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Revert "[SBN Read] Slow clients when Observer reads are enabled but there are no Observers on the cluster. Contributed by Chen Liang." 

This reverts commit ff8ff0f7e5.
This commit is contained in:
Chen Liang 2020-01-28 15:19:47 -08:00
parent ff8ff0f7e5
commit 3e86807802
4 changed files with 1 additions and 117 deletions
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50
hadoop-hdfs-project/hadoop-hdfs-client/src/main/java/org/apache/hadoop/hdfs/server/namenode/ha/ObserverReadProxyProvider.java
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@ -82,12 +82,6 @@ public class ObserverReadProxyProvider<T>
/** Client-side context for syncing with the NameNode server side. */
private final AlignmentContext alignmentContext;
/** Configuration key for {@link #observerProbeRetryPeriodMs}. */
static final String OBSERVER_PROBE_RETRY_PERIOD_KEY =
"dfs.client.failover.observer.probe.retry.period";
/** Observer probe retry period default to 10 min. */
static final long OBSERVER_PROBE_RETRY_PERIOD_DEFAULT = 60 * 10 * 1000;
/** The inner proxy provider used for active/standby failover. */
private final AbstractNNFailoverProxyProvider<T> failoverProxy;
/** List of all NameNode proxies. */
@ -146,21 +140,6 @@ public class ObserverReadProxyProvider<T>
/** The last proxy that has been used. Only used for testing. */
private volatile ProxyInfo<T> lastProxy = null;
/**
* In case there is no Observer node, for every read call, client will try
* to loop through all Standby nodes and fail eventually. Since there is no
* guarantee on when Observer node will be enabled. This can be very
* inefficient.
* The following value specify the period on how often to retry all Standby.
*/
private long observerProbeRetryPeriodMs;
/**
* The previous time where zero observer were found. If there was observer,
* or it is initialization, this is set to 0.
*/
private long lastObserverProbeTime;
/**
* By default ObserverReadProxyProvider uses
* {@link ConfiguredFailoverProxyProvider} for failover.
@ -179,7 +158,6 @@ public class ObserverReadProxyProvider<T>
this.failoverProxy = failoverProxy;
this.alignmentContext = new ClientGSIContext();
factory.setAlignmentContext(alignmentContext);
this.lastObserverProbeTime = 0;
// Don't bother configuring the number of retries and such on the retry
// policy since it is mainly only used for determining whether or not an
@ -210,9 +188,6 @@ public class ObserverReadProxyProvider<T>
// The host of the URI is the nameservice ID
AUTO_MSYNC_PERIOD_KEY_PREFIX + "." + uri.getHost(),
AUTO_MSYNC_PERIOD_DEFAULT, TimeUnit.MILLISECONDS);
observerProbeRetryPeriodMs = conf.getTimeDuration(
OBSERVER_PROBE_RETRY_PERIOD_KEY,
OBSERVER_PROBE_RETRY_PERIOD_DEFAULT, TimeUnit.MILLISECONDS);
// TODO : make this configurable or remove this variable
if (wrappedProxy instanceof ClientProtocol) {
@ -348,27 +323,6 @@ public class ObserverReadProxyProvider<T>
lastMsyncTimeMs = Time.monotonicNow();
}
/**
* Check if client need to find an Observer proxy.
* If current proxy is Active then we should stick to it and postpone probing
* for Observers for a period of time. When this time expires the client will
* try to find an Observer again.
* *
* @return true if we did not reach the threshold
* to start looking for Observer, or false otherwise.
*/
private boolean shouldFindObserver() {
// lastObserverProbeTime > 0 means we tried, but did not find any
// Observers yet
// If lastObserverProbeTime <= 0, previous check found observer, so
// we should not skip observer read.
if (lastObserverProbeTime > 0) {
return Time.monotonicNow() - lastObserverProbeTime
>= observerProbeRetryPeriodMs;
}
return true;
}
/**
* This will call {@link ClientProtocol#msync()} on the active NameNode
* (via the {@link #failoverProxy}) to update the state of this client, only
@ -416,7 +370,7 @@ public class ObserverReadProxyProvider<T>
lastProxy = null;
Object retVal;
if (observerReadEnabled && shouldFindObserver() && isRead(method)) {
if (observerReadEnabled && isRead(method)) {
if (!msynced) {
// An msync() must first be performed to ensure that this client is
// up-to-date with the active's state. This will only be done once.
@ -500,13 +454,11 @@ public class ObserverReadProxyProvider<T>
+ "also found {} standby, {} active, and {} unreachable. "
+ "Falling back to active.", failedObserverCount,
method.getName(), standbyCount, activeCount, unreachableCount);
lastObserverProbeTime = 0;
} else {
if (LOG.isDebugEnabled()) {
LOG.debug("Read falling back to active without observer read "
+ "fail, is there no observer node running?");
}
lastObserverProbeTime = Time.monotonicNow();
}
}

