/**
* Copyright 2010 The Apache Software Foundation
*
* 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.hadoop.hbase.master;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.lang.Thread.UncaughtExceptionHandler;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Date;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.NavigableMap;
import java.util.Set;
import java.util.SortedMap;
import java.util.TreeMap;
import java.util.TreeSet;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.Chore;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.HRegionInfo;
import org.apache.hadoop.hbase.NotServingRegionException;
import org.apache.hadoop.hbase.Server;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.Stoppable;
import org.apache.hadoop.hbase.TableNotFoundException;
import org.apache.hadoop.hbase.catalog.CatalogTracker;
import org.apache.hadoop.hbase.catalog.MetaReader;
import org.apache.hadoop.hbase.catalog.RootLocationEditor;
import org.apache.hadoop.hbase.client.Result;
import org.apache.hadoop.hbase.executor.ExecutorService;
import org.apache.hadoop.hbase.executor.RegionTransitionData;
import org.apache.hadoop.hbase.ipc.ServerNotRunningYetException;
import org.apache.hadoop.hbase.master.AssignmentManager.RegionState;
import org.apache.hadoop.hbase.executor.EventHandler.EventType;
import org.apache.hadoop.hbase.regionserver.RegionAlreadyInTransitionException;
import org.apache.hadoop.hbase.regionserver.RegionOpeningState;
import org.apache.hadoop.hbase.master.RegionPlan;
import org.apache.hadoop.hbase.master.handler.ClosedRegionHandler;
import org.apache.hadoop.hbase.master.handler.DisableTableHandler;
import org.apache.hadoop.hbase.master.handler.EnableTableHandler;
import org.apache.hadoop.hbase.master.handler.OpenedRegionHandler;
import org.apache.hadoop.hbase.master.handler.ServerShutdownHandler;
import org.apache.hadoop.hbase.master.handler.SplitRegionHandler;
import org.apache.hadoop.hbase.regionserver.RegionServerStoppedException;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.Pair;
import org.apache.hadoop.hbase.util.Threads;
import org.apache.hadoop.hbase.util.Writables;
import org.apache.hadoop.hbase.zookeeper.ZKAssign;
import org.apache.hadoop.hbase.zookeeper.ZKTable;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.hadoop.hbase.zookeeper.ZooKeeperListener;
import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.zookeeper.AsyncCallback;
import org.apache.zookeeper.KeeperException;
import org.apache.zookeeper.KeeperException.NodeExistsException;
import org.apache.zookeeper.data.Stat;
/**
* Manages and performs region assignment.
* <p>
* Monitors ZooKeeper for events related to regions in transition.
* <p>
* Handles existing regions in transition during master failover.
*/
public class AssignmentManager extends ZooKeeperListener {
private static final Log LOG = LogFactory.getLog(AssignmentManager.class);
protected Server master;
private ServerManager serverManager;
private CatalogTracker catalogTracker;
private TimeoutMonitor timeoutMonitor;
private LoadBalancer balancer;
/**
* Map of regions to reopen after the schema of a table is changed. Key -
* encoded region name, value - HRegionInfo
*/
private final Map <String, HRegionInfo> regionsToReopen;
/*
* Maximum times we recurse an assignment. See below in {@link #assign()}.
*/
private final int maximumAssignmentAttempts;
/**
* Regions currently in transition. Map of encoded region names to the master
* in-memory state for that region.
*/
final ConcurrentSkipListMap<String, RegionState> regionsInTransition =
new ConcurrentSkipListMap<String, RegionState>();
/** Plans for region movement. Key is the encoded version of a region name*/
// TODO: When do plans get cleaned out? Ever? In server open and in server
// shutdown processing -- St.Ack
// All access to this Map must be synchronized.
final NavigableMap<String, RegionPlan> regionPlans =
new TreeMap<String, RegionPlan>();
private final ZKTable zkTable;
// store all the table names in disabling state
Set<String> disablingTables = new HashSet<String>(1);
// store all the enabling state tablenames.
Set<String> enablingTables = new HashSet<String>(1);
/**
* Server to regions assignment map.
* Contains the set of regions currently assigned to a given server.
* This Map and {@link #regions} are tied. Always update this in tandem
* with the other under a lock on {@link #regions}
* @see #regions
*/
private final NavigableMap<ServerName, Set<HRegionInfo>> servers =
new TreeMap<ServerName, Set<HRegionInfo>>();
/**
* Region to server assignment map.
* Contains the server a given region is currently assigned to.
* This Map and {@link #servers} are tied. Always update this in tandem
* with the other under a lock on {@link #regions}
* @see #servers
*/
private final SortedMap<HRegionInfo, ServerName> regions =
new TreeMap<HRegionInfo, ServerName>();
private final ExecutorService executorService;
//Thread pool executor service for timeout monitor
private java.util.concurrent.ExecutorService threadPoolExecutorService;
private List<EventType> ignoreStatesRSOffline = Arrays.asList(new EventType[]{
EventType.RS_ZK_REGION_FAILED_OPEN, EventType.RS_ZK_REGION_CLOSED });
/**
* Constructs a new assignment manager.
*
* @param master
* @param serverManager
* @param catalogTracker
* @param service
* @throws KeeperException
* @throws IOException
*/
public AssignmentManager(Server master, ServerManager serverManager,
CatalogTracker catalogTracker, final ExecutorService service)
throws KeeperException, IOException {
super(master.getZooKeeper());
this.master = master;
this.serverManager = serverManager;
this.catalogTracker = catalogTracker;
this.executorService = service;
this.regionsToReopen = Collections.synchronizedMap
(new HashMap<String, HRegionInfo> ());
Configuration conf = master.getConfiguration();
this.timeoutMonitor = new TimeoutMonitor(
conf.getInt("hbase.master.assignment.timeoutmonitor.period", 10000),
master, serverManager,
conf.getInt("hbase.master.assignment.timeoutmonitor.timeout", 1800000));
Threads.setDaemonThreadRunning(timeoutMonitor.getThread(),
master.getServerName() + ".timeoutMonitor");
this.zkTable = new ZKTable(this.master.getZooKeeper());
this.maximumAssignmentAttempts =
this.master.getConfiguration().getInt("hbase.assignment.maximum.attempts", 10);
this.balancer = LoadBalancerFactory.getLoadBalancer(conf);
this.threadPoolExecutorService = Executors.newCachedThreadPool();
}
/**
* Compute the average load across all region servers.
* Currently, this uses a very naive computation - just uses the number of
* regions being served, ignoring stats about number of requests.
* @return the average load
*/
double getAverageLoad() {
int totalLoad = 0;
int numServers = 0;
// Sync on this.regions because access to this.servers always synchronizes
// in this order.
synchronized (this.regions) {
for (Map.Entry<ServerName, Set<HRegionInfo>> e: servers.entrySet()) {
numServers++;
totalLoad += e.getValue().size();
}
}
return (double)totalLoad / (double)numServers;
}
/**
* @return Instance of ZKTable.
*/
public ZKTable getZKTable() {
// These are 'expensive' to make involving trip to zk ensemble so allow
// sharing.
return this.zkTable;
}
/**
* Returns the RegionServer to which hri is assigned.
*
* @param hri
* HRegion for which this function returns the region server
* @return HServerInfo The region server to which hri belongs
*/
public ServerName getRegionServerOfRegion(HRegionInfo hri) {
synchronized (this.regions ) {
return regions.get(hri);
}
}
/**
* Add a regionPlan for the specified region.
* @param encodedName
* @param plan
*/
public void addPlan(String encodedName, RegionPlan plan) {
synchronized (regionPlans) {
regionPlans.put(encodedName, plan);
}
}
/**
* Set the list of regions that will be reopened
* because of an update in table schema
*
* @param regions
* list of regions that should be tracked for reopen
*/
public void setRegionsToReopen(List <HRegionInfo> regions) {
for(HRegionInfo hri : regions) {
regionsToReopen.put(hri.getEncodedName(), hri);
}
}
/**
* Used by the client to identify if all regions have the schema updates
*
* @param tableName
* @return Pair indicating the status of the alter command
* @throws IOException
* @throws InterruptedException
*/
public Pair<Integer, Integer> getReopenStatus(byte[] tableName)
throws IOException, InterruptedException {
List <HRegionInfo> hris =
MetaReader.getTableRegions(this.master.getCatalogTracker(), tableName);
Integer pending = 0;
for(HRegionInfo hri : hris) {
if(regionsToReopen.get(hri.getEncodedName()) != null) {
pending++;
}
}
return new Pair<Integer, Integer>(pending, hris.size());
}
/**
* Reset all unassigned znodes. Called on startup of master.
* Call {@link #assignAllUserRegions()} after root and meta have been assigned.
* @throws IOException
* @throws KeeperException
*/
void cleanoutUnassigned() throws IOException, KeeperException {
// Cleanup any existing ZK nodes and start watching
ZKAssign.deleteAllNodes(watcher);
ZKUtil.listChildrenAndWatchForNewChildren(this.watcher,
this.watcher.assignmentZNode);
}
/**
* Called on startup.
* Figures whether a fresh cluster start of we are joining extant running cluster.
* @throws IOException
* @throws KeeperException
* @throws InterruptedException
*/
void joinCluster() throws IOException, KeeperException, InterruptedException {
// Concurrency note: In the below the accesses on regionsInTransition are
// outside of a synchronization block where usually all accesses to RIT are
// synchronized. The presumption is that in this case it is safe since this
// method is being played by a single thread on startup.
// TODO: Regions that have a null location and are not in regionsInTransitions
// need to be handled.
// Scan META to build list of existing regions, servers, and assignment
// Returns servers who have not checked in (assumed dead) and their regions
Map<ServerName,List<Pair<HRegionInfo,Result>>> deadServers =
rebuildUserRegions();
processDeadServersAndRegionsInTransition(deadServers);
// Recover the tables that were not fully moved to DISABLED state.
// These tables are in DISABLING state when the master restarted/switched.
boolean isWatcherCreated = recoverTableInDisablingState(this.disablingTables);
recoverTableInEnablingState(this.enablingTables, isWatcherCreated);
}
/**
* Process all regions that are in transition up in zookeeper. Used by
* master joining an already running cluster.
* @throws KeeperException
* @throws IOException
* @throws InterruptedException
*/
void processDeadServersAndRegionsInTransition()
throws KeeperException, IOException, InterruptedException {
// Pass null to signify no dead servers in this context.
processDeadServersAndRegionsInTransition(null);
}
/**
* Process all regions that are in transition in zookeeper and also
* processes the list of dead servers by scanning the META.
* Used by master joining an cluster.
* @param deadServers
* Map of dead servers and their regions. Can be null.
* @throws KeeperException
* @throws IOException
* @throws InterruptedException
*/
void processDeadServersAndRegionsInTransition(
final Map<ServerName, List<Pair<HRegionInfo, Result>>> deadServers)
throws KeeperException, IOException, InterruptedException {
List<String> nodes = ZKUtil.listChildrenAndWatchForNewChildren(watcher,
watcher.assignmentZNode);
// Run through all regions. If they are not assigned and not in RIT, then
// its a clean cluster startup, else its a failover.
boolean regionsToProcess = false;
for (Map.Entry<HRegionInfo, ServerName> e: this.regions.entrySet()) {
if (!e.getKey().isMetaTable()
&& e.getValue() != null) {
LOG.debug("Found " + e + " out on cluster");
regionsToProcess = true;
break;
}
if (nodes.contains(e.getKey().getEncodedName())) {
LOG.debug("Found " + e.getKey().getRegionNameAsString() + " in RITs");
// Could be a meta region.
regionsToProcess = true;
break;
}
}
// If we found user regions out on cluster, its a failover.
if (regionsToProcess) {
LOG.info("Found regions out on cluster or in RIT; failover");
// Process list of dead servers and regions in RIT.
// See HBASE-4580 for more information.
processDeadServersAndRecoverLostRegions(deadServers, nodes);
} else {
// Fresh cluster startup.
LOG.info("Clean cluster startup. Assigning userregions");
cleanoutUnassigned();
assignAllUserRegions();
}
}
/**
* If region is up in zk in transition, then do fixup and block and wait until
* the region is assigned and out of transition. Used on startup for
* catalog regions.
