecutor-%d");
this.executor.setThreadFactory(tfb.build());
this.rand = new Random();
}
/**
* Provide the id of the peer and a log key and this method will figure which
* hlog it belongs to and will log, for this region server, the current
* position. It will also clean old logs from the queue.
* @param log Path to the log currently being replicated from
* replication status in zookeeper. It will also delete older entries.
* @param id id of the peer cluster
* @param position current location in the log
* @param queueRecovered indicates if this queue comes from another region server
* @param holdLogInZK if true then the log is retained in ZK
*/
public void logPositionAndCleanOldLogs(Path log, String id, long position,
boolean queueRecovered, boolean holdLogInZK) {
String fileName = log.getName();
this.replicationQueues.setLogPosition(id, fileName, position);
if (holdLogInZK) {
return;
}
cleanOldLogs(fileName, id, queueRecovered);
}
/**
* Cleans a log file and all older files from ZK. Called when we are sure that a
* log file is closed and has no more entries.
* @param key Path to the log
* @param id id of the peer cluster
* @param queueRecovered Whether this is a recovered queue
*/
public void cleanOldLogs(String key,
String id,
boolean queueRecovered) {
synchronized (this.hlogsById) {
SortedSet<String> hlogs = this.hlogsById.get(id);
if (queueRecovered || hlogs.first().equals(key)) {
return;
}
SortedSet<String> hlogSet = hlogs.headSet(key);
for (String hlog : hlogSet) {
this.replicationQueues.removeLog(id, hlog);
}
hlogSet.clear();
}
}
/**
* Adds a normal source per registered peer cluster and tries to process all
* old region server hlog queues
*/
protected void init() throws IOException, ReplicationException {
for (String id : this.replicationPeers.getConnectedPeers()) {
addSource(id);
}
List<String> currentReplicators = this.replicationQueues.getListOfReplicators();
if (currentReplicators == null || currentReplicators.size() == 0) {
return;
}
List<String> otherRegionServers = replicationTracker.getListOfRegionServers();
LOG.info("Current list of replicators: " + currentReplicators + " other RSs: "
+ otherRegionServers);
// Look if there's anything to process after a restart
for (String rs : currentReplicators) {
if (!otherRegionServers.contains(rs)) {
transferQueues(rs);
}
}
}
/**
* Add a new normal source to this region server
* @param id the id of the peer cluster
* @return the source that was created
* @throws IOException
*/
protected ReplicationSourceInterface addSource(String id) throws IOException,
ReplicationException {
ReplicationSourceInterface src =
getReplicationSource(this.conf, this.fs, this, this.replicationQueues,
this.replicationPeers, stopper, id, this.clusterId);
synchronized (this.hlogsById) {
this.sources.add(src);
this.hlogsById.put(id, new TreeSet<String>());
// Add the latest hlog to that source's queue
if (this.latestPath != null) {
String name = this.latestPath.getName();
this.hlogsById.get(id).add(name);
try {
this.replicationQueues.addLog(src.getPeerClusterZnode(), name);
} catch (ReplicationException e) {
String message =
"Cannot add log to queue when creating a new source, queueId="
+ src.getPeerClusterZnode() + ", filename=" + name;
stopper.stop(message);
throw e;
}
src.enqueueLog(this.latestPath);
}
}
src.startup();
return src;
}
/**
* Delete a complete queue of hlogs associated with a peer cluster
* @param peerId Id of the peer cluster queue of hlogs to delete
*/
public void deleteSource(String peerId, boolean closeConnection) {
this.replicationQueues.removeQueue(peerId);
if (closeConnection) {
this.replicationPeers.disconnectFromPeer(peerId);
}
}
/**
* Terminate the replication on this region server
*/
