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HDFS-14230. RBF: Throw RetriableException instead of IOException when no namenodes available. Contributed by Fei Hui.

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This commit is contained in:
Inigo Goiri 2019-02-12 10:44:02 -08:00 committed by Brahma Reddy Battula
parent 912b90f91e
commit 7e63e37dc5
9 changed files with 188 additions and 10 deletions
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2
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationRPCMBean.java
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@ -46,6 +46,8 @@ public interface FederationRPCMBean {
long getProxyOpRetries();
long getProxyOpNoNamenodes();
long getRouterFailureStateStoreOps();
long getRouterFailureReadOnlyOps();

11
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationRPCMetrics.java
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@ -60,6 +60,8 @@ public class FederationRPCMetrics implements FederationRPCMBean {
private MutableCounterLong proxyOpNotImplemented;
@Metric("Number of operation retries")
private MutableCounterLong proxyOpRetries;
@Metric("Number of operations to hit no namenodes available")
private MutableCounterLong proxyOpNoNamenodes;
@Metric("Failed requests due to State Store unavailable")
private MutableCounterLong routerFailureStateStore;
@ -138,6 +140,15 @@ public long getProxyOpRetries() {
return proxyOpRetries.value();
}
public void incrProxyOpNoNamenodes() {
proxyOpNoNamenodes.incr();
}
@Override
public long getProxyOpNoNamenodes() {
return proxyOpNoNamenodes.value();
}
public void incrRouterFailureStateStore() {
routerFailureStateStore.incr();
}

5
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/metrics/FederationRPCPerformanceMonitor.java
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@ -170,6 +170,11 @@ public void proxyOpRetries() {
metrics.incrProxyOpRetries();
}
@Override
public void proxyOpNoNamenodes() {
metrics.incrProxyOpNoNamenodes();
}
@Override
public void routerFailureStateStore() {
metrics.incrRouterFailureStateStore();

33
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/NoNamenodesAvailableException.java Normal file
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@ -0,0 +1,33 @@
/**
* 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.hdfs.server.federation.router;
import java.io.IOException;
/**
* Exception when no namenodes are available.
*/
public class NoNamenodesAvailableException extends IOException {
private static final long serialVersionUID = 1L;
public NoNamenodesAvailableException(String nsId, IOException ioe) {
super("No namenodes available under nameservice " + nsId, ioe);
}
}

16
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcClient.java
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@ -61,6 +61,7 @@
import org.apache.hadoop.io.retry.RetryPolicy;
import org.apache.hadoop.io.retry.RetryPolicy.RetryAction.RetryDecision;
import org.apache.hadoop.ipc.RemoteException;
import org.apache.hadoop.ipc.RetriableException;
import org.apache.hadoop.ipc.StandbyException;
import org.apache.hadoop.security.UserGroupInformation;
import org.slf4j.Logger;
@ -302,8 +303,8 @@ private static IOException toIOException(Exception e) {
* @param retryCount Number of retries.
* @param nsId Nameservice ID.
* @return Retry decision.
* @throws IOException Original exception if the retry policy generates one
* or IOException for no available namenodes.
* @throws NoNamenodesAvailableException Exception that the retry policy
* generates for no available namenodes.
*/
private RetryDecision shouldRetry(final IOException ioe, final int retryCount,
final String nsId) throws IOException {
@ -313,8 +314,7 @@ private RetryDecision shouldRetry(final IOException ioe, final int retryCount,
if (retryCount == 0) {
return RetryDecision.RETRY;
} else {
throw new IOException("No namenode available under nameservice " + nsId,
ioe);
throw new NoNamenodesAvailableException(nsId, ioe);
}
}
@ -405,6 +405,14 @@ private Object invokeMethod(
StandbyException se = new StandbyException(ioe.getMessage());
se.initCause(ioe);
throw se;
} else if (ioe instanceof NoNamenodesAvailableException) {
if (this.rpcMonitor != null) {
this.rpcMonitor.proxyOpNoNamenodes();
}
LOG.error("Can not get available namenode for {} {} error: {}",
nsId, rpcAddress, ioe.getMessage());
// Throw RetriableException so that client can retry
throw new RetriableException(ioe);
} else {
// Other communication error, this is a failure
// Communication retries are handled by the retry policy