* @param hri Region to look for.
* @return True if we processed a region in transition else false if region
* was not up in zk in transition.
* @throws InterruptedException
* @throws KeeperException
* @throws IOException
*/
boolean processRegionInTransitionAndBlockUntilAssigned(final HRegionInfo hri)
throws InterruptedException, KeeperException, IOException {
boolean intransistion =
processRegionInTransition(hri.getEncodedName(), hri, null);
if (!intransistion) return intransistion;
LOG.debug("Waiting on " + HRegionInfo.prettyPrint(hri.getEncodedName()));
synchronized(this.regionsInTransition) {
while (!this.master.isStopped() &&
this.regionsInTransition.containsKey(hri.getEncodedName())) {
this.regionsInTransition.wait();
}
}
return intransistion;
}
/**
* Process failover of new master for region <code>encodedRegionName</code>
* up in zookeeper.
* @param encodedRegionName Region to process failover for.
* @param regionInfo If null we'll go get it from meta table.
* @param deadServers Can be null
* @return True if we processed <code>regionInfo</code> as a RIT.
* @throws KeeperException
* @throws IOException
*/
boolean processRegionInTransition(final String encodedRegionName,
final HRegionInfo regionInfo,
final Map<ServerName,List<Pair<HRegionInfo,Result>>> deadServers)
throws KeeperException, IOException {
Stat stat = new Stat();
RegionTransitionData data = ZKAssign.getDataAndWatch(watcher,
encodedRegionName, stat);
if (data == null) return false;
HRegionInfo hri = regionInfo;
if (hri == null) {
Pair<HRegionInfo, ServerName> p =
MetaReader.getRegion(catalogTracker, data.getRegionName());
if (p == null) return false;
hri = p.getFirst();
}
processRegionsInTransition(data, hri, deadServers, stat.getVersion());
return true;
}
void processRegionsInTransition(final RegionTransitionData data,
final HRegionInfo regionInfo,
final Map<ServerName, List<Pair<HRegionInfo, Result>>> deadServers,
int expectedVersion)
throws KeeperException {
String encodedRegionName = regionInfo.getEncodedName();
LOG.info("Processing region " + regionInfo.getRegionNameAsString() +
" in state " + data.getEventType());
synchronized (regionsInTransition) {
switch (data.getEventType()) {
case M_ZK_REGION_CLOSING:
// If zk node of the region was updated by a live server skip this
// region and just add it into RIT.
if (isOnDeadServer(regionInfo, deadServers) &&
(data.getOrigin() == null || !serverManager.isServerOnline(data.getOrigin()))) {
// If was on dead server, its closed now. Force to OFFLINE and this
// will get it reassigned if appropriate
forceOffline(regionInfo, data);
} else {
// Just insert region into RIT.
// If this never updates the timeout will trigger new assignment
regionsInTransition.put(encodedRegionName, new RegionState(
regionInfo, RegionState.State.CLOSING,
data.getStamp(), data.getOrigin()));
}
break;
case RS_ZK_REGION_CLOSED:
case RS_ZK_REGION_FAILED_OPEN:
// Region is closed, insert into RIT and handle it
addToRITandCallClose(regionInfo, RegionState.State.CLOSED, data);
break;
case M_ZK_REGION_OFFLINE:
// Region is offline, insert into RIT and handle it like a closed
addToRITandCallClose(regionInfo, RegionState.State.OFFLINE, data);
break;
case RS_ZK_REGION_OPENING:
// TODO: Could check if it was on deadServers. If it was, then we could
// do what happens in TimeoutMonitor when it sees this condition.
// Just insert region into RIT
// If this never updates the timeout will trigger new assignment
if (regionInfo.isMetaTable()) {
regionsInTransition.put(encodedRegionName, new RegionState(
regionInfo, RegionState.State.OPENING, data.getStamp(), data
.getOrigin()));
// If ROOT or .META. table is waiting for timeout monitor to assign
// it may take lot of time when the assignment.timeout.period is
// the default value which may be very long. We will not be able
// to serve any request during this time.
// So we will assign the ROOT and .META. region immediately.
processOpeningState(regionInfo);
break;
}
regionsInTransition.put(encodedRegionName, new RegionState(regionInfo,
RegionState.State.OPENING, data.getStamp(), data.getOrigin()));
break;
case RS_ZK_REGION_OPENED:
// Region is opened, insert into RIT and handle it
regionsInTransition.put(encodedRegionName, new RegionState(
regionInfo, RegionState.State.OPEN,
data.getStamp(), data.getOrigin()));
ServerName sn = data.getOrigin() == null? null: data.getOrigin();
// sn could be null if this server is no longer online. If
// that is the case, just let this RIT timeout; it'll be assigned
// to new server then.
if (sn == null) {
LOG.warn("Region in transition " + regionInfo.getEncodedName() +
" references a null server; letting RIT timeout so will be " +
"assigned elsewhere");
} else if (!serverManager.isServerOnline(sn)
&& (isOnDeadServer(regionInfo, deadServers)
|| regionInfo.isMetaRegion() || regionInfo.isRootRegion())) {
forceOffline(regionInfo, data);
} else {
new OpenedRegionHandler(master, this, regionInfo, sn, expectedVersion)
.process();
}
break;
}
}
}
/**
* Put the region <code>hri</code> into an offline state up in zk.
* @param hri
* @param oldData
* @throws KeeperException
*/
private void forceOffline(final HRegionInfo hri,
final RegionTransitionData oldData)
throws KeeperException {
// If was on dead server, its closed now. Force to OFFLINE and then
// handle it like a close; this will get it reassigned if appropriate
LOG.debug("RIT " + hri.getEncodedName() + " in state=" +
oldData.getEventType() + " was on deadserver; forcing offline");
ZKAssign.createOrForceNodeOffline(this.watcher, hri,
this.master.getServerName());
addToRITandCallClose(hri, RegionState.State.OFFLINE, oldData);
}
/**
* Add to the in-memory copy of regions in transition and then call close
* handler on passed region <code>hri</code>
* @param hri
* @param state
* @param oldData
*/
private void addToRITandCallClose(final HRegionInfo hri,
final RegionState.State state, final RegionTransitionData oldData) {
this.regionsInTransition.put(hri.getEncodedName(),
new RegionState(hri, state, oldData.getStamp(), oldData.getOrigin()));
new ClosedRegionHandler(this.master, this, hri).process();
}
/**
* When a region is closed, it should be removed from the regionsToReopen
* @param hri HRegionInfo of the region which was closed
*/
public void removeClosedRegion(HRegionInfo hri) {
if (!regionsToReopen.isEmpty()) {
if (regionsToReopen.remove(hri.getEncodedName()) != null) {
LOG.debug("Removed region from reopening regions because it was closed");
}
}
}
/**
* @param regionInfo
* @param deadServers Map of deadServers and the regions they were carrying;
* can be null.
* @return True if the passed regionInfo in the passed map of deadServers?
*/
private boolean isOnDeadServer(final HRegionInfo regionInfo,
final Map<ServerName, List<Pair<HRegionInfo, Result>>> deadServers) {
if (deadServers == null) return false;
for (Map.Entry<ServerName, List<Pair<HRegionInfo, Result>>> deadServer:
deadServers.entrySet()) {
for (Pair<HRegionInfo, Result> e: deadServer.getValue()) {
if (e.getFirst().equals(regionInfo)) return true;
}
}
return false;
}
/**
* Handles various states an unassigned node can be in.
* <p>
* Method is called when a state change is suspected for an unassigned node.
* <p>
* This deals with skipped transitions (we got a CLOSED but didn't see CLOSING
* yet).
* @param data
* @param expectedVersion
*/
private void handleRegion(final RegionTransitionData data, int expectedVersion) {
synchronized(regionsInTransition) {
if (data == null || data.getOrigin() == null) {
LOG.warn("Unexpected NULL input " + data);
return;
}
ServerName sn = data.getOrigin();
// Check if this is a special HBCK transition
if (sn.equals(HConstants.HBCK_CODE_SERVERNAME)) {
handleHBCK(data);
return;
}
String encodedName = HRegionInfo.encodeRegionName(data.getRegionName());
String prettyPrintedRegionName = HRegionInfo.prettyPrint(encodedName);
// Verify this is a known server
if (!serverManager.isServerOnline(sn) &&
!this.master.getServerName().equals(sn)
&& !ignoreStatesRSOffline.contains(data.getEventType())) {
LOG.warn("Attempted to handle region transition for server but " +
"server is not online: " + prettyPrintedRegionName);
return;
}
// Printing if the event was created a long time ago helps debugging
boolean lateEvent = data.getStamp() <
(System.currentTimeMillis() - 15000);
LOG.debug("Handling transition=" + data.getEventType() +
", server=" + data.getOrigin() + ", region=" +
(prettyPrintedRegionName == null? "null": prettyPrintedRegionName) +
(lateEvent? ", which is more than 15 seconds late" : ""));
RegionState regionState = regionsInTransition.get(encodedName);
switch (data.getEventType()) {
case M_ZK_REGION_OFFLINE:
// Nothing to do.
break;
case RS_ZK_REGION_SPLITTING:
if (!isInStateForSplitting(regionState)) break;
addSplittingToRIT(sn, encodedName);
break;
case RS_ZK_REGION_SPLIT:
// RegionState must be null, or SPLITTING or PENDING_CLOSE.
if (!isInStateForSplitting(regionState)) break;
// If null, add SPLITTING state before going to SPLIT
if (regionState == null) {
regionState = addSplittingToRIT(sn, encodedName);
String message = "Received SPLIT for region " + prettyPrintedRegionName +
" from server " + sn;
// If still null, it means we cannot find it and it was already processed
if (regionState == null) {
LOG.warn(message + " but it doesn't exist anymore," +
" probably already processed its split");
break;
}
LOG.info(message +
" but region was not first in SPLITTING state; continuing");
}
// Check it has daughters.
byte [] payload = data.getPayload();
List<HRegionInfo> daughters = null;
try {
daughters = Writables.getHRegionInfos(payload, 0, payload.length);
} catch (IOException e) {
LOG.error("Dropped split! Failed reading split payload for " +
prettyPrintedRegionName);
break;
}
assert daughters.size() == 2;
// Assert that we can get a serverinfo for this server.
if (!this.serverManager.isServerOnline(sn)) {
LOG.error("Dropped split! ServerName=" + sn + " unknown.");
break;
}
// Run handler to do the rest of the SPLIT handling.
this.executorService.submit(new SplitRegionHandler(master, this,
regionState.getRegion(), sn, daughters));
break;
case M_ZK_REGION_CLOSING:
// Should see CLOSING after we have asked it to CLOSE or additional
// times after already being in state of CLOSING
if (regionState == null ||
(!regionState.isPendingClose() && !regionState.isClosing())) {
LOG.warn("Received CLOSING for region " + prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not " +
"in expected PENDING_CLOSE or CLOSING states");
return;
}
// Transition to CLOSING (or update stamp if already CLOSING)
regionState.update(RegionState.State.CLOSING,
data.getStamp(), data.getOrigin());
break;
case RS_ZK_REGION_CLOSED:
// Should see CLOSED after CLOSING but possible after PENDING_CLOSE
if (regionState == null ||
(!regionState.isPendingClose() && !regionState.isClosing())) {
LOG.warn("Received CLOSED for region " + prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not " +
"in expected PENDING_CLOSE or CLOSING states");
return;
}
// Handle CLOSED by assigning elsewhere or stopping if a disable
// If we got here all is good. Need to update RegionState -- else
// what follows will fail because not in expected state.
regionState.update(RegionState.State.CLOSED,
data.getStamp(), data.getOrigin());
removeClosedRegion(regionState.getRegion());
this.executorService.submit(new ClosedRegionHandler(master,
this, regionState.getRegion()));
break;
case RS_ZK_REGION_FAILED_OPEN:
if (regionState == null ||
(!regionState.isPendingOpen() && !regionState.isOpening())) {
LOG.warn("Received FAILED_OPEN for region " + prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not in PENDING_OPEN or OPENING");
return;
}
// Handle this the same as if it were opened and then closed.
regionState.update(RegionState.State.CLOSED,
data.getStamp(), data.getOrigin());
this.executorService.submit(new ClosedRegionHandler(master,
this, regionState.getRegion()));
break;
case RS_ZK_REGION_OPENING:
// Should see OPENING after we have asked it to OPEN or additional
// times after already being in state of OPENING
if (regionState == null ||
(!regionState.isPendingOpen() && !regionState.isOpening())) {
LOG.warn("Received OPENING for region " +
prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not " +
"in expected PENDING_OPEN or OPENING states");
return;
}
// Transition to OPENING (or update stamp if already OPENING)
regionState.update(RegionState.State.OPENING,
data.getStamp(), data.getOrigin());
break;
case RS_ZK_REGION_OPENED:
// Should see OPENED after OPENING but possible after PENDING_OPEN
if (regionState == null ||
(!regionState.isPendingOpen() && !regionState.isOpening())) {
LOG.warn("Received OPENED for region " +
prettyPrintedRegionName +
" from server " + data.getOrigin() + " but region was in " +
" the state " + regionState + " and not " +
"in expected PENDING_OPEN or OPENING states");
return;
}
// Handle OPENED by removing from transition and deleted zk node
regionState.update(RegionState.State.OPEN,
data.getStamp(), data.getOrigin());
this.executorService.submit(
new OpenedRegionHandler(master, this, regionState.getRegion(),
data.getOrigin(), expectedVersion));
break;
}
}
}
/**
* @return Returns true if this RegionState is splittable; i.e. the
* RegionState is currently in splitting state or pending_close or
* null (Anything else will return false). (Anything else will return false).