public void join() {
this.executor.shutdown();
if (this.sources.size() == 0) {
this.replicationQueues.removeAllQueues();
}
for (ReplicationSourceInterface source : this.sources) {
source.terminate("Region server is closing");
}
}
/**
* Get a copy of the hlogs of the first source on this rs
* @return a sorted set of hlog names
*/
protected Map<String, SortedSet<String>> getHLogs() {
return Collections.unmodifiableMap(hlogsById);
}
/**
* Get a list of all the normal sources of this rs
* @return lis of all sources
*/
public List<ReplicationSourceInterface> getSources() {
return this.sources;
}
void preLogRoll(Path newLog) throws IOException {
synchronized (this.hlogsById) {
String name = newLog.getName();
for (ReplicationSourceInterface source : this.sources) {
try {
this.replicationQueues.addLog(source.getPeerClusterZnode(), name);
} catch (ReplicationException e) {
throw new IOException("Cannot add log to replication queue with id="
+ source.getPeerClusterZnode() + ", filename=" + name, e);
}
}
for (SortedSet<String> hlogs : this.hlogsById.values()) {
if (this.sources.isEmpty()) {
// If there's no slaves, don't need to keep the old hlogs since
// we only consider the last one when a new slave comes in
hlogs.clear();
}
hlogs.add(name);
}
}
this.latestPath = newLog;
}
void postLogRoll(Path newLog) throws IOException {
// This only updates the sources we own, not the recovered ones
for (ReplicationSourceInterface source : this.sources) {
source.enqueueLog(newLog);
}
}
/**
* Factory method to create a replication source
* @param conf the configuration to use
* @param fs the file system to use
* @param manager the manager to use
* @param stopper the stopper object for this region server
* @param peerId the id of the peer cluster
* @return the created source
* @throws IOException
*/
protected ReplicationSourceInterface getReplicationSource(final Configuration conf,
final FileSystem fs, final ReplicationSourceManager manager,
final ReplicationQueues replicationQueues, final ReplicationPeers replicationPeers,
final Stoppable stopper, final String peerId, final UUID clusterId) throws IOException {
ReplicationSourceInterface src;
try {
@SuppressWarnings("rawtypes")
Class c = Class.forName(conf.get("replication.replicationsource.implementation",
ReplicationSource.class.getCanonicalName()));
src = (ReplicationSourceInterface) c.newInstance();
} catch (Exception e) {
LOG.warn("Passed replication source implementation throws errors, " +
"defaulting to ReplicationSource", e);
src = new ReplicationSource();
}
src.init(conf, fs, manager, replicationQueues, replicationPeers, stopper, peerId, clusterId);
return src;
}
/**
* Transfer all the queues of the specified to this region server.
* First it tries to grab a lock and if it works it will move the
* znodes and finally will delete the old znodes.
*
* It creates one old source for any type of source of the old rs.
* @param rsZnode
*/
private void transferQueues(String rsZnode) {
NodeFailoverWorker transfer =
new NodeFailoverWorker(rsZnode, this.replicationQueues, this.replicationPeers,
this.clusterId);
try {
this.executor.execute(transfer);
} catch (RejectedExecutionException ex) {
LOG.info("Cancelling the transfer of " + rsZnode + " because of " + ex.getMessage());
}
}
/**
* Clear the references to the specified old source
* @param src source to clear
*/
public void closeRecoveredQueue(ReplicationSourceInterface src) {
LOG.info("Done with the recovered queue " + src.getPeerClusterZnode());
this.oldsources.remove(src);
deleteSource(src.getPeerClusterZnode(), false);
}
/**
* Thie method first deletes all the recovered sources for the specified
* id, then deletes the normal source (deleting all related data in ZK).
