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/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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package org.apache.hadoop.hbase.master;

import static org.apache.hadoop.hbase.util.ConcurrentMapUtils.computeIfAbsent;

import java.io.IOException;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.CopyOnWriteArrayList;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.function.Predicate;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.ClockOutOfSyncException;
import org.apache.hadoop.hbase.HConstants;
import org.apache.hadoop.hbase.NotServingRegionException;
import org.apache.hadoop.hbase.RegionMetrics;
import org.apache.hadoop.hbase.ServerMetrics;
import org.apache.hadoop.hbase.ServerMetricsBuilder;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.YouAreDeadException;
import org.apache.hadoop.hbase.client.ClusterConnection;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.ipc.HBaseRpcController;
import org.apache.hadoop.hbase.ipc.RemoteWithExtrasException;
import org.apache.hadoop.hbase.ipc.RpcControllerFactory;
import org.apache.hadoop.hbase.monitoring.MonitoredTask;
import org.apache.hadoop.hbase.procedure2.Procedure;
import org.apache.hadoop.hbase.regionserver.HRegionServer;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
import org.apache.hadoop.hbase.zookeeper.ZKUtil;
import org.apache.hadoop.hbase.zookeeper.ZKWatcher;
import org.apache.hadoop.hbase.zookeeper.ZNodePaths;
import org.apache.yetus.audience.InterfaceAudience;
import org.apache.zookeeper.KeeperException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import org.apache.hbase.thirdparty.com.google.protobuf.UnsafeByteOperations;

import org.apache.hadoop.hbase.shaded.protobuf.ProtobufUtil;
import org.apache.hadoop.hbase.shaded.protobuf.generated.AdminProtos.AdminService;
import org.apache.hadoop.hbase.shaded.protobuf.generated.ClusterStatusProtos.RegionStoreSequenceIds;
import org.apache.hadoop.hbase.shaded.protobuf.generated.ClusterStatusProtos.StoreSequenceId;
import org.apache.hadoop.hbase.shaded.protobuf.generated.RegionServerStatusProtos.RegionServerStartupRequest;

/**
 * The ServerManager class manages info about region servers.
 * 

* Maintains lists of online and dead servers. Processes the startups, shutdowns, and deaths of * region servers. *

* Servers are distinguished in two different ways. A given server has a location, specified by * hostname and port, and of which there can only be one online at any given time. A server instance * is specified by the location (hostname and port) as well as the startcode (timestamp from when * the server was started). This is used to differentiate a restarted instance of a given server * from the original instance. *

* If a sever is known not to be running any more, it is called dead. The dead server needs to be * handled by a ServerShutdownHandler. If the handler is not enabled yet, the server can't be * handled right away so it is queued up. After the handler is enabled, the server will be submitted * to a handler to handle. However, the handler may be just partially enabled. If so, the server * cannot be fully processed, and be queued up for further processing. A server is fully processed * only after the handler is fully enabled and has completed the handling. */ @InterfaceAudience.Private public class ServerManager { public static final String WAIT_ON_REGIONSERVERS_MAXTOSTART = "hbase.master.wait.on.regionservers.maxtostart"; public static final String WAIT_ON_REGIONSERVERS_MINTOSTART = "hbase.master.wait.on.regionservers.mintostart"; public static final String WAIT_ON_REGIONSERVERS_TIMEOUT = "hbase.master.wait.on.regionservers.timeout"; public static final String WAIT_ON_REGIONSERVERS_INTERVAL = "hbase.master.wait.on.regionservers.interval"; private static final Logger LOG = LoggerFactory.getLogger(ServerManager.class); // Set if we are to shutdown the cluster. private AtomicBoolean clusterShutdown = new AtomicBoolean(false); /** * The last flushed sequence id for a region. */ private final ConcurrentNavigableMap flushedSequenceIdByRegion = new ConcurrentSkipListMap<>(Bytes.BYTES_COMPARATOR); /** * The last flushed sequence id for a store in a region. */ private final ConcurrentNavigableMap> storeFlushedSequenceIdsByRegion = new ConcurrentSkipListMap<>(Bytes.BYTES_COMPARATOR); /** Map of registered servers to their current load */ private final ConcurrentNavigableMap onlineServers = new ConcurrentSkipListMap<>(); /** List