*/
private boolean isInStateForSplitting(final RegionState rs) {
if (rs == null) return true;
if (rs.isSplitting()) return true;
if (convertPendingCloseToSplitting(rs)) return true;
LOG.warn("Dropped region split! Not in state good for SPLITTING; rs=" + rs);
return false;
}
/**
* If the passed regionState is in PENDING_CLOSE, clean up PENDING_CLOSE
* state and convert it to SPLITTING instead.
* This can happen in case where master wants to close a region at same time
* a regionserver starts a split. The split won. Clean out old PENDING_CLOSE
* state.
* @param rs
* @return True if we converted from PENDING_CLOSE to SPLITTING
*/
private boolean convertPendingCloseToSplitting(final RegionState rs) {
if (!rs.isPendingClose()) return false;
LOG.debug("Converting PENDING_CLOSE to SPLITING; rs=" + rs);
rs.update(RegionState.State.SPLITTING);
// Clean up existing state. Clear from region plans seems all we
// have to do here by way of clean up of PENDING_CLOSE.
clearRegionPlan(rs.getRegion());
return true;
}
/**
* @param serverName
* @param encodedName
* @return The SPLITTING RegionState we added to RIT for the passed region
* <code>encodedName</code>
*/
private RegionState addSplittingToRIT(final ServerName serverName,
final String encodedName) {
RegionState regionState = null;
synchronized (this.regions) {
regionState = findHRegionInfoThenAddToRIT(serverName, encodedName);
if (regionState != null) {
regionState.update(RegionState.State.SPLITTING,
System.currentTimeMillis(), serverName);
}
}
return regionState;
}
/**
* Caller must hold lock on <code>this.regions</code>.
* @param serverName
* @param encodedName
* @return The instance of RegionState that was added to RIT or null if error.
*/
private RegionState findHRegionInfoThenAddToRIT(final ServerName serverName,
final String encodedName) {
HRegionInfo hri = findHRegionInfo(serverName, encodedName);
if (hri == null) {
LOG.warn("Region " + encodedName + " not found on server " + serverName +
"; failed processing");
return null;
}
// Add to regions in transition, then update state to SPLITTING.
return addToRegionsInTransition(hri);
}
/**
* Caller must hold lock on <code>this.regions</code>.
* @param serverName
* @param encodedName
* @return Found HRegionInfo or null.
*/
private HRegionInfo findHRegionInfo(final ServerName sn,
final String encodedName) {
if (!this.serverManager.isServerOnline(sn)) return null;
Set<HRegionInfo> hris = this.servers.get(sn);
HRegionInfo foundHri = null;
for (HRegionInfo hri: hris) {
if (hri.getEncodedName().equals(encodedName)) {
foundHri = hri;
break;
}
}
return foundHri;
}
/**
* Handle a ZK unassigned node transition triggered by HBCK repair tool.
* <p>
* This is handled in a separate code path because it breaks the normal rules.
* @param data
*/
private void handleHBCK(RegionTransitionData data) {
String encodedName = HRegionInfo.encodeRegionName(data.getRegionName());
LOG.info("Handling HBCK triggered transition=" + data.getEventType() +
", server=" + data.getOrigin() + ", region=" +
HRegionInfo.prettyPrint(encodedName));
RegionState regionState = regionsInTransition.get(encodedName);
switch (data.getEventType()) {
case M_ZK_REGION_OFFLINE:
HRegionInfo regionInfo = null;
if (regionState != null) {
regionInfo = regionState.getRegion();
} else {
try {
regionInfo = MetaReader.getRegion(catalogTracker,
data.getRegionName()).getFirst();
} catch (IOException e) {
LOG.info("Exception reading META doing HBCK repair operation", e);
return;
}
}
LOG.info("HBCK repair is triggering assignment of region=" +
regionInfo.getRegionNameAsString());
// trigger assign, node is already in OFFLINE so don't need to update ZK
assign(regionInfo, false);
break;
default:
LOG.warn("Received unexpected region state from HBCK (" +
data.getEventType() + ")");
break;
}
}
// ZooKeeper events
/**
* New unassigned node has been created.
*
* <p>This happens when an RS begins the OPENING or CLOSING of a region by
* creating an unassigned node.
*
* <p>When this happens we must:
* <ol>
* <li>Watch the node for further events</li>
* <li>Read and handle the state in the node</li>
* </ol>
*/
@Override
public void nodeCreated(String path) {
if(path.startsWith(watcher.assignmentZNode)) {
try {
Stat stat = new Stat();
RegionTransitionData data = ZKAssign.getDataAndWatch(watcher, path, stat);
if (data == null) {
return;
}
handleRegion(data, stat.getVersion());
} catch (KeeperException e) {
master.abort("Unexpected ZK exception reading unassigned node data", e);
}
}
}
/**
* Existing unassigned node has had data changed.
*
* <p>This happens when an RS transitions from OFFLINE to OPENING, or between
* OPENING/OPENED and CLOSING/CLOSED.
*
* <p>When this happens we must:
* <ol>
* <li>Watch the node for further events</li>
* <li>Read and handle the state in the node</li>
* </ol>
*/
@Override
public void nodeDataChanged(String path) {
if(path.startsWith(watcher.assignmentZNode)) {
try {
Stat stat = new Stat();
RegionTransitionData data = ZKAssign.getDataAndWatch(watcher, path, stat);
if (data == null) {
return;
}
handleRegion(data, stat.getVersion());
} catch (KeeperException e) {
master.abort("Unexpected ZK exception reading unassigned node data", e);
}
}
}
@Override
public void nodeDeleted(final String path) {
if (path.startsWith(this.watcher.assignmentZNode)) {
String regionName = ZKAssign.getRegionName(this.master.getZooKeeper(), path);
RegionState rs = this.regionsInTransition.get(regionName);
if (rs != null) {
HRegionInfo regionInfo = rs.getRegion();
if (rs.isSplitting() || rs.isSplit()) {
LOG.debug("Ephemeral node deleted, regionserver crashed?, " +
"clearing from RIT; rs=" + rs);
clearRegionFromTransition(rs.getRegion());
} else {
LOG.debug("The znode of region " + regionInfo.getRegionNameAsString()
+ " has been deleted.");
if (rs.isOpened()) {
makeRegionOnline(rs, regionInfo);
}
}
}
}
}
private void makeRegionOnline(RegionState rs, HRegionInfo regionInfo) {
regionOnline(regionInfo, rs.serverName);
LOG.info("The master has opened the region "
+ regionInfo.getRegionNameAsString() + " that was online on "
+ rs.serverName);
if (this.getZKTable().isDisablingOrDisabledTable(
regionInfo.getTableNameAsString())) {
LOG.debug("Opened region "
+ regionInfo.getRegionNameAsString() + " but "
+ "this table is disabled, triggering close of region");
unassign(regionInfo);
}
}
/**
* New unassigned node has been created.
*
* <p>This happens when an RS begins the OPENING, SPLITTING or CLOSING of a
* region by creating a znode.
*
* <p>When this happens we must:
* <ol>
* <li>Watch the node for further children changed events</li>
* <li>Watch all new children for changed events</li>
* </ol>
*/
@Override
public void nodeChildrenChanged(String path) {
if(path.equals(watcher.assignmentZNode)) {
try {
// Just make sure we see the changes for the new znodes
ZKUtil.listChildrenAndWatchThem(watcher,
watcher.assignmentZNode);
} catch(KeeperException e) {
master.abort("Unexpected ZK exception reading unassigned children", e);
}
}
}
/**
* Marks the region as online. Removes it from regions in transition and
* updates the in-memory assignment information.
* <p>
* Used when a region has been successfully opened on a region server.
* @param regionInfo
* @param sn
*/
void regionOnline(HRegionInfo regionInfo, ServerName sn) {
synchronized (this.regionsInTransition) {
RegionState rs =
this.regionsInTransition.remove(regionInfo.getEncodedName());
if (rs != null) {
this.regionsInTransition.notifyAll();
}
}
synchronized (this.regions) {
// Add check
ServerName oldSn = this.regions.get(regionInfo);
if (oldSn != null) LOG.warn("Overwriting " + regionInfo.getEncodedName() +
" on " + oldSn + " with " + sn);
if (isServerOnline(sn)) {
this.regions.put(regionInfo, sn);
addToServers(sn, regionInfo);
this.regions.notifyAll();
} else {
LOG.info("The server is not in online servers, ServerName=" +
sn.getServerName() + ", region=" + regionInfo.getEncodedName());
}
}
// Remove plan if one.
clearRegionPlan(regionInfo);
// Update timers for all regions in transition going against this server.
updateTimers(sn);
}
/**
* Touch timers for all regions in transition that have the passed
* <code>sn</code> in common.
* Call this method whenever a server checks in. Doing so helps the case where
* a new regionserver has joined the cluster and its been given 1k regions to
* open. If this method is tickled every time the region reports in a
* successful open then the 1k-th region won't be timed out just because its
* sitting behind the open of 999 other regions. This method is NOT used
* as part of bulk assign -- there we have a different mechanism for extending
* the regions in transition timer (we turn it off temporarily -- because
* there is no regionplan involved when bulk assigning.
* @param sn
*/
private void updateTimers(final ServerName sn) {
// This loop could be expensive.
// First make a copy of current regionPlan rather than hold sync while
// looping because holding sync can cause deadlock. Its ok in this loop
// if the Map we're going against is a little stale
Map<String, RegionPlan> copy = new HashMap<String, RegionPlan>();
synchronized(this.regionPlans) {
copy.putAll(this.regionPlans);
}
for (Map.Entry<String, RegionPlan> e: copy.entrySet()) {
if (e.getValue() == null || e.getValue().getDestination() == null) continue;
if (!e.getValue().getDestination().equals(sn)) continue;
RegionState rs = null;
synchronized (this.regionsInTransition) {
rs = this.regionsInTransition.get(e.getKey());
}
if (rs == null) continue;
rs.updateTimestampToNow();
}
}
/**
* Marks the region as offline. Removes it from regions in transition and
* removes in-memory assignment information.
* <p>
* Used when a region has been closed and should remain closed.
* @param regionInfo
*/
public void regionOffline(final HRegionInfo regionInfo) {
synchronized(this.regionsInTransition) {
if (this.regionsInTransition.remove(regionInfo.getEncodedName()) != null) {
this.regionsInTransition.notifyAll();
}
}
// remove the region plan as well just in case.
clearRegionPlan(regionInfo);
setOffline(regionInfo);
}
/**
* Sets the region as offline by removing in-memory assignment information but
* retaining transition information.
* <p>
* Used when a region has been closed but should be reassigned.
