YARN-2180. [YARN-1492] In-memory backing store for cache manager. (Chris Trezzo via kasha)

This commit is contained in:
Karthik Kambatla 2014-10-09 17:16:06 -07:00
parent d8d628d1e0
commit 4f426fe223
11 changed files with 1275 additions and 2 deletions

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@ -36,6 +36,9 @@ Release 2.7.0 - UNRELEASED
YARN-2179. [YARN-1492] Initial cache manager structure and context. YARN-2179. [YARN-1492] Initial cache manager structure and context.
(Chris Trezzo via kasha) (Chris Trezzo via kasha)
YARN-2180. [YARN-1492] In-memory backing store for cache manager.
(Chris Trezzo via kasha)
IMPROVEMENTS IMPROVEMENTS
YARN-1979. TestDirectoryCollection fails when the umask is unusual. YARN-1979. TestDirectoryCollection fails when the umask is unusual.

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@ -1332,6 +1332,49 @@ public class YarnConfiguration extends Configuration {
SHARED_CACHE_PREFIX + "nested-level"; SHARED_CACHE_PREFIX + "nested-level";
public static final int DEFAULT_SHARED_CACHE_NESTED_LEVEL = 3; public static final int DEFAULT_SHARED_CACHE_NESTED_LEVEL = 3;
// Shared Cache Manager Configs
public static final String SCM_STORE_PREFIX = SHARED_CACHE_PREFIX + "store.";
public static final String SCM_STORE_CLASS = SCM_STORE_PREFIX + "class";
public static final String DEFAULT_SCM_STORE_CLASS =
"org.apache.hadoop.yarn.server.sharedcachemanager.store.InMemorySCMStore";
public static final String SCM_APP_CHECKER_CLASS = SHARED_CACHE_PREFIX
+ "app-checker.class";
public static final String DEFAULT_SCM_APP_CHECKER_CLASS =
"org.apache.hadoop.yarn.server.sharedcachemanager.RemoteAppChecker";
// In-memory SCM store configuration
public static final String IN_MEMORY_STORE_PREFIX =
SHARED_CACHE_PREFIX + "in-memory.";
/**
* A resource in the InMemorySCMStore is considered stale if the time since
* the last reference exceeds the staleness period. This value is specified in
* minutes.
*/
public static final String IN_MEMORY_STALENESS_PERIOD =
IN_MEMORY_STORE_PREFIX + "staleness-period";
public static final int DEFAULT_IN_MEMORY_STALENESS_PERIOD = 7 * 24 * 60;
/**
* Initial delay before the in-memory store runs its first check to remove
* dead initial applications. Specified in minutes.
*/
public static final String IN_MEMORY_INITIAL_DELAY =
IN_MEMORY_STORE_PREFIX + "initial-delay";
public static final int DEFAULT_IN_MEMORY_INITIAL_DELAY = 10;
/**
* The frequency at which the in-memory store checks to remove dead initial
* applications. Specified in minutes.
*/
public static final String IN_MEMORY_CHECK_PERIOD =
IN_MEMORY_STORE_PREFIX + "check-period";
public static final int DEFAULT_IN_MEMORY_CHECK_PERIOD = 12 * 60;
//////////////////////////////// ////////////////////////////////
// Other Configs // Other Configs
//////////////////////////////// ////////////////////////////////

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@ -1342,6 +1342,40 @@
<value>3</value> <value>3</value>
</property> </property>
<property>
<description>The implementation to be used for the SCM store</description>
<name>yarn.sharedcache.store.class</name>
<value>org.apache.hadoop.yarn.server.sharedcachemanager.store.InMemorySCMStore</value>
</property>
<property>
<description>The implementation to be used for the SCM app-checker</description>
<name>yarn.sharedcache.app-checker.class</name>
<value>org.apache.hadoop.yarn.server.sharedcachemanager.RemoteAppChecker</value>
</property>
<property>
<description>A resource in the in-memory store is considered stale
if the time since the last reference exceeds the staleness period.
This value is specified in minutes.</description>
<name>yarn.sharedcache.store.in-memory.staleness-period</name>
<value>10080</value>
</property>
<property>
<description>Initial delay before the in-memory store runs its first check
to remove dead initial applications. Specified in minutes.</description>
<name>yarn.sharedcache.store.in-memory.initial-delay</name>
<value>10</value>
</property>
<property>
<description>The frequency at which the in-memory store checks to remove
dead initial applications. Specified in minutes.</description>
<name>yarn.sharedcache.store.in-memory.check-period</name>
<value>720</value>
</property>
<!-- Other configuration --> <!-- Other configuration -->
<property> <property>
<description>The interval that the yarn client library uses to poll the <description>The interval that the yarn client library uses to poll the

