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HBASE-30201 Skip system region moves during active transitions #8672

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HBASE-30201 Skip system region moves during active transitions #8672

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57 changes: 27 additions & 30 deletions hbase-server/src/main/java/org/apache/hadoop/hbase/master/assignment/AssignmentManager.java
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Original file line number Diff line number Diff line change
Expand Up @@ -695,9 +695,6 @@ public boolean isMetaLoaded() {
* </p>
*/
public void checkIfShouldMoveSystemRegionAsync() {
// TODO: Fix this thread. If a server is killed and a new one started, this thread thinks that
// it should 'move' the system tables from the old server to the new server but
// ServerCrashProcedure is on it; and it will take care of the assign without dataloss.
if (this.master.getServerManager().countOfRegionServers() <= 1) {
return;
}
Expand All @@ -711,37 +708,37 @@ public void checkIfShouldMoveSystemRegionAsync() {
try {
synchronized (checkIfShouldMoveSystemRegionLock) {
List<RegionPlan> plans = new ArrayList<>();
// TODO: I don't think this code does a good job if all servers in cluster have same
// version. It looks like it will schedule unnecessary moves.
for (ServerName server : getExcludedServersForSystemTable()) {
if (master.getServerManager().isServerDead(server)) {
// TODO: See HBASE-18494 and HBASE-18495. Though getExcludedServersForSystemTable()
// considers only online servers, the server could be queued for dead server
// processing. As region assignments for crashed server is handled by
// ServerCrashProcedure, do NOT handle them here. The goal is to handle this through
// regular flow of LoadBalancer as a favored node and not to have this special
// handling.
if (!master.getServerManager().isServerOnline(server)) {
// Leave regions on crashed servers to ServerCrashProcedure.
continue;
}
List<RegionInfo> regionsShouldMove = getSystemTables(server);
if (!regionsShouldMove.isEmpty()) {
for (RegionInfo regionInfo : regionsShouldMove) {
// null value for dest forces destination server to be selected by balancer
RegionPlan plan = new RegionPlan(regionInfo, server, null);
if (regionInfo.isMetaRegion()) {
// Must move meta region first.
LOG.info("Async MOVE of {} to newer Server={}", regionInfo.getEncodedName(),
server);
moveAsync(plan);
} else {
plans.add(plan);
}
}
for (RegionInfo regionInfo : getSystemTables(server)) {
// null value for dest forces destination server to be selected by balancer
plans.add(new RegionPlan(regionInfo, server, null));
}
}
// Submit meta moves before other system regions, and submit each plan only once.
plans.sort(Comparator.comparing(plan -> !plan.getRegionInfo().isMetaRegion()));
for (RegionPlan plan : plans) {
RegionStateNode regionNode = regionStates.getRegionStateNode(plan.getRegionInfo());
if (regionNode == null || !master.getServerManager().isServerOnline(plan.getSource())) {
continue;
}
for (RegionPlan plan : plans) {
LOG.info("Async MOVE of {} to newer Server={}", plan.getRegionInfo().getEncodedName(),
server);
moveAsync(plan);
if (regionNode.isTransitionScheduled()) {
LOG.debug("Skip system region move for {}; a transition is already scheduled",
regionNode);
continue;
}
try {
// balance checks the source location; preTransitCheck still guards against a
// transition starting after the check above.
if (balance(plan) != null) {
LOG.info("Async MOVE of {} from {} to a newer RegionServer",
plan.getRegionInfo().getEncodedName(), plan.getSource());
}
} catch (HBaseIOException e) {
LOG.warn("Failed system region move {}, skipping this plan", plan, e);
}
}
}
Expand Down
175 changes: 175 additions & 0 deletions ...server/src/test/java/org/apache/hadoop/hbase/master/assignment/TestMoveSystemRegions.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,175 @@
/*
* 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.assignment;

import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertFalse;
import static org.junit.jupiter.api.Assertions.assertSame;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.argThat;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.doCallRealMethod;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseIOException;
import org.apache.hadoop.hbase.ServerName;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.RegionInfo;
import org.apache.hadoop.hbase.client.RegionInfoBuilder;
import org.apache.hadoop.hbase.master.MasterServices;
import org.apache.hadoop.hbase.master.RegionPlan;
import org.apache.hadoop.hbase.master.RegionState.State;
import org.apache.hadoop.hbase.master.ServerManager;
import org.apache.hadoop.hbase.testclassification.MasterTests;
import org.apache.hadoop.hbase.testclassification.SmallTests;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Tag;
import org.junit.jupiter.api.Test;