* @param regionInfo
*/
public void setOffline(HRegionInfo regionInfo) {
synchronized (this.regions) {
ServerName sn = this.regions.remove(regionInfo);
if (sn == null) return;
Set<HRegionInfo> serverRegions = this.servers.get(sn);
if (!serverRegions.remove(regionInfo)) {
LOG.warn("No " + regionInfo + " on " + sn);
}
}
}
public void offlineDisabledRegion(HRegionInfo regionInfo) {
// Disabling so should not be reassigned, just delete the CLOSED node
LOG.debug("Table being disabled so deleting ZK node and removing from " +
"regions in transition, skipping assignment of region " +
regionInfo.getRegionNameAsString());
try {
if (!ZKAssign.deleteClosedNode(watcher, regionInfo.getEncodedName())) {
// Could also be in OFFLINE mode
ZKAssign.deleteOfflineNode(watcher, regionInfo.getEncodedName());
}
} catch (KeeperException.NoNodeException nne) {
LOG.debug("Tried to delete closed node for " + regionInfo + " but it " +
"does not exist so just offlining");
} catch (KeeperException e) {
this.master.abort("Error deleting CLOSED node in ZK", e);
}
regionOffline(regionInfo);
}
// Assignment methods
/**
* Assigns the specified region.
* <p>
* If a RegionPlan is available with a valid destination then it will be used
* to determine what server region is assigned to. If no RegionPlan is
* available, region will be assigned to a random available server.
* <p>
* Updates the RegionState and sends the OPEN RPC.
* <p>
* This will only succeed if the region is in transition and in a CLOSED or
* OFFLINE state or not in transition (in-memory not zk), and of course, the
* chosen server is up and running (It may have just crashed!). If the
* in-memory checks pass, the zk node is forced to OFFLINE before assigning.
*
* @param region server to be assigned
* @param setOfflineInZK whether ZK node should be created/transitioned to an
* OFFLINE state before assigning the region
*/
public void assign(HRegionInfo region, boolean setOfflineInZK) {
assign(region, setOfflineInZK, false);
}
public void assign(HRegionInfo region, boolean setOfflineInZK,
boolean forceNewPlan) {
assign(region, setOfflineInZK, forceNewPlan, false);
}
/**
* @param region
* @param setOfflineInZK
* @param forceNewPlan
* @param hijack
* - true new assignment is needed, false otherwise
*/
public void assign(HRegionInfo region, boolean setOfflineInZK,
boolean forceNewPlan, boolean hijack) {
// If hijack is true do not call disableRegionIfInRIT as
// we have not yet moved the znode to OFFLINE state.
if (!hijack && isDisabledorDisablingRegionInRIT(region)) {
return;
}
if (this.serverManager.isClusterShutdown()) {
LOG.info("Cluster shutdown is set; skipping assign of " +
region.getRegionNameAsString());
return;
}
RegionState state = addToRegionsInTransition(region,
hijack);
synchronized (state) {
assign(region, state, setOfflineInZK, forceNewPlan, hijack);
}
}
/**
* Bulk assign regions to <code>destination</code>.
* @param destination
* @param regions Regions to assign.
*/
void assign(final ServerName destination,
final List<HRegionInfo> regions) {
if (regions.size() == 0) {
return;
}
LOG.debug("Bulk assigning " + regions.size() + " region(s) to " +
destination.toString());
List<RegionState> states = new ArrayList<RegionState>(regions.size());
synchronized (this.regionsInTransition) {
for (HRegionInfo region: regions) {
states.add(forceRegionStateToOffline(region));
}
}
// Presumption is that only this thread will be updating the state at this
// time; i.e. handlers on backend won't be trying to set it to OPEN, etc.
AtomicInteger counter = new AtomicInteger(0);
CreateUnassignedAsyncCallback cb =
new CreateUnassignedAsyncCallback(this.watcher, destination, counter);
for (RegionState state: states) {
if (!asyncSetOfflineInZooKeeper(state, cb, state)) {
return;
}
}
// Wait until all unassigned nodes have been put up and watchers set.
int total = regions.size();
for (int oldCounter = 0; true;) {
int count = counter.get();
if (oldCounter != count) {
LOG.info(destination.toString() + " unassigned znodes=" + count +
" of total=" + total);
oldCounter = count;
}
if (count == total) break;
Threads.sleep(1);
}
// Move on to open regions.
try {
// Send OPEN RPC. If it fails on a IOE or RemoteException, the
// TimeoutMonitor will pick up the pieces.
long maxWaitTime = System.currentTimeMillis() +
this.master.getConfiguration().
getLong("hbase.regionserver.rpc.startup.waittime", 60000);
while (!this.master.isStopped()) {
try {
this.serverManager.sendRegionOpen(destination, regions);
break;
} catch (RemoteException e) {
IOException decodedException = e.unwrapRemoteException();
if (decodedException instanceof RegionServerStoppedException) {
LOG.warn("The region server was shut down, ", decodedException);
// No need to retry, the region server is a goner.
return;
} else if (decodedException instanceof ServerNotRunningYetException) {
// This is the one exception to retry. For all else we should just fail
// the startup.
long now = System.currentTimeMillis();
if (now > maxWaitTime) throw e;
LOG.debug("Server is not yet up; waiting up to " +
(maxWaitTime - now) + "ms", e);
Thread.sleep(1000);
}
throw decodedException;
}
}
} catch (IOException e) {
// Can be a socket timeout, EOF, NoRouteToHost, etc
LOG.info("Unable to communicate with the region server in order" +
" to assign regions", e);
} catch (InterruptedException e) {
throw new RuntimeException(e);
}
LOG.debug("Bulk assigning done for " + destination.toString());
}
/**
* Callback handler for create unassigned znodes used during bulk assign.
*/
static class CreateUnassignedAsyncCallback implements AsyncCallback.StringCallback {
private final Log LOG = LogFactory.getLog(CreateUnassignedAsyncCallback.class);
private final ZooKeeperWatcher zkw;
private final ServerName destination;
private final AtomicInteger counter;
CreateUnassignedAsyncCallback(final ZooKeeperWatcher zkw,
final ServerName destination, final AtomicInteger counter) {
this.zkw = zkw;
this.destination = destination;
this.counter = counter;
}
@Override
public void processResult(int rc, String path, Object ctx, String name) {
if (rc != 0) {
// Thisis resultcode. If non-zero, need to resubmit.
LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
"FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
this.zkw.abort("Connectionloss writing unassigned at " + path +
", rc=" + rc, null);
return;
}
LOG.debug("rs=" + (RegionState)ctx + ", server=" + this.destination.toString());
// Async exists to set a watcher so we'll get triggered when
// unassigned node changes.
this.zkw.getRecoverableZooKeeper().getZooKeeper().exists(path, this.zkw,
new ExistsUnassignedAsyncCallback(this.counter, destination), ctx);
}
}
/**
* Callback handler for the exists call that sets watcher on unassigned znodes.
* Used during bulk assign on startup.
*/
static class ExistsUnassignedAsyncCallback implements AsyncCallback.StatCallback {
private final Log LOG = LogFactory.getLog(ExistsUnassignedAsyncCallback.class);
private final AtomicInteger counter;
private ServerName destination;
ExistsUnassignedAsyncCallback(final AtomicInteger counter, ServerName destination) {
this.counter = counter;
this.destination = destination;
}
@Override
public void processResult(int rc, String path, Object ctx, Stat stat) {
if (rc != 0) {
// Thisis resultcode. If non-zero, need to resubmit.
LOG.warn("rc != 0 for " + path + " -- retryable connectionloss -- " +
"FIX see http://wiki.apache.org/hadoop/ZooKeeper/FAQ#A2");
return;
}
RegionState state = (RegionState)ctx;
LOG.debug("rs=" + state);
// Transition RegionState to PENDING_OPEN here in master; means we've
// sent the open. We're a little ahead of ourselves here since we've not
// yet sent out the actual open but putting this state change after the
// call to open risks our writing PENDING_OPEN after state has been moved
// to OPENING by the regionserver.
state.update(RegionState.State.PENDING_OPEN, System.currentTimeMillis(), destination);
this.counter.addAndGet(1);
}
}
/**
* @param region
* @return The current RegionState
*/
private RegionState addToRegionsInTransition(final HRegionInfo region) {
return addToRegionsInTransition(region, false);
}
/**
* @param region
* @param hijack
* @return The current RegionState
*/
private RegionState addToRegionsInTransition(final HRegionInfo region,
boolean hijack) {
synchronized (regionsInTransition) {
return forceRegionStateToOffline(region, hijack);
}
}
/**
* Sets regions {@link RegionState} to {@link RegionState.State#OFFLINE}.
* Caller must hold lock on this.regionsInTransition.
* @param region
* @return Amended RegionState.
*/
private RegionState forceRegionStateToOffline(final HRegionInfo region) {
return forceRegionStateToOffline(region, false);
}
/**
* Sets regions {@link RegionState} to {@link RegionState.State#OFFLINE}.
* Caller must hold lock on this.regionsInTransition.
* @param region
* @param hijack
* @return Amended RegionState.
*/
private RegionState forceRegionStateToOffline(final HRegionInfo region,
boolean hijack) {
String encodedName = region.getEncodedName();
RegionState state = this.regionsInTransition.get(encodedName);
if (state == null) {
state = new RegionState(region, RegionState.State.OFFLINE);
this.regionsInTransition.put(encodedName, state);
} else {
// If we are reassigning the node do not force in-memory state to OFFLINE.
// Based on the znode state we will decide if to change
// in-memory state to OFFLINE or not. It will
// be done before setting the znode to OFFLINE state.
if (!hijack) {
LOG.debug("Forcing OFFLINE; was=" + state);
state.update(RegionState.State.OFFLINE);
}
}
return state;
}
/**
* Caller must hold lock on the passed <code>state</code> object.
* @param state
* @param setOfflineInZK
* @param forceNewPlan
* @param hijack
*/
private void assign(final HRegionInfo region, final RegionState state,
final boolean setOfflineInZK, final boolean forceNewPlan,
boolean hijack) {
for (int i = 0; i < this.maximumAssignmentAttempts; i++) {
int versionOfOfflineNode = -1;
if (setOfflineInZK) {
// get the version of the znode after setting it to OFFLINE.
// versionOfOfflineNode will be -1 if the znode was not set to OFFLINE
versionOfOfflineNode = setOfflineInZooKeeper(state,
hijack);
if(versionOfOfflineNode != -1){
if (isDisabledorDisablingRegionInRIT(region)) {
return;
}
}
}
if (setOfflineInZK && versionOfOfflineNode == -1) {
return;
}
if (this.master.isStopped()) {
LOG.debug("Server stopped; skipping assign of " + state);
return;
}
RegionPlan plan = getRegionPlan(state, forceNewPlan);
if (plan == null) {
LOG.debug("Unable to determine a plan to assign " + state);
return; // Should get reassigned later when RIT times out.
}
try {
LOG.debug("Assigning region " + state.getRegion().getRegionNameAsString() +
" to " + plan.getDestination().toString());
// Transition RegionState to PENDING_OPEN
state.update(RegionState.State.PENDING_OPEN, System.currentTimeMillis(),
plan.getDestination());
// Send OPEN RPC. This can fail if the server on other end is is not up.
// Pass the version that was obtained while setting the node to OFFLINE.
RegionOpeningState regionOpenState = serverManager.sendRegionOpen(plan
.getDestination(), state.getRegion(), versionOfOfflineNode);
if (regionOpenState == RegionOpeningState.ALREADY_OPENED) {
// Remove region from in-memory transition and unassigned node from ZK
// While trying to enable the table the regions of the table were
// already enabled.