56
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestObserverNode.java
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@ -19,7 +19,6 @@ package org.apache.hadoop.hdfs.server.namenode.ha;
import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_STATE_CONTEXT_ENABLED_KEY;
import static org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter.getServiceState;
import static org.apache.hadoop.hdfs.server.namenode.ha.ObserverReadProxyProvider.*;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.junit.Assert.fail;
@ -34,9 +33,7 @@ import java.net.URI;
import java.util.ArrayList;
import java.util.List;
import java.util.concurrent.TimeUnit;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.FileUtil;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.permission.FsPermission;
@ -56,7 +53,6 @@ import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
import org.apache.hadoop.hdfs.server.namenode.TestFsck;
import org.apache.hadoop.hdfs.tools.GetGroups;
import org.apache.hadoop.ipc.ObserverRetryOnActiveException;
import org.apache.hadoop.util.Time;
import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
@ -84,10 +80,6 @@ public class TestObserverNode {
public static void startUpCluster() throws Exception {
conf = new Configuration();
conf.setBoolean(DFS_NAMENODE_STATE_CONTEXT_ENABLED_KEY, true);
// Set observer probe retry period to 0. Required by the tests that restart
// Observer and immediately try to read from it.
conf.setTimeDuration(
OBSERVER_PROBE_RETRY_PERIOD_KEY, 0, TimeUnit.MILLISECONDS);
qjmhaCluster = HATestUtil.setUpObserverCluster(conf, 1, 0, true);
dfsCluster = qjmhaCluster.getDfsCluster();
}
@ -421,54 +413,6 @@ public class TestObserverNode {
assertSentTo(0);
}
/**
* Test that if client connects to Active it does not try to find Observer
* on next calls during some period of time.
*/
@Test
public void testStickyActive() throws Exception {
Path testFile = new Path(testPath, "testStickyActive");
Configuration newConf = new Configuration(conf);
// Observer probe retry period set to 5 sec
newConf.setLong(OBSERVER_PROBE_RETRY_PERIOD_KEY, 5000);
// Disable cache, so that a new client actually gets created with new conf.
newConf.setBoolean("fs.hdfs.impl.disable.cache", true);
DistributedFileSystem newFs = (DistributedFileSystem) FileSystem.get(newConf);
newFs.create(testFile, (short)1).close();
assertSentTo(0);
dfsCluster.rollEditLogAndTail(0);
// No Observers present, should still go to Active
dfsCluster.transitionToStandby(2);
assertEquals("NN[2] should be standby", HAServiceState.STANDBY,
getServiceState(dfsCluster.getNameNode(2)));
newFs.open(testFile).close();
assertSentTo(0);
// Restore Observer
int newObserver = 1;
dfsCluster.transitionToObserver(newObserver);
assertEquals("NN[" + newObserver + "] should be observer",
HAServiceState.OBSERVER,
getServiceState(dfsCluster.getNameNode(newObserver)));
long startTime = Time.monotonicNow();
try {
while(Time.monotonicNow() - startTime <= 5000) {
newFs.open(testFile).close();
// Client should still talk to Active
assertSentTo(0);
Thread.sleep(200);
}
} catch(AssertionError ae) {
if(Time.monotonicNow() - startTime <= 5000) {
throw ae;
}
assertSentTo(newObserver);
} finally {
dfsCluster.transitionToStandby(1);
dfsCluster.transitionToObserver(2);
}
}
private void assertSentTo(int nnIdx) throws IOException {
assertTrue("Request was not sent to the expected namenode " + nnIdx,
HATestUtil.isSentToAnyOfNameNodes(dfs, dfsCluster, nnIdx));

6
hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/ha/TestObserverReadProxyProvider.java
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@ -24,7 +24,6 @@ import java.net.URI;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.atomic.AtomicBoolean;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.permission.FsAction;
@ -44,7 +43,6 @@ import org.mockito.stubbing.Answer;
import static org.apache.hadoop.ha.HAServiceProtocol.HAServiceState;
import static org.apache.hadoop.hdfs.server.namenode.ha.ObserverReadProxyProvider.*;
import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.fail;
@ -74,10 +72,6 @@ public class TestObserverReadProxyProvider {
nnURI = URI.create("hdfs://" + ns);
conf = new Configuration();
conf.set(HdfsClientConfigKeys.DFS_NAMESERVICES, ns);
// Set observer probe retry period to 0. Required by the tests that
// transition observer back and forth
conf.setTimeDuration(
OBSERVER_PROBE_RETRY_PERIOD_KEY, 0, TimeUnit.MILLISECONDS);
}
private void setupProxyProvider(int namenodeCount) throws Exception {

6
phantomjsdriver.log
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@ -1,6 +0,0 @@
[INFO - 2020-01-28T23:13:43.723Z] GhostDriver - Main - running on port 35401
[INFO - 2020-01-28T23:13:44.162Z] Session [d450b8d0-4223-11ea-891f-8fa5006f053d] - page.settings - {"XSSAuditingEnabled":false,"javascriptCanCloseWindows":true,"javascriptCanOpenWindows":true,"javascriptEnabled":true,"loadImages":true,"localToRemoteUrlAccessEnabled":false,"userAgent":"Mozilla/5.0 (Macintosh; Intel Mac OS X) AppleWebKit/538.1 (KHTML, like Gecko) PhantomJS/2.1.1 Safari/538.1","webSecurityEnabled":true}
[INFO - 2020-01-28T23:13:44.162Z] Session [d450b8d0-4223-11ea-891f-8fa5006f053d] - page.customHeaders: - {}
[INFO - 2020-01-28T23:13:44.162Z] Session [d450b8d0-4223-11ea-891f-8fa5006f053d] - Session.negotiatedCapabilities - {"browserName":"phantomjs","version":"2.1.1","driverName":"ghostdriver","driverVersion":"1.2.0","platform":"mac-unknown-64bit","javascriptEnabled":true,"takesScreenshot":true,"handlesAlerts":false,"databaseEnabled":false,"locationContextEnabled":false,"applicationCacheEnabled":false,"browserConnectionEnabled":false,"cssSelectorsEnabled":true,"webStorageEnabled":false,"rotatable":false,"acceptSslCerts":false,"nativeEvents":true,"proxy":{"proxyType":"direct"}}
[INFO - 2020-01-28T23:13:44.162Z] SessionManagerReqHand - _postNewSessionCommand - New Session Created: d450b8d0-4223-11ea-891f-8fa5006f053d
[INFO - 2020-01-28T23:13:44.990Z] ShutdownReqHand - _handle - About to shutdown