of region servers that should not get any more new regions. */ private final ArrayList drainingServers = new ArrayList<>(); private final MasterServices master; private final ClusterConnection connection; private final RegionServerList storage; private final DeadServer deadservers = new DeadServer(); private final long maxSkew; private final long warningSkew; private final RpcControllerFactory rpcControllerFactory; /** Listeners that are called on server events. */ private List listeners = new CopyOnWriteArrayList<>(); /** * Constructor. */ public ServerManager(final MasterServices master, RegionServerList storage) { this.master = master; this.storage = storage; Configuration c = master.getConfiguration(); maxSkew = c.getLong("hbase.master.maxclockskew", 30000); warningSkew = c.getLong("hbase.master.warningclockskew", 10000); this.connection = master.getClusterConnection(); this.rpcControllerFactory = this.connection == null ? null : connection.getRpcControllerFactory(); } /** * Add the listener to the notification list. * @param listener The ServerListener to register */ public void registerListener(final ServerListener listener) { this.listeners.add(listener); } /** * Remove the listener from the notification list. * @param listener The ServerListener to unregister */ public boolean unregisterListener(final ServerListener listener) { return this.listeners.remove(listener); } /** * Let the server manager know a new regionserver has come online * @param request the startup request * @param versionNumber the version number of the new regionserver * @param version the version of the new regionserver, could contain strings like "SNAPSHOT" * @param ia the InetAddress from which request is received * @return The ServerName we know this server as. */ ServerName regionServerStartup(RegionServerStartupRequest request, int versionNumber, String version, InetAddress ia) throws IOException { // Test for case where we get a region startup message from a regionserver // that has been quickly restarted but whose znode expiration handler has // not yet run, or from a server whose fail we are currently processing. // Test its host+port combo is present in serverAddressToServerInfo. If it // is, reject the server and trigger its expiration. The next time it comes // in, it should have been removed from serverAddressToServerInfo and queued // for processing by ProcessServerShutdown. final String hostname = request.hasUseThisHostnameInstead() ? request.getUseThisHostnameInstead() : ia.getHostName(); ServerName sn = ServerName.valueOf(hostname, request.getPort(), request.getServerStartCode()); checkClockSkew(sn, request.getServerCurrentTime()); checkIsDead(sn, "STARTUP"); if (!checkAndRecordNewServer(sn, ServerMetricsBuilder.of(sn, versionNumber, version))) { LOG.warn( "THIS SHOULD NOT HAPPEN, RegionServerStartup" + " could not record the server: " + sn); } storage.started(sn); return sn; } /** * Updates last flushed sequence Ids for the regions on server sn */ private void updateLastFlushedSequenceIds(ServerName sn, ServerMetrics hsl) { for (Entry entry : hsl.getRegionMetrics().entrySet()) { byte[] encodedRegionName = Bytes.toBytes(RegionInfo.encodeRegionName(entry.getKey())); Long existingValue = flushedSequenceIdByRegion.get(encodedRegionName); long l = entry.getValue().getCompletedSequenceId(); // Don't let smaller sequence ids override greater sequence ids. if (LOG.isTraceEnabled()) { LOG.trace(Bytes.toString(encodedRegionName) + ", existingValue=" + existingValue + ", completeSequenceId=" + l); } if (existingValue == null || (l != HConstants.NO_SEQNUM && l > existingValue)) { flushedSequenceIdByRegion.put(encodedRegionName, l); } else if (l != HConstants.NO_SEQNUM && l < existingValue) { LOG.warn("RegionServer " + sn + " indicates a last flushed sequence id (" + l + ") that is less than the previous last flushed sequence id (" + existingValue + ") for region " + Bytes.toString(entry.getKey()) + " Ignoring."); } ConcurrentNavigableMap storeFlushedSequenceId = computeIfAbsent(storeFlushedSequenceIdsByRegion, encodedRegionName, () -> new ConcurrentSkipListMap<>(Bytes.BYTES_COMPARATOR)); for (Entry storeSeqId : entry.getValue().getStoreSequenceId().entrySet()) { byte[] family = storeSeqId.getKey(); existingValue = storeFlushedSequenceId.get(family); l = storeSeqId.getValue(); if (LOG.isTraceEnabled()) { LOG.trace(Bytes.toString(encodedRegionName) + ", family=" + Bytes.toString(family) + ", existingValue=" + existingValue + ", completeSequenceId=" + l); } // Don't let smaller sequence ids override greater sequence ids. if (existingValue == null || (l != HConstants.NO_SEQNUM && l > existingValue.longValue())) { storeFlushedSequenceId.put(family, l); } } } } public void regionServerReport(ServerName sn, ServerMetrics sl) throws YouAreDeadException { checkIsDead(sn, "REPORT"); if (null == this.onlineServers.replace(sn, sl)) { // Already have this host+port combo and its just different start code? // Just let the server in. Presume master joining a running cluster. // recordNewServer is what happens at the end of reportServerStartup. // The only thing we are skipping is passing back to the regionserver // the ServerName to use. Here we presume a master has already done // that so we'll press on with whatever it gave us for ServerName. if (!checkAndRecordNewServer(sn, sl)) { LOG.info("RegionServerReport ignored, could not record the server: " + sn); return; // Not recorded, so no need to move on } } updateLastFlushedSequenceIds(sn, sl); } /** * Check is a server of same host and port already exists, if not, or the existed one got a * smaller start code, record it. * @param serverName the server to check and record * @param sl the server load on the server * @return true if the server is recorded, otherwise, false */ boolean checkAndRecordNewServer(final ServerName serverName, final ServerMetrics sl) { ServerName existingServer = null; synchronized (this.onlineServers) { existingServer = findServerWithSameHostnamePortWithLock(serverName); if (existingServer != null && (existingServer.getStartcode() > serverName.getStartcode())) { LOG.info("Server serverName=" + serverName + " rejected; we already have " + existingServer.toString() + " registered with same hostname and port"); return false; } recordNewServerWithLock(serverName, sl); } // Tell our listeners that a server was added if (!this.listeners.isEmpty()) { for (ServerListener listener : this.listeners) { listener.serverAdded(serverName); } } // Note that we assume that same ts means same server, and don't expire in that case. // TODO: ts can theoretically collide due to clock shifts, so this is a bit hacky. if (existingServer != null && (existingServer.getStartcode() < serverName.getStartcode())) { LOG.info("Triggering server recovery; existingServer " + existingServer + " looks stale, new server:" + serverName); expireServer(existingServer); } return true; } /** * Find out the region servers crashed between the crash of the previous master instance and the * current master instance and schedule SCP for them. *

* Since the {@code RegionServerTracker} has already helped us to construct the online servers set * by scanning zookeeper, now we can compare the online servers with {@code liveServersFromWALDir} * to find out whether there are servers which are already dead. *

* Must be called inside the initialization method of {@code RegionServerTracker} to avoid * concurrency issue. * @param deadServersFromPE the region servers which already have a SCP associated. * @param liveServersFromWALDir the live region servers from wal directory. */ void findDeadServersAndProcess(Set deadServersFromPE, Set liveServersFromWALDir) { deadServersFromPE.forEach(deadservers::putIfAbsent); liveServersFromWALDir.stream().filter(sn -> !onlineServers.containsKey(sn)) .forEach(this::expireServer); } /** * Checks if the clock skew between the server and the master. If the clock skew exceeds the * configured max, it will throw an exception; if it exceeds the configured warning threshold, it * will log a warning but start normally. * @param serverName Incoming servers's name * @throws ClockOutOfSyncException if the skew exceeds the configured max value */ private void checkClockSkew(final ServerName serverName, final long serverCurrentTime) throws ClockOutOfSyncException { long skew = Math.abs(EnvironmentEdgeManager.currentTime() - serverCurrentTime); if (skew > maxSkew) { String message = "Server " + serverName + " has been " + "rejected; Reported time is too far out of sync with master. " + "Time difference of " + skew + "ms > max allowed of " + maxSkew + "ms"; LOG.warn(message); throw new ClockOutOfSyncException(message); } else if (skew > warningSkew) { String message = "Reported time for server " + serverName + " is out of sync with master " + "by " + skew + "ms. (Warning threshold is " + warningSkew + "ms; " + "error threshold is " + maxSkew + "ms)"; LOG.warn(message); } } /** * Called when RegionServer first