LOG.debug("ALREADY_OPENED region " + state.getRegion().getRegionNameAsString() +
" to " + plan.getDestination().toString());
String encodedRegionName = state.getRegion()
.getEncodedName();
try {
ZKAssign.deleteOfflineNode(master.getZooKeeper(), encodedRegionName);
} catch (KeeperException.NoNodeException e) {
if(LOG.isDebugEnabled()){
LOG.debug("The unassigned node "+encodedRegionName+" doesnot exist.");
}
} catch (KeeperException e) {
master.abort(
"Error deleting OFFLINED node in ZK for transition ZK node ("
+ encodedRegionName + ")", e);
}
synchronized (this.regionsInTransition) {
this.regionsInTransition.remove(plan.getRegionInfo()
.getEncodedName());
}
synchronized (this.regions) {
this.regions.put(plan.getRegionInfo(), plan.getDestination());
}
}
break;
} catch (Throwable t) {
if (t instanceof RemoteException) {
t = ((RemoteException) t).unwrapRemoteException();
if (t instanceof RegionAlreadyInTransitionException) {
String errorMsg = "Failed assignment in: " + plan.getDestination()
+ " due to " + t.getMessage();
LOG.error(errorMsg, t);
return;
}
}
LOG.warn("Failed assignment of " +
state.getRegion().getRegionNameAsString() + " to " +
plan.getDestination() + ", trying to assign elsewhere instead; " +
"retry=" + i, t);
// Clean out plan we failed execute and one that doesn't look like it'll
// succeed anyways; we need a new plan!
// Transition back to OFFLINE
state.update(RegionState.State.OFFLINE);
// Force a new plan and reassign. Will return null if no servers.
if (getRegionPlan(state, plan.getDestination(), true) == null) {
this.timeoutMonitor.setAllRegionServersOffline(true);
LOG.warn("Unable to find a viable location to assign region " +
state.getRegion().getRegionNameAsString());
return;
}
}
}
}
private boolean isDisabledorDisablingRegionInRIT(final HRegionInfo region) {
String tableName = region.getTableNameAsString();
boolean disabled = this.zkTable.isDisabledTable(tableName);
if (disabled || this.zkTable.isDisablingTable(tableName)) {
LOG.info("Table " + tableName + (disabled ? " disabled;" : " disabling;") +
" skipping assign of " + region.getRegionNameAsString());
offlineDisabledRegion(region);
return true;
}
return false;
}
/**
* Set region as OFFLINED up in zookeeper
*
* @param state
* @param hijack
* - true if needs to be hijacked and reassigned, false otherwise.
* @return the version of the offline node if setting of the OFFLINE node was
* successful, -1 otherwise.
*/
int setOfflineInZooKeeper(final RegionState state,
boolean hijack) {
// In case of reassignment the current state in memory need not be
// OFFLINE.
if (!hijack && !state.isClosed() && !state.isOffline()) {
this.master.abort("Unexpected state trying to OFFLINE; " + state,
new IllegalStateException());
return -1;
}
boolean allowZNodeCreation = false;
// Under reassignment if the current state is PENDING_OPEN
// or OPENING then refresh the in-memory state to PENDING_OPEN. This is
// important because if the region was in
// RS_OPENING state for a long time the master will try to force the znode
// to OFFLINE state meanwhile the RS could have opened the corresponding
// region and the state in znode will be RS_ZK_REGION_OPENED.
// For all other cases we can change the in-memory state to OFFLINE.
if (hijack &&
(state.getState().equals(RegionState.State.PENDING_OPEN) ||
state.getState().equals(RegionState.State.OPENING))) {
state.update(RegionState.State.PENDING_OPEN);
allowZNodeCreation = false;
} else {
state.update(RegionState.State.OFFLINE);
allowZNodeCreation = true;
}
int versionOfOfflineNode = -1;
try {
// get the version after setting the znode to OFFLINE
versionOfOfflineNode = ZKAssign.createOrForceNodeOffline(master.getZooKeeper(),
state.getRegion(), this.master.getServerName(),
hijack, allowZNodeCreation);
if (versionOfOfflineNode == -1) {
LOG.warn("Attempted to create/force node into OFFLINE state before "
+ "completing assignment but failed to do so for " + state);
return -1;
}
} catch (KeeperException e) {
master.abort("Unexpected ZK exception creating/setting node OFFLINE", e);
return -1;
}
return versionOfOfflineNode;
}
/**
* Set region as OFFLINED up in zookeeper asynchronously.
* @param state
* @return True if we succeeded, false otherwise (State was incorrect or failed
* updating zk).
*/
boolean asyncSetOfflineInZooKeeper(final RegionState state,
final AsyncCallback.StringCallback cb, final Object ctx) {
if (!state.isClosed() && !state.isOffline()) {
new RuntimeException("Unexpected state trying to OFFLINE; " + state);
this.master.abort("Unexpected state trying to OFFLINE; " + state,
new IllegalStateException());
return false;
}
state.update(RegionState.State.OFFLINE);
try {
ZKAssign.asyncCreateNodeOffline(master.getZooKeeper(), state.getRegion(),
this.master.getServerName(), cb, ctx);
} catch (KeeperException e) {
master.abort("Unexpected ZK exception creating/setting node OFFLINE", e);
return false;
}
return true;
}
/**
* @param state
* @return Plan for passed <code>state</code> (If none currently, it creates one or
* if no servers to assign, it returns null).
*/
RegionPlan getRegionPlan(final RegionState state,
final boolean forceNewPlan) {
return getRegionPlan(state, null, forceNewPlan);
}
/**
* @param state
* @param serverToExclude Server to exclude (we know its bad). Pass null if
* all servers are thought to be assignable.
* @param forceNewPlan If true, then if an existing plan exists, a new plan
* will be generated.
* @return Plan for passed <code>state</code> (If none currently, it creates one or
* if no servers to assign, it returns null).
*/
RegionPlan getRegionPlan(final RegionState state,
final ServerName serverToExclude, final boolean forceNewPlan) {
// Pickup existing plan or make a new one
final String encodedName = state.getRegion().getEncodedName();
final List<ServerName> servers = this.serverManager.getOnlineServersList();
final List<ServerName> drainingServers = this.serverManager.getDrainingServersList();
if (serverToExclude != null) servers.remove(serverToExclude);
// Loop through the draining server list and remove them from the server
// list.
if (!drainingServers.isEmpty()) {
for (final ServerName server: drainingServers) {
LOG.debug("Removing draining server: " + server +
" from eligible server pool.");
servers.remove(server);
}
}
if (servers.isEmpty()) return null;
RegionPlan randomPlan = new RegionPlan(state.getRegion(), null,
balancer.randomAssignment(servers));
boolean newPlan = false;
RegionPlan existingPlan = null;
synchronized (this.regionPlans) {
existingPlan = this.regionPlans.get(encodedName);
if (existingPlan != null && existingPlan.getDestination() != null) {
LOG.debug("Found an existing plan for " +
state.getRegion().getRegionNameAsString() +
" destination server is + " + existingPlan.getDestination().toString());
}
if (forceNewPlan
|| existingPlan == null
|| existingPlan.getDestination() == null
|| drainingServers.contains(existingPlan.getDestination())) {
newPlan = true;
this.regionPlans.put(encodedName, randomPlan);
}
}
if (newPlan) {
LOG.debug("No previous transition plan was found (or we are ignoring " +
"an existing plan) for " + state.getRegion().getRegionNameAsString() +
" so generated a random one; " + randomPlan + "; " +
serverManager.countOfRegionServers() +
" (online=" + serverManager.getOnlineServers().size() +
", exclude=" + drainingServers.size() + ") available servers");
return randomPlan;
}
LOG.debug("Using pre-existing plan for region " +
state.getRegion().getRegionNameAsString() + "; plan=" + existingPlan);
return existingPlan;
}
/**
* Unassign the list of regions. Configuration knobs:
* hbase.bulk.waitbetween.reopen indicates the number of milliseconds to
* wait before unassigning another region from this region server
*
* @param regions
* @throws InterruptedException
*/
public void unassign(List<HRegionInfo> regions) {
int waitTime = this.master.getConfiguration().getInt(
"hbase.bulk.waitbetween.reopen", 0);
for (HRegionInfo region : regions) {
if (isRegionInTransition(region) != null)
continue;
unassign(region, false);
while (isRegionInTransition(region) != null) {
try {
Thread.sleep(10);
} catch (InterruptedException e) {
// Do nothing, continue
}
}
if (waitTime > 0)
try {
Thread.sleep(waitTime);
} catch (InterruptedException e) {
// Do nothing, continue
}
}
}
/**
* Unassigns the specified region.
* <p>
* Updates the RegionState and sends the CLOSE RPC unless region is being
* split by regionserver; then the unassign fails (silently) because we
* presume the region being unassigned no longer exists (its been split out
* of existence). TODO: What to do if split fails and is rolled back and
* parent is revivified?
* <p>
* If a RegionPlan is already set, it will remain.
*
* @param region server to be unassigned
*/
public void unassign(HRegionInfo region) {
unassign(region, false);
}
/**
* Unassigns the specified region.
* <p>
* Updates the RegionState and sends the CLOSE RPC unless region is being
* split by regionserver; then the unassign fails (silently) because we
* presume the region being unassigned no longer exists (its been split out
* of existence). TODO: What to do if split fails and is rolled back and
* parent is revivified?
* <p>
* If a RegionPlan is already set, it will remain.
*
* @param region server to be unassigned
* @param force if region should be closed even if already closing
*/
public void unassign(HRegionInfo region, boolean force) {
// TODO: Method needs refactoring. Ugly buried returns throughout. Beware!
LOG.debug("Starting unassignment of region " +
region.getRegionNameAsString() + " (offlining)");
synchronized (this.regions) {
// Check if this region is currently assigned
if (!regions.containsKey(region)) {
LOG.debug("Attempted to unassign region " +
region.getRegionNameAsString() + " but it is not " +
"currently assigned anywhere");
return;
}
}
String encodedName = region.getEncodedName();
// Grab the state of this region and synchronize on it
RegionState state;
int versionOfClosingNode = -1;
synchronized (regionsInTransition) {
state = regionsInTransition.get(encodedName);
if (state == null) {
// Create the znode in CLOSING state
try {
versionOfClosingNode = ZKAssign.createNodeClosing(
master.getZooKeeper(), region, master.getServerName());
if (versionOfClosingNode == -1) {
LOG.debug("Attempting to unassign region " +
region.getRegionNameAsString() + " but ZK closing node "
+ "can't be created.");
return;
}
} catch (KeeperException e) {
if (e instanceof NodeExistsException) {
// Handle race between master initiated close and regionserver
// orchestrated splitting. See if existing node is in a
// SPLITTING or SPLIT state. If so, the regionserver started
// an op on node before we could get our CLOSING in. Deal.
NodeExistsException nee = (NodeExistsException)e;
String path = nee.getPath();
try {
if (isSplitOrSplitting(path)) {
LOG.debug(path + " is SPLIT or SPLITTING; " +
"skipping unassign because region no longer exists -- its split");
return;
}
} catch (KeeperException.NoNodeException ke) {
LOG.warn("Failed getData on SPLITTING/SPLIT at " + path +
"; presuming split and that the region to unassign, " +
encodedName + ", no longer exists -- confirm", ke);
return;
} catch (KeeperException ke) {
LOG.error("Unexpected zk state", ke);
ke = e;
}
}
// If we get here, don't understand whats going on -- abort.
master.abort("Unexpected ZK exception creating node CLOSING", e);
return;
}
state = new RegionState(region, RegionState.State.PENDING_CLOSE);
regionsInTransition.put(encodedName, state);
} else if (force && (state.isPendingClose() || state.isClosing())) {
LOG.debug("Attempting to unassign region " + region.getRegionNameAsString() +
" which is already " + state.getState() +
" but forcing to send a CLOSE RPC again ");
state.update(state.getState());
} else {
LOG.debug("Attempting to unassign region " +
region.getRegionNameAsString() + " but it is " +
"already in transition (" + state.getState() + ", force=" + force + ")");
return;
}
}
// Send CLOSE RPC
ServerName server = null;
synchronized (this.regions) {
server = regions.get(region);
}
try {
// TODO: We should consider making this look more like it does for the
// region open where we catch all throwables and never abort
if (serverManager.sendRegionClose(server, state.getRegion(),
versionOfClosingNode)) {
LOG.debug("Sent CLOSE to " + server + " for region " +
region.getRegionNameAsString());
return;
}
// This never happens. Currently regionserver close always return true.
LOG.warn("Server " + server + " region CLOSE RPC returned false for " +
region.getRegionNameAsString());
} catch (NotServingRegionException nsre) {
LOG.info("Server " + server + " returned " + nsre + " for " +
region.getRegionNameAsString());
// Presume that master has stale data. Presume remote side just split.