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@ -32,9 +32,9 @@ import org.apache.hadoop.yarn.conf.YarnConfiguration;
*/ */
@Private @Private
@Unstable @Unstable
public class SharedCacheStructureUtil { public class SharedCacheUtil {
private static final Log LOG = LogFactory.getLog(SharedCacheStructureUtil.class); private static final Log LOG = LogFactory.getLog(SharedCacheUtil.class);
@Private @Private
public static int getCacheDepth(Configuration conf) { public static int getCacheDepth(Configuration conf) {

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@ -42,6 +42,10 @@
<groupId>org.apache.hadoop</groupId> <groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-yarn-common</artifactId> <artifactId>hadoop-yarn-common</artifactId>
</dependency> </dependency>
<dependency>
<groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-yarn-server-common</artifactId>
</dependency>
<dependency> <dependency>
<groupId>org.apache.hadoop</groupId> <groupId>org.apache.hadoop</groupId>
<artifactId>hadoop-yarn-client</artifactId> <artifactId>hadoop-yarn-client</artifactId>

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@ -26,10 +26,15 @@ import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem; import org.apache.hadoop.metrics2.lib.DefaultMetricsSystem;
import org.apache.hadoop.metrics2.source.JvmMetrics; import org.apache.hadoop.metrics2.source.JvmMetrics;
import org.apache.hadoop.service.CompositeService; import org.apache.hadoop.service.CompositeService;
import org.apache.hadoop.util.ReflectionUtils;
import org.apache.hadoop.util.ShutdownHookManager; import org.apache.hadoop.util.ShutdownHookManager;
import org.apache.hadoop.util.StringUtils; import org.apache.hadoop.util.StringUtils;
import org.apache.hadoop.yarn.YarnUncaughtExceptionHandler; import org.apache.hadoop.yarn.YarnUncaughtExceptionHandler;
import org.apache.hadoop.yarn.conf.YarnConfiguration; import org.apache.hadoop.yarn.conf.YarnConfiguration;
import org.apache.hadoop.yarn.exceptions.YarnRuntimeException;
import org.apache.hadoop.yarn.server.sharedcachemanager.store.SCMStore;
import com.google.common.annotations.VisibleForTesting;
/** /**
* This service maintains the shared cache meta data. It handles claiming and * This service maintains the shared cache meta data. It handles claiming and
@ -47,12 +52,18 @@ public class SharedCacheManager extends CompositeService {
private static final Log LOG = LogFactory.getLog(SharedCacheManager.class); private static final Log LOG = LogFactory.getLog(SharedCacheManager.class);
private SCMStore store;
public SharedCacheManager() { public SharedCacheManager() {
super("SharedCacheManager"); super("SharedCacheManager");
} }
@Override @Override
protected void serviceInit(Configuration conf) throws Exception { protected void serviceInit(Configuration conf) throws Exception {
this.store = createSCMStoreService(conf);
addService(store);
// init metrics // init metrics
DefaultMetricsSystem.initialize("SharedCacheManager"); DefaultMetricsSystem.initialize("SharedCacheManager");
JvmMetrics.initSingleton("SharedCacheManager", null); JvmMetrics.initSingleton("SharedCacheManager", null);
@ -60,6 +71,25 @@ public class SharedCacheManager extends CompositeService {
super.serviceInit(conf); super.serviceInit(conf);
} }
@SuppressWarnings("unchecked")
private static SCMStore createSCMStoreService(Configuration conf) {
Class<? extends SCMStore> defaultStoreClass;
try {
defaultStoreClass =
(Class<? extends SCMStore>) Class
.forName(YarnConfiguration.DEFAULT_SCM_STORE_CLASS);
} catch (Exception e) {
throw new YarnRuntimeException("Invalid default scm store class"
+ YarnConfiguration.DEFAULT_SCM_STORE_CLASS, e);
}
SCMStore store =
ReflectionUtils.newInstance(conf.getClass(
YarnConfiguration.SCM_STORE_CLASS,
defaultStoreClass, SCMStore.class), conf);
return store;
}
@Override @Override
protected void serviceStop() throws Exception { protected void serviceStop() throws Exception {
@ -67,6 +97,14 @@ public class SharedCacheManager extends CompositeService {
super.serviceStop(); super.serviceStop();
} }
/**
* For testing purposes only.
*/
@VisibleForTesting
SCMStore getSCMStore() {
return this.store;
}
public static void main(String[] args) { public static void main(String[] args) {
Thread.setDefaultUncaughtExceptionHandler(new YarnUncaughtExceptionHandler()); Thread.setDefaultUncaughtExceptionHandler(new YarnUncaughtExceptionHandler());
StringUtils.startupShutdownMessage(SharedCacheManager.class, args, LOG); StringUtils.startupShutdownMessage(SharedCacheManager.class, args, LOG);
@ -83,4 +121,24 @@ public class SharedCacheManager extends CompositeService {
System.exit(-1); System.exit(-1);
} }
} }
@Private
@SuppressWarnings("unchecked")
public static AppChecker createAppCheckerService(Configuration conf) {
Class<? extends AppChecker> defaultCheckerClass;
try {
defaultCheckerClass =
(Class<? extends AppChecker>) Class
.forName(YarnConfiguration.DEFAULT_SCM_APP_CHECKER_CLASS);
} catch (Exception e) {
throw new YarnRuntimeException("Invalid default scm app checker class"
+ YarnConfiguration.DEFAULT_SCM_APP_CHECKER_CLASS, e);
}
AppChecker checker =
ReflectionUtils.newInstance(conf.getClass(
YarnConfiguration.SCM_APP_CHECKER_CLASS, defaultCheckerClass,
AppChecker.class), conf);
return checker;
}
} }