@Tag(MasterTests.TAG)
@Tag(SmallTests.TAG)
public class TestMoveSystemRegions {

private static final ServerName OLD_SERVER = ServerName.valueOf("old", 16020, 1);
private static final ServerName OTHER_OLD_SERVER = ServerName.valueOf("other-old", 16020, 1);
private static final ServerName NEW_SERVER = ServerName.valueOf("new", 16020, 1);
private static final RegionInfo META = RegionInfoBuilder.FIRST_META_REGIONINFO;
private static final RegionInfo SYSTEM_REGION =
RegionInfoBuilder.newBuilder(TableName.valueOf("hbase:test")).build();

private AssignmentManager am;
private ServerManager serverManager;
private final List<RegionInfo> movedRegions = new ArrayList<>();

@BeforeEach
public void setUp() throws Exception {
MasterServices master = mock(MasterServices.class);
when(master.getConfiguration()).thenReturn(new Configuration(false));
serverManager = mock(ServerManager.class);
when(master.getServerManager()).thenReturn(serverManager);
when(serverManager.countOfRegionServers()).thenReturn(3);
when(serverManager.getOnlineServersList())
.thenReturn(List.of(OLD_SERVER, OTHER_OLD_SERVER, NEW_SERVER));
when(serverManager.isServerOnline(any())).thenReturn(true);
when(master.getRegionServerVersion(OLD_SERVER)).thenReturn("2.6.4");
when(master.getRegionServerVersion(OTHER_OLD_SERVER)).thenReturn("2.6.4");
when(master.getRegionServerVersion(NEW_SERVER)).thenReturn("4.0.0");
am = spy(new AssignmentManager(master, null));
doAnswer(invocation -> {
RegionPlan plan = invocation.getArgument(0);
movedRegions.add(plan.getRegionInfo());
return CompletableFuture.completedFuture(null);
}).when(am).moveAsync(any());
}

private RegionStateNode addRegion(RegionInfo region, ServerName server) {
RegionStateNode node = am.getRegionStates().getOrCreateRegionStateNode(region);
node.setState(State.OPEN);
node.setRegionLocation(server);
am.getRegionStates().createServer(server);
am.getRegionStates().addRegionToServer(node);
return node;
}

private void checkSystemRegions() throws Exception {
CompletableFuture<Thread> checker = new CompletableFuture<>();
doAnswer(invocation -> {
checker.complete(Thread.currentThread());
return invocation.callRealMethod();
}).when(am).getExcludedServersForSystemTable();
am.checkIfShouldMoveSystemRegionAsync();
Thread thread = checker.get(10, TimeUnit.SECONDS);
thread.join(TimeUnit.SECONDS.toMillis(10));
assertFalse(thread.isAlive(), "System region check did not finish");
}

@Test
public void testSkipMetaInTransition() throws Exception {
RegionStateNode meta = addRegion(META, OLD_SERVER);
meta.setState(State.OPENING);
TransitRegionStateProcedure recovery = mock(TransitRegionStateProcedure.class);
meta.setProcedure(recovery);
addRegion(SYSTEM_REGION, OLD_SERVER);
// Exercise the real preTransitCheck if the compatibility check tries to move meta.
doCallRealMethod().when(am).moveAsync(argThat(p -> p.getRegionInfo().isMetaRegion()));

checkSystemRegions();

assertEquals(List.of(SYSTEM_REGION), movedRegions);
assertSame(recovery, meta.getProcedure());
assertEquals(State.OPENING, meta.getState());
verify(am, never()).moveAsync(argThat(p -> p.getRegionInfo().isMetaRegion()));
}

@Test
public void testSubmitEachPlanOnceAndMetaFirst() throws Exception {
addRegion(SYSTEM_REGION, OLD_SERVER);
addRegion(META, OTHER_OLD_SERVER);

checkSystemRegions();

assertEquals(List.of(META, SYSTEM_REGION), movedRegions);
verify(am, times(2)).moveAsync(any());
}

@Test
public void testSkipOfflineSource() throws Exception {
addRegion(META, OLD_SERVER);
addRegion(SYSTEM_REGION, OTHER_OLD_SERVER);
// The online-server snapshot can become stale before we examine its regions.
when(serverManager.isServerOnline(OLD_SERVER)).thenReturn(false);

checkSystemRegions();

assertEquals(List.of(SYSTEM_REGION), movedRegions);
}

@Test
public void testSkipChangedRegionLocation() throws Exception {
RegionStateNode meta = addRegion(META, OLD_SERVER);
meta.setRegionLocation(NEW_SERVER);
addRegion(SYSTEM_REGION, OTHER_OLD_SERVER);

checkSystemRegions();

assertEquals(List.of(SYSTEM_REGION), movedRegions);
}

@Test
public void testContinueAfterMoveFailure() throws Exception {
addRegion(META, OLD_SERVER);
addRegion(SYSTEM_REGION, OLD_SERVER);
doThrow(new HBaseIOException("Region entered transition after the check")).when(am)
.moveAsync(argThat(p -> p.getRegionInfo().isMetaRegion()));

checkSystemRegions();

assertEquals(List.of(SYSTEM_REGION), movedRegions);
}
}
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