// Presume that the split message when it comes in will fix up the master's
// in memory cluster state.
} catch (Throwable t) {
if (t instanceof RemoteException) {
t = ((RemoteException)t).unwrapRemoteException();
if (t instanceof NotServingRegionException) {
if (checkIfRegionBelongsToDisabling(region)) {
// Remove from the regionsinTransition map
LOG.info("While trying to recover the table "
+ region.getTableNameAsString()
+ " to DISABLED state the region " + region
+ " was offlined but the table was in DISABLING state");
synchronized (this.regionsInTransition) {
this.regionsInTransition.remove(region.getEncodedName());
}
// Remove from the regionsMap
synchronized (this.regions) {
this.regions.remove(region);
}
}
}
// RS is already processing this region, only need to update the timestamp
if (t instanceof RegionAlreadyInTransitionException) {
LOG.debug("update " + state + " the timestamp.");
state.update(state.getState());
}
}
LOG.info("Server " + server + " returned " + t + " for " +
region.getEncodedName());
// Presume retry or server will expire.
}
}
/**
* @param path
* @return True if znode is in SPLIT or SPLITTING state.
* @throws KeeperException Can happen if the znode went away in meantime.
*/
private boolean isSplitOrSplitting(final String path) throws KeeperException {
boolean result = false;
// This may fail if the SPLIT or SPLITTING znode gets cleaned up before we
// can get data from it.
RegionTransitionData data = ZKAssign.getData(master.getZooKeeper(), path);
EventType evt = data.getEventType();
switch (evt) {
case RS_ZK_REGION_SPLIT:
case RS_ZK_REGION_SPLITTING:
result = true;
break;
default:
break;
}
return result;
}
/**
* Waits until the specified region has completed assignment.
* <p>
* If the region is already assigned, returns immediately. Otherwise, method
* blocks until the region is assigned.
* @param regionInfo region to wait on assignment for
* @throws InterruptedException
*/
public void waitForAssignment(HRegionInfo regionInfo)
throws InterruptedException {
synchronized(regions) {
while(!regions.containsKey(regionInfo)) {
regions.wait();
}
}
}
/**
* Assigns the ROOT region.
* <p>
* Assumes that ROOT is currently closed and is not being actively served by
* any RegionServer.
* <p>
* Forcibly unsets the current root region location in ZooKeeper and assigns
* ROOT to a random RegionServer.
* @throws KeeperException
*/
public void assignRoot() throws KeeperException {
RootLocationEditor.deleteRootLocation(this.master.getZooKeeper());
assign(HRegionInfo.ROOT_REGIONINFO, true);
}
/**
* Assigns the META region.
* <p>
* Assumes that META is currently closed and is not being actively served by
* any RegionServer.
* <p>
* Forcibly assigns META to a random RegionServer.
*/
public void assignMeta() {
// Force assignment to a random server
assign(HRegionInfo.FIRST_META_REGIONINFO, true);
}
/**
* Assigns all user regions, if any. Used during cluster startup.
* <p>
* This is a synchronous call and will return once every region has been
* assigned. If anything fails, an exception is thrown
* @throws InterruptedException
* @throws IOException
*/
public void assignUserRegions(List<HRegionInfo> regions, List<ServerName> servers)
throws IOException, InterruptedException {
if (regions == null)
return;
Map<ServerName, List<HRegionInfo>> bulkPlan = null;
// Generate a round-robin bulk assignment plan
bulkPlan = balancer.roundRobinAssignment(regions, servers);
LOG.info("Bulk assigning " + regions.size() + " region(s) round-robin across " +
servers.size() + " server(s)");
// Use fixed count thread pool assigning.
BulkAssigner ba = new StartupBulkAssigner(this.master, bulkPlan, this);
ba.bulkAssign();
LOG.info("Bulk assigning done");
}
/**
* Assigns all user regions, if any exist. Used during cluster startup.
* <p>
* This is a synchronous call and will return once every region has been
* assigned. If anything fails, an exception is thrown and the cluster
* should be shutdown.
* @throws InterruptedException
* @throws IOException
*/
public void assignAllUserRegions() throws IOException, InterruptedException {
// Get all available servers
List<ServerName> servers = serverManager.getOnlineServersList();
// If there are no servers we need not proceed with region assignment.
if(servers.isEmpty()) return;
// Scan META for all user regions, skipping any disabled tables
Map<HRegionInfo, ServerName> allRegions =
MetaReader.fullScan(catalogTracker, this.zkTable.getDisabledTables(), true);
if (allRegions == null || allRegions.isEmpty()) return;
// Determine what type of assignment to do on startup
boolean retainAssignment = master.getConfiguration().
getBoolean("hbase.master.startup.retainassign", true);
Map<ServerName, List<HRegionInfo>> bulkPlan = null;
if (retainAssignment) {
// Reuse existing assignment info
bulkPlan = balancer.retainAssignment(allRegions, servers);
} else {
// assign regions in round-robin fashion
assignUserRegions(new ArrayList<HRegionInfo>(allRegions.keySet()), servers);
return;
}
LOG.info("Bulk assigning " + allRegions.size() + " region(s) across " +
servers.size() + " server(s), retainAssignment=" + retainAssignment);
// Use fixed count thread pool assigning.
BulkAssigner ba = new StartupBulkAssigner(this.master, bulkPlan, this);
ba.bulkAssign();
LOG.info("Bulk assigning done");
}
/**
* Run bulk assign on startup. Does one RCP per regionserver passing a
* batch of reginons using {@link SingleServerBulkAssigner}.
* Uses default {@link #getUncaughtExceptionHandler()}
* which will abort the Server if exception.
*/
static class StartupBulkAssigner extends BulkAssigner {
final Map<ServerName, List<HRegionInfo>> bulkPlan;
final AssignmentManager assignmentManager;
StartupBulkAssigner(final Server server,
final Map<ServerName, List<HRegionInfo>> bulkPlan,
final AssignmentManager am) {
super(server);
this.bulkPlan = bulkPlan;
this.assignmentManager = am;
}
@Override
public boolean bulkAssign(boolean sync) throws InterruptedException {
// Disable timing out regions in transition up in zk while bulk assigning.
this.assignmentManager.timeoutMonitor.bulkAssign(true);
try {
return super.bulkAssign(sync);
} finally {
// Reenable timing out regions in transition up in zi.
this.assignmentManager.timeoutMonitor.bulkAssign(false);
}
}
@Override
protected String getThreadNamePrefix() {
return this.server.getServerName() + "-StartupBulkAssigner";
}
@Override
protected void populatePool(java.util.concurrent.ExecutorService pool) {
for (Map.Entry<ServerName, List<HRegionInfo>> e: this.bulkPlan.entrySet()) {
pool.execute(new SingleServerBulkAssigner(e.getKey(), e.getValue(),
this.assignmentManager));
}
}
protected boolean waitUntilDone(final long timeout)
throws InterruptedException {
Set<HRegionInfo> regionSet = new HashSet<HRegionInfo>();
for (List<HRegionInfo> regionList : bulkPlan.values()) {
regionSet.addAll(regionList);
}
return this.assignmentManager.waitUntilNoRegionsInTransition(timeout, regionSet);
}
@Override
protected long getTimeoutOnRIT() {
// Guess timeout. Multiply the number of regions on a random server
// by how long we thing one region takes opening.
long perRegionOpenTimeGuesstimate =
this.server.getConfiguration().getLong("hbase.bulk.assignment.perregion.open.time", 1000);
int regionsPerServer =
this.bulkPlan.entrySet().iterator().next().getValue().size();
long timeout = perRegionOpenTimeGuesstimate * regionsPerServer;
LOG.debug("Timeout-on-RIT=" + timeout);
return timeout;
}
}
/**
* Bulk user region assigner.
* If failed assign, lets timeout in RIT do cleanup.
*/
static class GeneralBulkAssigner extends StartupBulkAssigner {
GeneralBulkAssigner(final Server server,
final Map<ServerName, List<HRegionInfo>> bulkPlan,
final AssignmentManager am) {
super(server, bulkPlan, am);
}
@Override
protected UncaughtExceptionHandler getUncaughtExceptionHandler() {
return new UncaughtExceptionHandler() {
@Override
public void uncaughtException(Thread t, Throwable e) {
LOG.warn("Assigning regions in " + t.getName(), e);
}
};
}
}
/**
* Manage bulk assigning to a server.
*/
static class SingleServerBulkAssigner implements Runnable {
private final ServerName regionserver;
private final List<HRegionInfo> regions;
private final AssignmentManager assignmentManager;
SingleServerBulkAssigner(final ServerName regionserver,
final List<HRegionInfo> regions, final AssignmentManager am) {
this.regionserver = regionserver;
this.regions = regions;
this.assignmentManager = am;
}
@Override
public void run() {
this.assignmentManager.assign(this.regionserver, this.regions);
}
}
/**
* Wait until no regions in transition.
* @param timeout How long to wait.
* @return True if nothing in regions in transition.
* @throws InterruptedException
*/
boolean waitUntilNoRegionsInTransition(final long timeout)
throws InterruptedException {
// Blocks until there are no regions in transition. It is possible that
// there
// are regions in transition immediately after this returns but guarantees
// that if it returns without an exception that there was a period of time
// with no regions in transition from the point-of-view of the in-memory
// state of the Master.
long startTime = System.currentTimeMillis();
long remaining = timeout;
synchronized (regionsInTransition) {
while (regionsInTransition.size() > 0 && !this.master.isStopped()
&& remaining > 0) {
regionsInTransition.wait(remaining);
remaining = timeout - (System.currentTimeMillis() - startTime);
}
}
return regionsInTransition.isEmpty();
}
/**
* Wait until no regions from set regions are in transition.
* @param timeout How long to wait.
* @param regions set of regions to wait for
* @return True if nothing in regions in transition.
* @throws InterruptedException
*/
boolean waitUntilNoRegionsInTransition(final long timeout, Set<HRegionInfo> regions)
throws InterruptedException {
// Blocks until there are no regions in transition.
long startTime = System.currentTimeMillis();
long remaining = timeout;
boolean stillInTransition = true;
synchronized (regionsInTransition) {
while (regionsInTransition.size() > 0 && !this.master.isStopped() &&
remaining > 0 && stillInTransition) {
int count = 0;
for (RegionState rs : regionsInTransition.values()) {
if (regions.contains(rs.getRegion())) {
count++;
break;
}
}
if (count == 0) {
stillInTransition = false;
break;
}
regionsInTransition.wait(remaining);
remaining = timeout - (System.currentTimeMillis() - startTime);
}
}
return stillInTransition;
}
/**
* Rebuild the list of user regions and assignment information.
* <p>
* Returns a map of servers that are not found to be online and the regions
* they were hosting.
* @return map of servers not online to their assigned regions, as stored
* in META
* @throws IOException
*/
Map<ServerName, List<Pair<HRegionInfo, Result>>> rebuildUserRegions()
throws IOException, KeeperException {
// Region assignment from META
List<Result> results = MetaReader.fullScan(this.catalogTracker);
// Map of offline servers and their regions to be returned
Map<ServerName, List<Pair<HRegionInfo,Result>>> offlineServers =
new TreeMap<ServerName, List<Pair<HRegionInfo, Result>>>();
// Iterate regions in META
for (Result result : results) {
Pair<HRegionInfo, ServerName> region = MetaReader.parseCatalogResult(result);
if (region == null) continue;
HRegionInfo regionInfo = region.getFirst();
ServerName regionLocation = region.getSecond();
String tableName = regionInfo.getTableNameAsString();
if (regionLocation == null) {
// regionLocation could be null if createTable didn't finish properly.
// When createTable is in progress, HMaster restarts.
// Some regions have been added to .META., but have not been assigned.
// When this happens, the region's table must be in ENABLING state.
// It can't be in ENABLED state as that is set when all regions are
// assigned.
// It can't be in DISABLING state, because DISABLING state transitions
// from ENABLED state when application calls disableTable.