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@ -0,0 +1,514 @@
/**
* 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.yarn.server.sharedcachemanager.store;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.TimeUnit;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.HadoopIllegalArgumentException;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.util.StringInterner;
import org.apache.hadoop.yarn.api.records.ApplicationId;
import org.apache.hadoop.yarn.conf.YarnConfiguration;
import org.apache.hadoop.yarn.exceptions.YarnException;
import org.apache.hadoop.yarn.server.sharedcache.SharedCacheUtil;
import org.apache.hadoop.yarn.server.sharedcachemanager.AppChecker;
import org.apache.hadoop.yarn.server.sharedcachemanager.SharedCacheManager;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.util.concurrent.ThreadFactoryBuilder;
/**
* A thread safe version of an in-memory SCM store. The thread safety is
* implemented with two key pieces: (1) at the mapping level a ConcurrentHashMap
* is used to allow concurrency to resources and their associated references,
* and (2) a key level lock is used to ensure mutual exclusion between any
* operation that accesses a resource with the same key. <br>
* <br>
* To ensure safe key-level locking, we use the original string key and intern
* it weakly using hadoop's <code>StringInterner</code>. It avoids the pitfalls
* of using built-in String interning. The interned strings are also weakly
* referenced, so it can be garbage collected once it is done. And there is
* little risk of keys being available for other parts of the code so they can
* be used as locks accidentally. <br>
* <br>
* Resources in the in-memory store are evicted based on a time staleness
* criteria. If a resource is not referenced (i.e. used) for a given period, it
* is designated as a stale resource and is considered evictable.
*/
@Private
@Evolving
public class InMemorySCMStore extends SCMStore {
private static final Log LOG = LogFactory.getLog(InMemorySCMStore.class);
private final Map<String, SharedCacheResource> cachedResources =
new ConcurrentHashMap<String, SharedCacheResource>();
private Collection<ApplicationId> initialApps =
new ArrayList<ApplicationId>();
private final Object initialAppsLock = new Object();
private long startTime;
private int stalenessMinutes;
private AppChecker appChecker;
private ScheduledExecutorService scheduler;
private int initialDelayMin;
private int checkPeriodMin;
public InMemorySCMStore() {
super(InMemorySCMStore.class.getName());
}
private String intern(String key) {
return StringInterner.weakIntern(key);
}
/**
* The in-memory store bootstraps itself from the shared cache entries that
* exist in HDFS.
*/
@Override
protected void serviceInit(Configuration conf) throws Exception {
this.startTime = System.currentTimeMillis();
this.initialDelayMin = getInitialDelay(conf);
this.checkPeriodMin = getCheckPeriod(conf);
this.stalenessMinutes = getStalenessPeriod(conf);
appChecker = createAppCheckerService(conf);
addService(appChecker);
bootstrap(conf);
ThreadFactory tf =
new ThreadFactoryBuilder().setNameFormat("InMemorySCMStore")
.build();
scheduler = Executors.newSingleThreadScheduledExecutor(tf);
super.serviceInit(conf);
}
@Override
protected void serviceStart() throws Exception {
// start composed services first
super.serviceStart();
// Get initial list of running applications