5
hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcMonitor.java
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@ -92,6 +92,11 @@ void init(
*/
void proxyOpRetries();
/**
* Failed to proxy an operation because of no namenodes available.
*/
void proxyOpNoNamenodes();
/**
* If the Router cannot contact the State Store in an operation.
*/

38
hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/FederationTestUtils.java
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@ -48,6 +48,7 @@
import org.apache.hadoop.fs.permission.FsPermission;
import org.apache.hadoop.ha.HAServiceProtocol.HAServiceState;
import org.apache.hadoop.hdfs.DFSConfigKeys;
import org.apache.hadoop.hdfs.server.federation.MiniRouterDFSCluster.NamenodeContext;
import org.apache.hadoop.hdfs.server.federation.resolver.ActiveNamenodeResolver;
import org.apache.hadoop.hdfs.server.federation.resolver.FederationNamenodeContext;
import org.apache.hadoop.hdfs.server.federation.resolver.FederationNamenodeServiceState;
@ -374,4 +375,41 @@ public Object answer(InvocationOnMock invocation) throws Throwable {
Whitebox.setInternalState(rpcClient, "connectionManager",
spyConnectionManager);
}
/**
* Switch namenodes of all hdfs name services to standby.
* @param cluster a federated HDFS cluster
*/
public static void transitionClusterNSToStandby(
StateStoreDFSCluster cluster) {
// Name services of the cluster
List<String> nameServiceList = cluster.getNameservices();
// Change namenodes of each name service to standby
for (String nameService : nameServiceList) {
List<NamenodeContext> nnList = cluster.getNamenodes(nameService);
for(NamenodeContext namenodeContext : nnList) {
cluster.switchToStandby(nameService, namenodeContext.getNamenodeId());
}
}
}
/**
* Switch the index namenode of all hdfs name services to active.
* @param cluster a federated HDFS cluster
* @param index the index of namenodes
*/
public static void transitionClusterNSToActive(
StateStoreDFSCluster cluster, int index) {
// Name services of the cluster
List<String> nameServiceList = cluster.getNameservices();
// Change the index namenode of each name service to active
for (String nameService : nameServiceList) {
List<NamenodeContext> listNamenodeContext =
cluster.getNamenodes(nameService);
cluster.switchToActive(nameService,
listNamenodeContext.get(index).getNamenodeId());
}
}
}