// It can't be in DISABLED state, because DISABLED states transitions
// from DISABLING state.
if (false == checkIfRegionsBelongsToEnabling(regionInfo)) {
LOG.warn("Region " + regionInfo.getEncodedName() +
" has null regionLocation." + " But its table " + tableName +
" isn't in ENABLING state.");
}
addTheTablesInPartialState(this.disablingTables, this.enablingTables, regionInfo,
tableName);
} else if (!this.serverManager.isServerOnline(regionLocation)) {
// Region is located on a server that isn't online
List<Pair<HRegionInfo, Result>> offlineRegions =
offlineServers.get(regionLocation);
if (offlineRegions == null) {
offlineRegions = new ArrayList<Pair<HRegionInfo,Result>>(1);
offlineServers.put(regionLocation, offlineRegions);
}
offlineRegions.add(new Pair<HRegionInfo,Result>(regionInfo, result));
} else {
// Region is being served and on an active server
// add only if region not in disabled and enabling table
if (false == checkIfRegionBelongsToDisabled(regionInfo)
&& false == checkIfRegionsBelongsToEnabling(regionInfo)) {
regions.put(regionInfo, regionLocation);
addToServers(regionLocation, regionInfo);
}
addTheTablesInPartialState(this.disablingTables, this.enablingTables, regionInfo,
tableName);
}
}
return offlineServers;
}
private void addTheTablesInPartialState(Set<String> disablingTables,
Set<String> enablingTables, HRegionInfo regionInfo,
String disablingTableName) {
if (checkIfRegionBelongsToDisabling(regionInfo)) {
disablingTables.add(disablingTableName);
} else if (checkIfRegionsBelongsToEnabling(regionInfo)) {
enablingTables.add(disablingTableName);
}
}
/**
* Recover the tables that were not fully moved to DISABLED state. These
* tables are in DISABLING state when the master restarted/switched.
*
* @param disablingTables
* @return
* @throws KeeperException
* @throws TableNotFoundException
* @throws IOException
*/
private boolean recoverTableInDisablingState(Set<String> disablingTables)
throws KeeperException, TableNotFoundException, IOException {
boolean isWatcherCreated = false;
if (disablingTables.size() != 0) {
// Create a watcher on the zookeeper node
ZKUtil.listChildrenAndWatchForNewChildren(watcher,
watcher.assignmentZNode);
isWatcherCreated = true;
for (String tableName : disablingTables) {
// Recover by calling DisableTableHandler
LOG.info("The table " + tableName
+ " is in DISABLING state. Hence recovering by moving the table"
+ " to DISABLED state.");
new DisableTableHandler(this.master, tableName.getBytes(),
catalogTracker, this, true).process();
}
}
return isWatcherCreated;
}
/**
* Recover the tables that are not fully moved to ENABLED state. These tables
* are in ENABLING state when the master restarted/switched
*
* @param enablingTables
* @param isWatcherCreated
* @throws KeeperException
* @throws TableNotFoundException
* @throws IOException
*/
private void recoverTableInEnablingState(Set<String> enablingTables,
boolean isWatcherCreated) throws KeeperException, TableNotFoundException,
IOException {
if (enablingTables.size() != 0) {
if (false == isWatcherCreated) {
ZKUtil.listChildrenAndWatchForNewChildren(watcher,
watcher.assignmentZNode);
}
for (String tableName : enablingTables) {
// Recover by calling EnableTableHandler
LOG.info("The table " + tableName
+ " is in ENABLING state. Hence recovering by moving the table"
+ " to ENABLED state.");
// enableTable in sync way during master startup,
// no need to invoke coprocessor
new EnableTableHandler(this.master, tableName.getBytes(),
catalogTracker, this, true).process();
}
}
}
private boolean checkIfRegionsBelongsToEnabling(HRegionInfo regionInfo) {
String tableName = regionInfo.getTableNameAsString();
return getZKTable().isEnablingTable(tableName);
}
private boolean checkIfRegionBelongsToDisabled(HRegionInfo regionInfo) {
String tableName = regionInfo.getTableNameAsString();
return getZKTable().isDisabledTable(tableName);
}
private boolean checkIfRegionBelongsToDisabling(HRegionInfo regionInfo) {
String tableName = regionInfo.getTableNameAsString();
return getZKTable().isDisablingTable(tableName);
}
/**
* Processes list of dead servers from result of META scan and regions in RIT
* <p>
* This is used for failover to recover the lost regions that belonged to
* RegionServers which failed while there was no active master or regions
* that were in RIT.
* <p>
*
* @param deadServers
* The list of dead servers which failed while there was no active
* master. Can be null.
* @param nodes
* The regions in RIT
* @throws IOException
* @throws KeeperException
*/
private void processDeadServersAndRecoverLostRegions(
Map<ServerName, List<Pair<HRegionInfo, Result>>> deadServers,
List<String> nodes) throws IOException, KeeperException {
if (null != deadServers) {
for (Map.Entry<ServerName, List<Pair<HRegionInfo, Result>>> deadServer :
deadServers.entrySet()) {
List<Pair<HRegionInfo, Result>> regions = deadServer.getValue();
for (Pair<HRegionInfo, Result> region : regions) {
HRegionInfo regionInfo = region.getFirst();
Result result = region.getSecond();
// If region was in transition (was in zk) force it offline for
// reassign
try {
RegionTransitionData data = ZKAssign.getData(watcher,
regionInfo.getEncodedName());
// If zk node of this region has been updated by a live server,
// we consider that this region is being handled.
// So we should skip it and process it in
// processRegionsInTransition.
if (data != null && data.getOrigin() != null &&
serverManager.isServerOnline(data.getOrigin())) {
LOG.info("The region " + regionInfo.getEncodedName()
+ "is being handled on " + data.getOrigin());
continue;
}
// Process with existing RS shutdown code
boolean assign = ServerShutdownHandler.processDeadRegion(
regionInfo, result, this, this.catalogTracker);
if (assign) {
ZKAssign.createOrForceNodeOffline(watcher, regionInfo,
master.getServerName());
if (!nodes.contains(regionInfo.getEncodedName())) {
nodes.add(regionInfo.getEncodedName());
}
}
} catch (KeeperException.NoNodeException nne) {
// This is fine
}
}
}
}
if (!nodes.isEmpty()) {
for (String encodedRegionName : nodes) {
processRegionInTransition(encodedRegionName, null, deadServers);
}
}
}
/*
* Presumes caller has taken care of necessary locking modifying servers Map.
* @param hsi
* @param hri
*/
private void addToServers(final ServerName sn, final HRegionInfo hri) {
Set<HRegionInfo> hris = servers.get(sn);
if (hris == null) {
hris = new ConcurrentSkipListSet<HRegionInfo>();
servers.put(sn, hris);
}
if (!hris.contains(hri)) hris.add(hri);
}
/**
* @return A copy of the Map of regions currently in transition.
*/
public NavigableMap<String, RegionState> getRegionsInTransition() {
synchronized (this.regionsInTransition) {
return new TreeMap<String, RegionState>(this.regionsInTransition);
}
}
/**
* @return True if regions in transition.
*/
public boolean isRegionsInTransition() {
synchronized (this.regionsInTransition) {
return !this.regionsInTransition.isEmpty();
}
}
/**
* @param hri Region to check.
* @return Returns null if passed region is not in transition else the current
* RegionState
*/
public RegionState isRegionInTransition(final HRegionInfo hri) {
synchronized (this.regionsInTransition) {
return this.regionsInTransition.get(hri.getEncodedName());
}
}
/**
* Clears the specified region from being in transition.
* @param hri Region to remove.
*/
public void clearRegionFromTransition(HRegionInfo hri) {
synchronized (this.regionsInTransition) {
this.regionsInTransition.remove(hri.getEncodedName());
}
synchronized (this.regions) {
this.regions.remove(hri);
for (Set<HRegionInfo> regions : this.servers.values()) {
regions.remove(hri);
}
}
clearRegionPlan(hri);
}
/**
* @param region Region whose plan we are to clear.
*/
void clearRegionPlan(final HRegionInfo region) {
synchronized (this.regionPlans) {
this.regionPlans.remove(region.getEncodedName());
}
}
/**
* Wait on region to clear regions-in-transition.
* @param hri Region to wait on.
* @throws IOException
*/
public void waitOnRegionToClearRegionsInTransition(final HRegionInfo hri)
throws IOException {
if (isRegionInTransition(hri) == null) return;
RegionState rs = null;
// There is already a timeout monitor on regions in transition so I
// should not have to have one here too?
while(!this.master.isStopped() && (rs = isRegionInTransition(hri)) != null) {
Threads.sleep(1000);
LOG.info("Waiting on " + rs + " to clear regions-in-transition");
}
if (this.master.isStopped()) {
LOG.info("Giving up wait on regions in " +
"transition because stoppable.isStopped is set");
}
}
/**
* Gets the online regions of the specified table.
* This method looks at the in-memory state. It does not go to <code>.META.</code>.
* Only returns <em>online</em> regions. If a region on this table has been
* closed during a disable, etc., it will be included in the returned list.
* So, the returned list may not necessarily be ALL regions in this table, its
* all the ONLINE regions in the table.
* @param tableName
* @return Online regions from <code>tableName</code>
*/
public List<HRegionInfo> getRegionsOfTable(byte[] tableName) {
List<HRegionInfo> tableRegions = new ArrayList<HRegionInfo>();
HRegionInfo boundary =
new HRegionInfo(tableName, null, null);
synchronized (this.regions) {
for (HRegionInfo regionInfo: this.regions.tailMap(boundary).keySet()) {
if(Bytes.equals(regionInfo.getTableName(), tableName)) {
tableRegions.add(regionInfo);
} else {
break;
}
}
}
return tableRegions;
}
/**
* Monitor to check for time outs on region transition operations
*/
public class TimeoutMonitor extends Chore {
private final int timeout;
private boolean bulkAssign = false;
private boolean allRegionServersOffline = false;
private ServerManager serverManager;
/**
* Creates a periodic monitor to check for time outs on region transition
* operations. This will deal with retries if for some reason something
* doesn't happen within the specified timeout.
* @param period
* @param stopper When {@link Stoppable#isStopped()} is true, this thread will
* cleanup and exit cleanly.
* @param timeout
*/
public TimeoutMonitor(final int period, final Stoppable stopper,
ServerManager serverManager,
final int timeout) {
super("AssignmentTimeoutMonitor", period, stopper);
this.timeout = timeout;
this.serverManager = serverManager;
}
/**
* @param bulkAssign If true, we'll suspend checking regions in transition
* up in zookeeper. If false, will reenable check.
* @return Old setting for bulkAssign.