reports in for duty and thereafter each time it heartbeats to * make sure it is has not been figured for dead. If this server is on the dead list, reject it * with a YouAreDeadException. If it was dead but came back with a new start code, remove the old * entry from the dead list. * @param what START or REPORT */ private void checkIsDead(final ServerName serverName, final String what) throws YouAreDeadException { if (this.deadservers.isDeadServer(serverName)) { // Exact match: host name, port and start code all match with existing one of the // dead servers. So, this server must be dead. Tell it to kill itself. String message = "Server " + what + " rejected; currently processing " + serverName + " as dead server"; LOG.debug(message); throw new YouAreDeadException(message); } // Remove dead server with same hostname and port of newly checking in rs after master // initialization. See HBASE-5916 for more information. if ( (this.master == null || this.master.isInitialized()) && this.deadservers.cleanPreviousInstance(serverName) ) { // This server has now become alive after we marked it as dead. // We removed it's previous entry from the dead list to reflect it. LOG.debug("{} {} came back up, removed it from the dead servers list", what, serverName); } } /** * Assumes onlineServers is locked. * @return ServerName with matching hostname and port. */ private ServerName findServerWithSameHostnamePortWithLock(final ServerName serverName) { ServerName end = ServerName.valueOf(serverName.getHostname(), serverName.getPort(), Long.MAX_VALUE); ServerName r = onlineServers.lowerKey(end); if (r != null) { if (ServerName.isSameAddress(r, serverName)) { return r; } } return null; } /** * Adds the onlineServers list. onlineServers should be locked. * @param serverName The remote servers name. */ void recordNewServerWithLock(final ServerName serverName, final ServerMetrics sl) { LOG.info("Registering regionserver=" + serverName); this.onlineServers.put(serverName, sl); } public RegionStoreSequenceIds getLastFlushedSequenceId(byte[] encodedRegionName) { RegionStoreSequenceIds.Builder builder = RegionStoreSequenceIds.newBuilder(); Long seqId = flushedSequenceIdByRegion.get(encodedRegionName); builder.setLastFlushedSequenceId(seqId != null ? seqId.longValue() : HConstants.NO_SEQNUM); Map storeFlushedSequenceId = storeFlushedSequenceIdsByRegion.get(encodedRegionName); if (storeFlushedSequenceId != null) { for (Map.Entry entry : storeFlushedSequenceId.entrySet()) { builder.addStoreSequenceId(StoreSequenceId.newBuilder() .setFamilyName(UnsafeByteOperations.unsafeWrap(entry.getKey())) .setSequenceId(entry.getValue().longValue()).build()); } } return builder.build(); } /** Returns ServerMetrics if serverName is known else null */ public ServerMetrics getLoad(final ServerName serverName) { return this.onlineServers.get(serverName); } /** * 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 */ public double getAverageLoad() { int totalLoad = 0; int numServers = 0; for (ServerMetrics sl : this.onlineServers.values()) { numServers++; totalLoad += sl.getRegionMetrics().size(); } return numServers == 0 ? 0 : (double) totalLoad / (double) numServers; } /** Returns the count of active regionservers */ public int countOfRegionServers() { // Presumes onlineServers is a concurrent map return this.onlineServers.size(); } /** Returns Read-only map of servers to serverinfo */ public Map getOnlineServers() { // Presumption is that iterating the returned Map is OK. synchronized (this.onlineServers) { return Collections.unmodifiableMap(this.onlineServers); } } public DeadServer getDeadServers() { return this.deadservers; } /** * Checks if any dead servers are currently in progress. * @return true if any RS are being processed as dead, false if not */ public boolean areDeadServersInProgress() { return this.deadservers.areDeadServersInProgress(); } void letRegionServersShutdown() { long previousLogTime = 0; ServerName sn = master.getServerName(); ZKWatcher zkw = master.getZooKeeper(); int onlineServersCt; while ((onlineServersCt = onlineServers.size()) > 0) { if (EnvironmentEdgeManager.currentTime() > (previousLogTime + 1000)) { Set remainingServers = onlineServers.keySet(); synchronized (onlineServers) { if (remainingServers.size() == 1 && remainingServers.contains(sn)) { // Master will delete itself later. return; } } StringBuilder sb = new StringBuilder(); // It's ok here to not sync on onlineServers - merely logging for (ServerName key : remainingServers) { if (sb.length() > 0) { sb.append(", "); } sb.append(key); } LOG.info("Waiting on regionserver(s) " + sb.toString()); previousLogTime = EnvironmentEdgeManager.currentTime(); } try { List servers = getRegionServersInZK(zkw); if ( servers == null || servers.isEmpty() || (servers.size() == 1 && servers.contains(sn.toString())) ) { LOG.info("ZK shows there is only the master self online, exiting now"); // Master could have lost some ZK events, no need to wait more. break; } } catch (KeeperException ke) { LOG.warn("Failed to list regionservers", ke); // ZK is malfunctioning, don't hang here break; } synchronized (onlineServers) { try { if (onlineServersCt == onlineServers.size()) onlineServers.wait(100); } catch (InterruptedException ignored) { // continue } } } } private List getRegionServersInZK(final ZKWatcher zkw) throws KeeperException { return ZKUtil.listChildrenNoWatch(zkw, zkw.getZNodePaths().rsZNode); } /** * Expire the passed server. Add it to list of dead servers and queue a shutdown processing. * @return pid if we queued a ServerCrashProcedure else {@link Procedure#NO_PROC_ID} if we did not * (could happen for many reasons including the fact that its this server that is going * down or we already have queued an SCP for this server or SCP processing is currently * disabled because we are in startup phase). */ // Redo test so we can make this protected. public synchronized long expireServer(final ServerName serverName) { return expireServer(serverName, false); } synchronized long expireServer(final ServerName serverName, boolean force) { // THIS server is going down... can't handle our own expiration. if (serverName.equals(master.getServerName())) { if (!(master.isAborted() || master.isStopped())) { master.stop("We lost our znode?"); } return Procedure.NO_PROC_ID; } if (this.deadservers.isDeadServer(serverName)) { LOG.warn("Expiration called on {} but already in DeadServer", serverName); return Procedure.NO_PROC_ID; } moveFromOnlineToDeadServers(serverName); // If server is in draining mode, remove corresponding znode // In some tests, the mocked HM may not have ZK Instance, hence null check if (master.getZooKeeper() != null) { String drainingZnode = ZNodePaths .joinZNode(master.getZooKeeper().getZNodePaths().drainingZNode, serverName.getServerName()); try { ZKUtil.deleteNodeFailSilent(master.getZooKeeper(), drainingZnode); } catch (KeeperException e) { LOG.warn( "Error deleting the draining znode for stopping server " + serverName.getServerName(), e); } } // If cluster is going down, yes, servers are going to be expiring; don't // process as a dead server if (isClusterShutdown()) { LOG.info("Cluster shutdown set; " + serverName + " expired; onlineServers=" + this.onlineServers.size()); if (this.onlineServers.isEmpty()) { master.stop("Cluster shutdown set; onlineServer=0"); } return Procedure.NO_PROC_ID; } LOG.info("Processing expiration of " + serverName + " on " + this.master.getServerName()); long pid = master.getAssignmentManager().submitServerCrash(serverName, true, force); storage.expired(serverName); // Tell our listeners that a server was removed if (!this.listeners.isEmpty()) { this.listeners.stream().forEach(l -> l.serverRemoved(serverName)); } return pid; } /** * Called when server has expired. */ // Locking in this class needs cleanup. public synchronized void moveFromOnlineToDeadServers(final ServerName sn) { synchronized (this.onlineServers) { boolean online = this.onlineServers.containsKey(sn); if (online) { // Remove the server from the known servers lists and update load info BUT // add to deadservers first; do this so it'll show in dead servers list if // not in online servers list. this.deadservers.putIfAbsent(sn); this.onlineServers.remove(sn); onlineServers.notifyAll(); } else { // If not online, that is odd but may happen if 'Unknown Servers' -- where meta // has references to servers not online nor in dead servers list. If // 'Unknown Server', don't add to DeadServers else will be there for ever. LOG.trace("Expiration of {} but server not online", sn); } } } /* * Remove the server from the drain list. */ public synchronized boolean removeServerFromDrainList(final ServerName sn) { // Warn if the server (sn) is not online. ServerName is of the form: // , , if (!this.isServerOnline(sn)) { LOG.warn("Server " + sn + " is not currently online. " + "Removing from draining list anyway, as requested."); } // Remove the server from the draining servers lists. return this.drainingServers.remove(sn); } /** * Add