86
hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterClientRejectOverload.java
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@ -19,6 +19,8 @@
import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.simulateSlowNamenode;
import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.simulateThrowExceptionRouterRpcServer;
import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.transitionClusterNSToStandby;
import static org.apache.hadoop.hdfs.server.federation.FederationTestUtils.transitionClusterNSToActive;
import static org.apache.hadoop.test.GenericTestUtils.assertExceptionContains;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
@ -27,6 +29,7 @@
import java.io.IOException;
import java.net.URI;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
@ -46,7 +49,9 @@
import org.apache.hadoop.ipc.RemoteException;
import org.apache.hadoop.ipc.StandbyException;
import org.junit.After;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ExpectedException;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
@ -71,14 +76,19 @@ public void cleanup() {
}
}
private void setupCluster(boolean overloadControl) throws Exception {
@Rule
public ExpectedException exceptionRule = ExpectedException.none();
private void setupCluster(boolean overloadControl, boolean ha)
throws Exception {
// Build and start a federated cluster
cluster = new StateStoreDFSCluster(false, 2);
cluster = new StateStoreDFSCluster(ha, 2);
Configuration routerConf = new RouterConfigBuilder()
.stateStore()
.metrics()
.admin()
.rpc()
.heartbeat()
.build();
// Reduce the number of RPC clients threads to overload the Router easy
@ -98,7 +108,7 @@ private void setupCluster(boolean overloadControl) throws Exception {
@Test
public void testWithoutOverloadControl() throws Exception {
setupCluster(false);
setupCluster(false, false);
// Nobody should get overloaded
testOverloaded(0);
@ -121,7 +131,7 @@ public void testWithoutOverloadControl() throws Exception {
@Test
public void testOverloadControl() throws Exception {
setupCluster(true);
setupCluster(true, false);
List<RouterContext> routers = cluster.getRouters();
FederationRPCMetrics rpcMetrics0 =
@ -244,7 +254,7 @@ public void run() {
@Test
public void testConnectionNullException() throws Exception {
setupCluster(false);
setupCluster(false, false);
// Choose 1st router
RouterContext routerContext = cluster.getRouters().get(0);
@ -280,4 +290,70 @@ public void testConnectionNullException() throws Exception {
assertEquals(originalRouter1Failures,
rpcMetrics1.getProxyOpFailureCommunicate());
}
/**
* When failover occurs, no namenodes are available within a short time.
* Client will success after some retries.
*/
@Test
public void testNoNamenodesAvailable() throws Exception{
setupCluster(false, true);
transitionClusterNSToStandby(cluster);
Configuration conf = cluster.getRouterClientConf();
// Set dfs.client.failover.random.order false, to pick 1st router at first
conf.setBoolean("dfs.client.failover.random.order", false);
// Retries is 3 (see FailoverOnNetworkExceptionRetry#shouldRetry, will fail
// when reties > max.attempts), so total access is 4.
conf.setInt("dfs.client.retry.max.attempts", 2);
DFSClient routerClient = new DFSClient(new URI("hdfs://fed"), conf);
// Get router0 metrics
FederationRPCMetrics rpcMetrics0 = cluster.getRouters().get(0)
.getRouter().getRpcServer().getRPCMetrics();
// Get router1 metrics
FederationRPCMetrics rpcMetrics1 = cluster.getRouters().get(1)
.getRouter().getRpcServer().getRPCMetrics();
// Original failures
long originalRouter0Failures = rpcMetrics0.getProxyOpNoNamenodes();
long originalRouter1Failures = rpcMetrics1.getProxyOpNoNamenodes();
// GetFileInfo will throw Exception
String exceptionMessage = "org.apache.hadoop.hdfs.server.federation."
+ "router.NoNamenodesAvailableException: No namenodes available "
+ "under nameservice ns0";
exceptionRule.expect(RemoteException.class);
exceptionRule.expectMessage(exceptionMessage);
routerClient.getFileInfo("/");
// Router 0 failures will increase
assertEquals(originalRouter0Failures + 4,
rpcMetrics0.getProxyOpNoNamenodes());
// Router 1 failures do not change
assertEquals(originalRouter1Failures,
rpcMetrics1.getProxyOpNoNamenodes());
// Make name services available
transitionClusterNSToActive(cluster, 0);
for (RouterContext routerContext : cluster.getRouters()) {
// Manually trigger the heartbeat
Collection<NamenodeHeartbeatService> heartbeatServices = routerContext
.getRouter().getNamenodeHearbeatServices();
for (NamenodeHeartbeatService service : heartbeatServices) {
service.periodicInvoke();
}
// Update service cache
routerContext.getRouter().getStateStore().refreshCaches(true);
}
originalRouter0Failures = rpcMetrics0.getProxyOpNoNamenodes();
// RPC call must be successful
routerClient.getFileInfo("/");
// Router 0 failures do not change
assertEquals(originalRouter0Failures, rpcMetrics0.getProxyOpNoNamenodes());
}
}

2
hadoop-hdfs-project/hadoop-hdfs-rbf/src/test/java/org/apache/hadoop/hdfs/server/federation/router/TestRouterRPCClientRetries.java
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@ -133,7 +133,7 @@ public void testRetryWhenAllNameServiceDown() throws Exception {
} catch (RemoteException e) {
String ns0 = cluster.getNameservices().get(0);
assertExceptionContains(
"No namenode available under nameservice " + ns0, e);
"No namenodes available under nameservice " + ns0, e);
}
// Verify the retry times, it should only retry one time.