HBASE-26643 LoadBalancer should not return empty map (#4005)

Signed-off-by: Yulin Niu <niuyulin@apache.org>
This commit is contained in:
Duo Zhang 2022-01-07 23:50:37 +08:00 committed by GitHub
parent 436fb7875c
commit 443bf30a5d
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2 changed files with 164 additions and 2 deletions

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@ -164,7 +164,7 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
int numServers = servers == null ? 0 : servers.size();
if (numServers == 0) {
LOG.warn("Wanted to do round robin assignment but no servers to assign to");
return Collections.emptyMap();
return Collections.singletonMap(BOGUS_SERVER_NAME, new ArrayList<>(regions));
}
// TODO: instead of retainAssignment() and roundRobinAssignment(), we should just run the
@ -272,7 +272,7 @@ public abstract class BaseLoadBalancer implements LoadBalancer {
int numServers = servers == null ? 0 : servers.size();
if (numServers == 0) {
LOG.warn("Wanted to do retain assignment but no servers to assign to");
return Collections.emptyMap();
return Collections.singletonMap(BOGUS_SERVER_NAME, new ArrayList<>(regions.keySet()));
}
if (numServers == 1) { // Only one server, nothing fancy we can do here

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@ -0,0 +1,162 @@
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package org.apache.hadoop.hbase.master.procedure;
import java.io.IOException;
import java.io.UncheckedIOException;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.hbase.HBaseClassTestRule;
import org.apache.hadoop.hbase.HBaseTestingUtil;
import org.apache.hadoop.hbase.StartTestingClusterOption;
import org.apache.hadoop.hbase.TableName;
import org.apache.hadoop.hbase.client.AsyncAdmin;
import org.apache.hadoop.hbase.client.ColumnFamilyDescriptorBuilder;
import org.apache.hadoop.hbase.client.Put;
import org.apache.hadoop.hbase.client.Table;
import org.apache.hadoop.hbase.client.TableDescriptor;
import org.apache.hadoop.hbase.client.TableDescriptorBuilder;
import org.apache.hadoop.hbase.master.HMaster;
import org.apache.hadoop.hbase.master.assignment.AssignmentManager;
import org.apache.hadoop.hbase.procedure2.Procedure;
import org.apache.hadoop.hbase.testclassification.MasterTests;
import org.apache.hadoop.hbase.testclassification.MediumTests;
import org.apache.hadoop.hbase.util.Bytes;
import org.apache.hadoop.metrics2.impl.JmxCacheBuster;
import org.junit.AfterClass;
import org.junit.BeforeClass;
import org.junit.ClassRule;
import org.junit.Test;
import org.junit.experimental.categories.Category;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.hadoop.hbase.shaded.protobuf.generated.MasterProcedureProtos.CreateTableState;
@Category({ MasterTests.class, MediumTests.class })
public class TestCreateTableNoRegionServer {
@ClassRule
public static final HBaseClassTestRule CLASS_RULE =
HBaseClassTestRule.forClass(TestCreateTableNoRegionServer.class);
private static final Logger LOG = LoggerFactory.getLogger(TestCreateTableNoRegionServer.class);
private static final HBaseTestingUtil UTIL = new HBaseTestingUtil();
private static CountDownLatch ARRIVE;
private static CountDownLatch RESUME;
public static final class HMasterForTest extends HMaster {
public HMasterForTest(Configuration conf) throws IOException {
super(conf);
}
private boolean isInAssignRegionsState() {
try {
for (StackTraceElement e : Thread.currentThread().getStackTrace()) {
if (e.getClassName().equals(CreateTableProcedure.class.getName()) &&
e.getMethodName().equals("executeFromState")) {
for (Procedure<?> proc : getProcedures()) {
if (proc instanceof CreateTableProcedure && ((CreateTableProcedure) proc)
.getCurrentStateId() == CreateTableState.CREATE_TABLE_ASSIGN_REGIONS_VALUE) {
return true;
}
}
}
}
} catch (IOException e) {
throw new UncheckedIOException(e);
}
return false;
}
@Override
public AssignmentManager getAssignmentManager() {
if (ARRIVE != null && isInAssignRegionsState()) {
ARRIVE.countDown();
ARRIVE = null;
try {
RESUME.await();
} catch (InterruptedException e) {
}
}
return super.getAssignmentManager();
}
}
@BeforeClass
public static void setUp() throws Exception {
UTIL.startMiniCluster(
StartTestingClusterOption.builder().masterClass(HMasterForTest.class).build());
// this may cause dead lock if there is no live region server and want to start a new server.
// In JmxCacheBuster we will reinitialize the metrics system so it will get some metrics which
// will need to access meta, since there is no region server, the request will hang there for a
// long time while holding the lock of MetricsSystemImpl, but when start a new region server, we
// also need to update metrics in handleReportForDutyResponse, since we are all in the same
// process and uses the same metrics instance, we hit dead lock.
JmxCacheBuster.stop();
}
@AfterClass
public static void tearDown() throws Exception {
UTIL.shutdownMiniCluster();
}
@Test
public void testCreate() throws Exception {
TableDescriptor td = TableDescriptorBuilder.newBuilder(TableName.valueOf("test"))
.setColumnFamily(ColumnFamilyDescriptorBuilder.of("f1")).build();
AsyncAdmin admin = UTIL.getAsyncConnection().getAdmin();
ARRIVE = new CountDownLatch(1);
RESUME = new CountDownLatch(1);
CompletableFuture<Void> future = admin.createTable(td);
ARRIVE.await();
UTIL.getMiniHBaseCluster().stopRegionServer(0).join();
// make sure we the region server is done.
UTIL.waitFor(30000,
() -> UTIL.getMiniHBaseCluster().getMaster().getServerManager().getOnlineServers().isEmpty());
RESUME.countDown();
Thread.sleep(10000);
// the procedure should still be in the CREATE_TABLE_ASSIGN_REGIONS state, but here, we just
// warn it as it may cause more serious problem later.
for (Procedure<?> proc : UTIL.getMiniHBaseCluster().getMaster().getProcedures()) {
if (proc instanceof CreateTableProcedure && !proc.isFinished() &&
((CreateTableProcedure) proc)
.getCurrentStateId() != CreateTableState.CREATE_TABLE_ASSIGN_REGIONS_VALUE) {
LOG.warn("Create table procedure {} assigned regions without a region server!", proc);
}
}
UTIL.getMiniHBaseCluster().startRegionServer();
// the creation should finally be done
future.get(30, TimeUnit.SECONDS);
// make sure we could put to the table
try (Table table = UTIL.getConnection().getTableBuilder(td.getTableName(), null)
.setOperationTimeout(5000).build()) {
table.put(new Put(Bytes.toBytes(0)).addColumn(td.getColumnFamilies()[0].getName(),
Bytes.toBytes("q"), Bytes.toBytes(0)));
}
}
}