the server to the drain list. * @return True if the server is added or the server is already on the drain list. */ public synchronized boolean addServerToDrainList(final ServerName sn) { // Warn if the server (sn) is not online. ServerName is of the form: // , , if (!this.isServerOnline(sn)) { LOG.warn("Server " + sn + " is not currently online. " + "Ignoring request to add it to draining list."); return false; } // Add the server to the draining servers lists, if it's not already in // it. if (this.drainingServers.contains(sn)) { LOG.warn("Server " + sn + " is already in the draining server list." + "Ignoring request to add it again."); return true; } LOG.info("Server " + sn + " added to draining server list."); return this.drainingServers.add(sn); } // RPC methods to region servers private HBaseRpcController newRpcController() { return rpcControllerFactory == null ? null : rpcControllerFactory.newController(); } /** * Sends a WARMUP RPC to the specified server to warmup the specified region. *

* A region server could reject the close request because it either does not have the specified * region or the region is being split. * @param server server to warmup a region * @param region region to warmup */ public void sendRegionWarmup(ServerName server, RegionInfo region) { if (server == null) return; try { AdminService.BlockingInterface admin = getRsAdmin(server); HBaseRpcController controller = newRpcController(); ProtobufUtil.warmupRegion(controller, admin, region); } catch (IOException e) { LOG.error("Received exception in RPC for warmup server:" + server + "region: " + region + "exception: " + e); } } /** * Contacts a region server and waits up to timeout ms to close the region. This bypasses the * active hmaster. Pass -1 as timeout if you do not want to wait on result. */ public static void closeRegionSilentlyAndWait(ClusterConnection connection, ServerName server, RegionInfo region, long timeout) throws IOException, InterruptedException { AdminService.BlockingInterface rs = connection.getAdmin(server); HBaseRpcController controller = connection.getRpcControllerFactory().newController(); try { ProtobufUtil.closeRegion(controller, rs, server, region.getRegionName()); } catch (IOException e) { LOG.warn("Exception when closing region: " + region.getRegionNameAsString(), e); } if (timeout < 0) { return; } long expiration = timeout + EnvironmentEdgeManager.currentTime(); while (EnvironmentEdgeManager.currentTime() < expiration) { controller.reset(); try { RegionInfo rsRegion = ProtobufUtil.getRegionInfo(controller, rs, region.getRegionName()); if (rsRegion == null) return; } catch (IOException ioe) { if ( ioe instanceof NotServingRegionException || (ioe instanceof RemoteWithExtrasException && ((RemoteWithExtrasException) ioe) .unwrapRemoteException() instanceof NotServingRegionException) ) { // no need to retry again return; } LOG.warn("Exception when retrieving regioninfo from: " + region.getRegionNameAsString(), ioe); } Thread.sleep(1000); } throw new IOException("Region " + region + " failed to close within" + " timeout " + timeout); } /** * @return Admin interface for the remote regionserver named sn * @throws RetriesExhaustedException wrapping a ConnectException if failed */ public AdminService.BlockingInterface getRsAdmin(final ServerName sn) throws IOException { LOG.debug("New admin connection to {}", sn); if (sn.equals(master.getServerName()) && master instanceof HRegionServer) { // A master is also a region server now, see HBASE-10569 for details return ((HRegionServer) master).getRSRpcServices(); } else { return this.connection.getAdmin(sn); } } /** * Calculate min necessary to start. This is not an absolute. It is just a friction that will * cause us hang around a bit longer waiting on RegionServers to check-in. */ private int getMinToStart() { if (master.isInMaintenanceMode()) { // If in maintenance mode, then master hosting meta will be the only server available return 1; } int minimumRequired = 1; if ( LoadBalancer.isTablesOnMaster(master.getConfiguration()) && LoadBalancer.isSystemTablesOnlyOnMaster(master.getConfiguration()) ) { // If Master is carrying regions it will show up as a 'server', but is not handling user- // space regions, so we need a second server. minimumRequired = 2; } int minToStart = this.master.getConfiguration().getInt(WAIT_ON_REGIONSERVERS_MINTOSTART, -1); // Ensure we are never less than minimumRequired else stuff won't work. return Math.max(minToStart, minimumRequired); } /** * Wait