* @param id The id of the peer cluster
*/
public void removePeer(String id) {
LOG.info("Closing the following queue " + id + ", currently have "
+ sources.size() + " and another "
+ oldsources.size() + " that were recovered");
String terminateMessage = "Replication stream was removed by a user";
ReplicationSourceInterface srcToRemove = null;
List<ReplicationSourceInterface> oldSourcesToDelete =
new ArrayList<ReplicationSourceInterface>();
// First close all the recovered sources for this peer
for (ReplicationSourceInterface src : oldsources) {
if (id.equals(src.getPeerClusterId())) {
oldSourcesToDelete.add(src);
}
}
for (ReplicationSourceInterface src : oldSourcesToDelete) {
src.terminate(terminateMessage);
closeRecoveredQueue((src));
}
LOG.info("Number of deleted recovered sources for " + id + ": "
+ oldSourcesToDelete.size());
// Now look for the one on this cluster
for (ReplicationSourceInterface src : this.sources) {
if (id.equals(src.getPeerClusterId())) {
srcToRemove = src;
break;
}
}
if (srcToRemove == null) {
LOG.error("The queue we wanted to close is missing " + id);
return;
}
srcToRemove.terminate(terminateMessage);
this.sources.remove(srcToRemove);
deleteSource(id, true);
}
@Override
public void regionServerRemoved(String regionserver) {
transferQueues(regionserver);
}
@Override
public void peerRemoved(String peerId) {
removePeer(peerId);
}
@Override
public void peerListChanged(List<String> peerIds) {
for (String id : peerIds) {
try {
boolean added = this.replicationPeers.connectToPeer(id);
if (added) {
addSource(id);
}
} catch (Exception e) {
LOG.error("Error while adding a new peer", e);
}
}
}
/**
* Class responsible to setup new ReplicationSources to take care of the
* queues from dead region servers.
*/
class NodeFailoverWorker extends Thread {
private String rsZnode;
private final ReplicationQueues rq;
private final ReplicationPeers rp;
private final UUID clusterId;
/**
*
* @param rsZnode
*/
public NodeFailoverWorker(String rsZnode, final ReplicationQueues replicationQueues,
final ReplicationPeers replicationPeers, final UUID clusterId) {
super("Failover-for-"+rsZnode);
this.rsZnode = rsZnode;
this.rq = replicationQueues;
this.rp = replicationPeers;
this.clusterId = clusterId;
}
@Override
public void run() {
// Wait a bit before transferring the queues, we may be shutting down.
// This sleep may not be enough in some cases.
try {
Thread.sleep(sleepBeforeFailover + (long) (rand.nextFloat() * sleepBeforeFailover));
} catch (InterruptedException e) {
LOG.warn("Interrupted while waiting before transferring a queue.");
Thread.currentThread().interrupt();
}
// We try to lock that rs' queue directory
if (stopper.isStopped()) {
LOG.info("Not transferring queue since we are shutting down");
return;
}
SortedMap<String, SortedSet<String>> newQueues = null;
newQueues = this.rq.claimQueues(rsZnode);
// Copying over the failed queue is completed.
if (newQueues.isEmpty()) {
// We either didn't get the lock or the failed region server didn't have any outstanding
// HLogs to replicate, so we are done.
return;
}
for (Map.Entry<String, SortedSet<String>> entry : newQueues.entrySet()) {
String peerId = entry.getKey();
try {
ReplicationSourceInterface src =
getReplicationSource(conf, fs, ReplicationSourceManager.this, this.rq, this.rp,
stopper, peerId, this.clusterId);
if (!this.rp.getConnectedPeers().contains((src.getPeerClusterId()))) {
src.terminate("Recovered queue doesn't belong to any current peer");
break;
}
oldsources.add(src);
for (String hlog : entry.getValue()) {
src.enqueueLog(new Path(oldLogDir, hlog));
}
src.startup();
} catch (IOException e) {
// TODO manage it
LOG.error("Failed creating a source", e);
}
}
}
}
/**
* Get the directory where hlogs are archived
* @return the directory where hlogs are archived
*/
public Path getOldLogDir() {
return this.oldLogDir;
}
/**
* Get the directory where hlogs are stored by their RSs
* @return the directory where hlogs are stored by their RSs
*/
public Path getLogDir() {
return this.logDir;
}
/**
* Get the handle on the local file system
* @return Handle on the local file system
*/
public FileSystem getFs() {
return this.fs;
}
/**
* Get a string representation of all the sources' metrics
*/
public String getStats() {
StringBuffer stats = new StringBuffer();
for (ReplicationSourceInterface source : sources) {
stats.append("Normal source for cluster " + source.getPeerClusterId() + ": ");
stats.append(source.getStats() + "\n");
}
for (ReplicationSourceInterface oldSource : oldsources) {
stats.append("Recovered source for cluster/machine(s) " + oldSource.getPeerClusterId() + ": ");
stats.append(oldSource.getStats()+ "\n");
}
return stats.toString();
}
}