*/
public boolean bulkAssign(final boolean bulkAssign) {
boolean result = this.bulkAssign;
this.bulkAssign = bulkAssign;
return result;
}
private synchronized void setAllRegionServersOffline(
boolean allRegionServersOffline) {
this.allRegionServersOffline = allRegionServersOffline;
}
@Override
protected void chore() {
// If bulkAssign in progress, suspend checks
if (this.bulkAssign) return;
boolean allRSsOffline = this.serverManager.getOnlineServersList().
isEmpty();
synchronized (regionsInTransition) {
// Iterate all regions in transition checking for time outs
long now = System.currentTimeMillis();
for (RegionState regionState : regionsInTransition.values()) {
if (regionState.getStamp() + timeout <= now) {
//decide on action upon timeout
actOnTimeOut(regionState);
} else if (this.allRegionServersOffline && !allRSsOffline) {
// if some RSs just came back online, we can start the
// the assignment right away
actOnTimeOut(regionState);
}
}
}
setAllRegionServersOffline(allRSsOffline);
}
private void actOnTimeOut(RegionState regionState) {
HRegionInfo regionInfo = regionState.getRegion();
LOG.info("Regions in transition timed out: " + regionState);
// Expired! Do a retry.
switch (regionState.getState()) {
case CLOSED:
LOG.info("Region " + regionInfo.getEncodedName()
+ " has been CLOSED for too long, waiting on queued "
+ "ClosedRegionHandler to run or server shutdown");
// Update our timestamp.
regionState.updateTimestampToNow();
break;
case OFFLINE:
LOG.info("Region has been OFFLINE for too long, " + "reassigning "
+ regionInfo.getRegionNameAsString() + " to a random server");
invokeAssign(regionInfo);
break;
case PENDING_OPEN:
LOG.info("Region has been PENDING_OPEN for too "
+ "long, reassigning region=" + regionInfo.getRegionNameAsString());
invokeAssign(regionInfo);
break;
case OPENING:
processOpeningState(regionInfo);
break;
case OPEN:
LOG.error("Region has been OPEN for too long, " +
"we don't know where region was opened so can't do anything");
synchronized (regionState) {
regionState.updateTimestampToNow();
}
break;
case PENDING_CLOSE:
LOG.info("Region has been PENDING_CLOSE for too "
+ "long, running forced unassign again on region="
+ regionInfo.getRegionNameAsString());
invokeUnassign(regionInfo);
break;
case CLOSING:
LOG.info("Region has been CLOSING for too " +
"long, this should eventually complete or the server will " +
"expire, send RPC again");
invokeUnassign(regionInfo);
break;
}
}
}
private void processOpeningState(HRegionInfo regionInfo) {
LOG.info("Region has been OPENING for too " + "long, reassigning region="
+ regionInfo.getRegionNameAsString());
// Should have a ZK node in OPENING state
try {
String node = ZKAssign.getNodeName(watcher, regionInfo.getEncodedName());
Stat stat = new Stat();
RegionTransitionData dataInZNode = ZKAssign.getDataNoWatch(watcher, node,
stat);
if (dataInZNode == null) {
LOG.warn("Data is null, node " + node + " no longer exists");
return;
}
if (dataInZNode.getEventType() == EventType.RS_ZK_REGION_OPENED) {
LOG.debug("Region has transitioned to OPENED, allowing "
+ "watched event handlers to process");
return;
} else if (dataInZNode.getEventType() != EventType.RS_ZK_REGION_OPENING &&
dataInZNode.getEventType() != EventType.RS_ZK_REGION_FAILED_OPEN ) {
LOG.warn("While timing out a region in state OPENING, "
+ "found ZK node in unexpected state: "
+ dataInZNode.getEventType());
return;
}
invokeAssign(regionInfo);
} catch (KeeperException ke) {
LOG.error("Unexpected ZK exception timing out CLOSING region", ke);
return;
}
return;
}
private void invokeAssign(HRegionInfo regionInfo) {
threadPoolExecutorService.submit(new AssignCallable(this, regionInfo));
}
private void invokeUnassign(HRegionInfo regionInfo) {
threadPoolExecutorService.submit(new UnAssignCallable(this, regionInfo));
}
public boolean isCarryingRoot(ServerName serverName) {
return isCarryingRegion(serverName, HRegionInfo.ROOT_REGIONINFO);
}
public boolean isCarryingMeta(ServerName serverName) {
return isCarryingRegion(serverName, HRegionInfo.FIRST_META_REGIONINFO);
}
/**
* Check if the shutdown server carries the specific region.
* We have a bunch of places that store region location
* Those values aren't consistent. There is a delay of notification.
* The location from zookeeper unassigned node has the most recent data;
* but the node could be deleted after the region is opened by AM.
* The AM's info could be old when OpenedRegionHandler
* processing hasn't finished yet when server shutdown occurs.
* @return whether the serverName currently hosts the region
*/
public boolean isCarryingRegion(ServerName serverName, HRegionInfo hri) {
RegionTransitionData data = null;
try {
data = ZKAssign.getData(master.getZooKeeper(), hri.getEncodedName());
} catch (KeeperException e) {
master.abort("Unexpected ZK exception reading unassigned node for region="
+ hri.getEncodedName(), e);
}
ServerName addressFromZK = (data != null && data.getOrigin() != null) ?
data.getOrigin() : null;
if (addressFromZK != null) {
// if we get something from ZK, we will use the data
boolean matchZK = (addressFromZK != null &&
addressFromZK.equals(serverName));
LOG.debug("based on ZK, current region=" + hri.getRegionNameAsString() +
" is on server=" + addressFromZK +
" server being checked=: " + serverName);
return matchZK;
}
ServerName addressFromAM = getRegionServerOfRegion(hri);
boolean matchAM = (addressFromAM != null &&
addressFromAM.equals(serverName));
LOG.debug("based on AM, current region=" + hri.getRegionNameAsString() +
" is on server=" + (addressFromAM != null ? addressFromAM : "null") +
" server being checked: " + serverName);
return matchAM;
}
/**
* Process shutdown server removing any assignments.
* @param sn Server that went down.
* @return list of regions in transition on this server
*/
public List<RegionState> processServerShutdown(final ServerName sn) {
// Clean out any existing assignment plans for this server
synchronized (this.regionPlans) {
for (Iterator <Map.Entry<String, RegionPlan>> i =
this.regionPlans.entrySet().iterator(); i.hasNext();) {
Map.Entry<String, RegionPlan> e = i.next();
ServerName otherSn = e.getValue().getDestination();
// The name will be null if the region is planned for a random assign.
if (otherSn != null && otherSn.equals(sn)) {
// Use iterator's remove else we'll get CME
i.remove();
}
}
}
// TODO: Do we want to sync on RIT here?
// Remove this server from map of servers to regions, and remove all regions
// of this server from online map of regions.
Set<HRegionInfo> deadRegions = null;
List<RegionState> rits = new ArrayList<RegionState>();
synchronized (this.regions) {
Set<HRegionInfo> assignedRegions = this.servers.remove(sn);
if (assignedRegions == null || assignedRegions.isEmpty()) {
// No regions on this server, we are done, return empty list of RITs
return rits;
}
deadRegions = new TreeSet<HRegionInfo>(assignedRegions);
for (HRegionInfo region : deadRegions) {
this.regions.remove(region);
}
}
// See if any of the regions that were online on this server were in RIT
// If they are, normal timeouts will deal with them appropriately so
// let's skip a manual re-assignment.
synchronized (regionsInTransition) {
for (RegionState region : this.regionsInTransition.values()) {
if (deadRegions.remove(region.getRegion())) {
rits.add(region);
}
}
}
return rits;
}
/**
* Update inmemory structures.
* @param sn Server that reported the split
* @param parent Parent region that was split
* @param a Daughter region A
* @param b Daughter region B
*/
public void handleSplitReport(final ServerName sn, final HRegionInfo parent,
final HRegionInfo a, final HRegionInfo b) {
regionOffline(parent);
regionOnline(a, sn);
regionOnline(b, sn);
// There's a possibility that the region was splitting while a user asked
// the master to disable, we need to make sure we close those regions in
// that case. This is not racing with the region server itself since RS
// report is done after the split transaction completed.
if (this.zkTable.isDisablingOrDisabledTable(
parent.getTableNameAsString())) {
unassign(a);
unassign(b);
}
}
/**
* @return A clone of current assignments. Note, this is assignments only.
* If a new server has come in and it has no regions, it will not be included
* in the returned Map.
*/
Map<ServerName, List<HRegionInfo>> getAssignments() {
// This is an EXPENSIVE clone. Cloning though is the safest thing to do.
// Can't let out original since it can change and at least the loadbalancer
// wants to iterate this exported list. We need to synchronize on regions
// since all access to this.servers is under a lock on this.regions.
Map<ServerName, List<HRegionInfo>> result = null;
synchronized (this.regions) {
result = new HashMap<ServerName, List<HRegionInfo>>(this.servers.size());
for (Map.Entry<ServerName, Set<HRegionInfo>> e: this.servers.entrySet()) {
result.put(e.getKey(), new ArrayList<HRegionInfo>(e.getValue()));
}
}
return result;
}
/**
* @param encodedRegionName Region encoded name.
* @return Null or a {@link Pair} instance that holds the full {@link HRegionInfo}
* and the hosting servers {@link ServerName}.
*/
Pair<HRegionInfo, ServerName> getAssignment(final byte [] encodedRegionName) {
String name = Bytes.toString(encodedRegionName);
synchronized(this.regions) {
for (Map.Entry<HRegionInfo, ServerName> e: this.regions.entrySet()) {
if (e.getKey().getEncodedName().equals(name)) {
return new Pair<HRegionInfo, ServerName>(e.getKey(), e.getValue());
}
}
}
return null;
}
/**
* @param plan Plan to execute.
*/
void balance(final RegionPlan plan) {
synchronized (this.regionPlans) {
this.regionPlans.put(plan.getRegionName(), plan);
}
unassign(plan.getRegionInfo());
}
/**
* Run through remaining regionservers and unassign all catalog regions.
*/
void unassignCatalogRegions() {
this.servers.entrySet();
synchronized (this.regions) {
for (Map.Entry<ServerName, Set<HRegionInfo>> e: this.servers.entrySet()) {
Set<HRegionInfo> regions = e.getValue();
if (regions == null || regions.isEmpty()) continue;
for (HRegionInfo hri: regions) {
if (hri.isMetaRegion()) {
unassign(hri);
}
}
}
}
}
/**
* State of a Region while undergoing transitions.
*/
public static class RegionState implements org.apache.hadoop.io.Writable {
private HRegionInfo region;
public enum State {
OFFLINE, // region is in an offline state
PENDING_OPEN, // sent rpc to server to open but has not begun
OPENING, // server has begun to open but not yet done
OPEN, // server opened region and updated meta
PENDING_CLOSE, // sent rpc to server to close but has not begun
CLOSING, // server has begun to close but not yet done
CLOSED, // server closed region and updated meta
SPLITTING, // server started split of a region
SPLIT // server completed split of a region
}
private State state;
// Many threads can update the state at the stamp at the same time
private final AtomicLong stamp;
private ServerName serverName;
public RegionState() {
this.stamp = new AtomicLong(System.currentTimeMillis());
}
RegionState(HRegionInfo region, State state) {
this(region, state, System.currentTimeMillis(), null);
}
RegionState(HRegionInfo region, State state, long stamp, ServerName serverName) {
this.region = region;
this.state = state;
this.stamp = new AtomicLong(stamp);
this.serverName = serverName;
}
public void update(State state, long stamp, ServerName serverName) {
this.state = state;
updateTimestamp(stamp);
this.serverName = serverName;
}
public void update(State state) {
this.state = state;
updateTimestampToNow();
this.serverName = null;
}
public void updateTimestamp(long stamp) {
this.stamp.set(stamp);
}
public void updateTimestampToNow() {
this.stamp.set(System.currentTimeMillis());
}
public State getState() {
return state;
}
public long getStamp() {
return stamp.get();
}
public HRegionInfo getRegion() {
return region;
}
public boolean isClosing() {
return state == State.CLOSING;
}
public boolean isClosed() {
return state == State.CLOSED;
}
public boolean isPendingClose() {
return state == State.PENDING_CLOSE;
}
public boolean isOpening() {
return state == State.OPENING;
}
public boolean isOpened() {
return state == State.OPEN;
}
public boolean isPendingOpen() {
return state == State.PENDING_OPEN;
}
public boolean isOffline() {
return state == State.OFFLINE;
}
public boolean isSplitting() {
return state == State.SPLITTING;
}
public boolean isSplit() {
return state == State.SPLIT;
}
@Override
public String toString() {
return region.getRegionNameAsString()
+ " state=" + state
+ ", ts=" + stamp
+ ", server=" + serverName;
}
/**
* A slower (but more easy-to-read) stringification
*/
public String toDescriptiveString() {
long lstamp = stamp.get();
long relTime = System.currentTimeMillis() - lstamp;
return region.getRegionNameAsString()
+ " state=" + state
+ ", ts=" + new Date(lstamp) + " (" + (relTime/1000) + "s ago)"
+ ", server=" + serverName;
}
@Override
public void readFields(DataInput in) throws IOException {
region = new HRegionInfo();
region.readFields(in);
state = State.valueOf(in.readUTF());
stamp.set(in.readLong());
}
@Override
public void write(DataOutput out) throws IOException {
region.write(out);
out.writeUTF(state.name());
out.writeLong(stamp.get());
}
}
public void stop() {
this.timeoutMonitor.interrupt();
}
/**
* Check whether the RegionServer is online.
* @param serverName
* @return True if online.
*/
public boolean isServerOnline(ServerName serverName) {
return this.serverManager.isServerOnline(serverName);
}
/**
* Shutdown the threadpool executor service
*/
public void shutdown() {
if (null != threadPoolExecutorService) {
this.threadPoolExecutorService.shutdown();
}
}
}