for the region servers to report in. We will wait until one of this condition is met: - * the master is stopped - the 'hbase.master.wait.on.regionservers.maxtostart' number of region * servers is reached - the 'hbase.master.wait.on.regionservers.mintostart' is reached AND there * have been no new region server in for 'hbase.master.wait.on.regionservers.interval' time AND * the 'hbase.master.wait.on.regionservers.timeout' is reached */ public void waitForRegionServers(MonitoredTask status) throws InterruptedException { final long interval = this.master.getConfiguration().getLong(WAIT_ON_REGIONSERVERS_INTERVAL, 1500); final long timeout = this.master.getConfiguration().getLong(WAIT_ON_REGIONSERVERS_TIMEOUT, 4500); // Min is not an absolute; just a friction making us wait longer on server checkin. int minToStart = getMinToStart(); int maxToStart = this.master.getConfiguration().getInt(WAIT_ON_REGIONSERVERS_MAXTOSTART, Integer.MAX_VALUE); if (maxToStart < minToStart) { LOG.warn(String.format("The value of '%s' (%d) is set less than '%s' (%d), ignoring.", WAIT_ON_REGIONSERVERS_MAXTOSTART, maxToStart, WAIT_ON_REGIONSERVERS_MINTOSTART, minToStart)); maxToStart = Integer.MAX_VALUE; } long now = EnvironmentEdgeManager.currentTime(); final long startTime = now; long slept = 0; long lastLogTime = 0; long lastCountChange = startTime; int count = countOfRegionServers(); int oldCount = 0; // This while test is a little hard to read. We try to comment it in below but in essence: // Wait if Master is not stopped and the number of regionservers that have checked-in is // less than the maxToStart. Both of these conditions will be true near universally. // Next, we will keep cycling if ANY of the following three conditions are true: // 1. The time since a regionserver registered is < interval (means servers are actively // checking in). // 2. We are under the total timeout. // 3. The count of servers is < minimum. for (ServerListener listener : this.listeners) { listener.waiting(); } while ( !this.master.isStopped() && !isClusterShutdown() && count < maxToStart && ((lastCountChange + interval) > now || timeout > slept || count < minToStart) ) { // Log some info at every interval time or if there is a change if (oldCount != count || lastLogTime + interval < now) { lastLogTime = now; String msg = "Waiting on regionserver count=" + count + "; waited=" + slept + "ms, expecting min=" + minToStart + " server(s), max=" + getStrForMax(maxToStart) + " server(s), " + "timeout=" + timeout + "ms, lastChange=" + (now - lastCountChange) + "ms"; LOG.info(msg); status.setStatus(msg); } // We sleep for some time final long sleepTime = 50; Thread.sleep(sleepTime); now = EnvironmentEdgeManager.currentTime(); slept = now - startTime; oldCount = count; count = countOfRegionServers(); if (count != oldCount) { lastCountChange = now; } } // Did we exit the loop because cluster is going down? if (isClusterShutdown()) { this.master.stop("Cluster shutdown"); } LOG.info("Finished waiting on RegionServer count=" + count + "; waited=" + slept + "ms," + " expected min=" + minToStart + " server(s), max=" + getStrForMax(maxToStart) + " server(s)," + " master is " + (this.master.isStopped() ? "stopped." : "running")); } private String getStrForMax(final int max) { return max == Integer.MAX_VALUE ? "NO_LIMIT" : Integer.toString(max); } /** Returns A copy of the internal list of online servers. */ public List getOnlineServersList() { // TODO: optimize the load balancer call so we don't need to make a new list // TODO: FIX. THIS IS POPULAR CALL. return new ArrayList<>(this.onlineServers.keySet()); } /** * @param keys The target server name * @param idleServerPredicator Evaluates the server on the given load * @return A copy of the internal list of online servers matched by the predicator */ public List getOnlineServersListWithPredicator(List keys, Predicate idleServerPredicator) { List names = new ArrayList<>(); if (keys != null && idleServerPredicator != null) { keys.forEach(name -> { ServerMetrics load = onlineServers.get(name); if (load != null) { if (idleServerPredicator.test(load)) { names.add(name); } } }); } return names; } /** Returns A copy of the internal list of draining servers. */ public List getDrainingServersList() { return new ArrayList<>(this.drainingServers); } public boolean isServerOnline(ServerName serverName) { return serverName != null && onlineServers.containsKey(serverName); } public enum ServerLiveState { LIVE, DEAD, UNKNOWN } /** Returns whether the server is online, dead, or unknown. */ public synchronized ServerLiveState isServerKnownAndOnline(ServerName serverName) { return onlineServers.containsKey(serverName) ? ServerLiveState.LIVE : (deadservers.isDeadServer(serverName) ? ServerLiveState.DEAD : ServerLiveState.UNKNOWN); } /** * Check if a server is known to be dead. A server can be online, or known to be dead, or unknown * to this manager (i.e, not online, not known to be dead either; it is simply not tracked by the * master any more, for example, a very old previous instance). */ public synchronized boolean isServerDead(ServerName serverName) { return serverName == null || deadservers.isDeadServer(serverName); } /** * Check if a server is unknown. A server can be online, or known to be dead, or unknown to this * manager (i.e, not online, not known to be dead either; it is simply not tracked by the master * any more, for example, a very old previous instance). */ public boolean isServerUnknown(ServerName serverName) { return serverName == null || (!onlineServers.containsKey(serverName) && !deadservers.isDeadServer(serverName)); } public void shutdownCluster() { String statusStr = "Cluster shutdown requested of master=" + this.master.getServerName(); LOG.info(statusStr); this.clusterShutdown.set(true); if (onlineServers.isEmpty()) { // we do not synchronize here so this may cause a double stop, but not a big deal master.stop("OnlineServer=0 right after cluster shutdown set"); } } public boolean isClusterShutdown() { return this.clusterShutdown.get(); } /** * Stop the ServerManager. */ public void stop() { // Nothing to do. } /** * Creates a list of possible destinations for a region. It contains the online servers, but not * the draining or dying servers. * @param serversToExclude can be null if there is no server to exclude */ public List createDestinationServersList(final List serversToExclude) { Set destServers = new HashSet<>(); onlineServers.forEach((sn, sm) -> { if (sm.getLastReportTimestamp() > 0) { // This means we have already called regionServerReport at leaset once, then let's include // this server for region assignment. This is an optimization to avoid assigning regions to // an uninitialized server. See HBASE-25032 for more details. destServers.add(sn); } }); if (serversToExclude != null) { destServers.removeAll(serversToExclude); } // Loop through the draining server list and remove them from the server list final List drainingServersCopy = getDrainingServersList(); destServers.removeAll(drainingServersCopy); return new ArrayList<>(destServers); } /** * Calls {@link #createDestinationServersList} without server to exclude. */ public List createDestinationServersList() { return createDestinationServersList(null); } /** * To clear any dead server with same host name and port of any online server */ void clearDeadServersWithSameHostNameAndPortOfOnlineServer() { for (ServerName serverName : getOnlineServersList()) { deadservers.cleanAllPreviousInstances(serverName); } } /** * Called by delete table and similar to notify the ServerManager that a region was removed. */ public void removeRegion(final RegionInfo regionInfo) { final byte[] encodedName = regionInfo.getEncodedNameAsBytes(); storeFlushedSequenceIdsByRegion.remove(encodedName); flushedSequenceIdByRegion.remove(encodedName); } public boolean isRegionInServerManagerStates(final RegionInfo hri) { final byte[] encodedName = hri.getEncodedNameAsBytes(); return (storeFlushedSequenceIdsByRegion.containsKey(encodedName) || flushedSequenceIdByRegion.containsKey(encodedName)); } /** * Called by delete table and similar to notify the ServerManager that a region was removed. */ public void removeRegions(final List regions) { for (RegionInfo hri : regions) { removeRegion(hri); } } /** * May return 0 when server is not online. */ public int getVersionNumber(ServerName serverName) { ServerMetrics serverMetrics = onlineServers.get(serverName); return serverMetrics != null ? serverMetrics.getVersionNumber() : 0; } /** * May return "0.0.0" when server is not online */ public String getVersion(ServerName serverName) { ServerMetrics serverMetrics = onlineServers.get(serverName); return serverMetrics != null ? serverMetrics.getVersion() : "0.0.0"; } public int getInfoPort(ServerName serverName) { ServerMetrics serverMetrics = onlineServers.get(serverName); return serverMetrics != null ? serverMetrics.getInfoServerPort() : 0; } }





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