LOG.info("Getting the active app list to initialize the in-memory scm store");
synchronized (initialAppsLock) {
initialApps = appChecker.getActiveApplications();
}
LOG.info(initialApps.size() + " apps recorded as active at this time");
Runnable task = new AppCheckTask(appChecker);
scheduler.scheduleAtFixedRate(task, initialDelayMin, checkPeriodMin,
TimeUnit.MINUTES);
LOG.info("Scheduled the in-memory scm store app check task to run every "
+ checkPeriodMin + " minutes.");
}
@Override
protected void serviceStop() throws Exception {
LOG.info("Shutting down the background thread.");
scheduler.shutdownNow();
try {
if (!scheduler.awaitTermination(10, TimeUnit.SECONDS)) {
LOG.warn("Gave up waiting for the app check task to shutdown.");
}
} catch (InterruptedException e) {
LOG.warn("The InMemorySCMStore was interrupted while shutting down the "
+ "app check task.", e);
}
LOG.info("The background thread stopped.");
super.serviceStop();
}
@VisibleForTesting
AppChecker createAppCheckerService(Configuration conf) {
return SharedCacheManager.createAppCheckerService(conf);
}
private void bootstrap(Configuration conf) throws IOException {
Map<String, String> initialCachedResources =
getInitialCachedResources(FileSystem.get(conf), conf);
LOG.info("Bootstrapping from " + initialCachedResources.size()
+ " cache resources located in the file system");
Iterator<Map.Entry<String, String>> it =
initialCachedResources.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> e = it.next();
String key = intern(e.getKey());
String fileName = e.getValue();
SharedCacheResource resource = new SharedCacheResource(fileName);
// we don't hold the lock for this as it is done as part of serviceInit
cachedResources.put(key, resource);
// clear out the initial resource to reduce the footprint
it.remove();
}
LOG.info("Bootstrapping complete");
}
@VisibleForTesting
Map<String, String> getInitialCachedResources(FileSystem fs,
Configuration conf) throws IOException {
// get the root directory for the shared cache
String location =
conf.get(YarnConfiguration.SHARED_CACHE_ROOT,
YarnConfiguration.DEFAULT_SHARED_CACHE_ROOT);
Path root = new Path(location);
if (!fs.exists(root)) {
String message =
"The shared cache root directory " + location + " was not found";
LOG.error(message);
throw new IOException(message);
}
int nestedLevel = SharedCacheUtil.getCacheDepth(conf);
// now traverse individual directories and process them
// the directory structure is specified by the nested level parameter
// (e.g. 9/c/d/<checksum>/file)
StringBuilder pattern = new StringBuilder();
for (int i = 0; i < nestedLevel + 1; i++) {
pattern.append("*/");
}
pattern.append("*");
LOG.info("Querying for all individual cached resource files");
FileStatus[] entries = fs.globStatus(new Path(root, pattern.toString()));
int numEntries = entries == null ? 0 : entries.length;
LOG.info("Found " + numEntries + " files: processing for one resource per "
+ "key");
Map<String, String> initialCachedEntries = new HashMap<String, String>();
if (entries != null) {
for (FileStatus entry : entries) {
Path file = entry.getPath();
String fileName = file.getName();
if (entry.isFile()) {
// get the parent to get the checksum
Path parent = file.getParent();
if (parent != null) {
// the name of the immediate parent directory is the checksum
String key = parent.getName();
// make sure we insert only one file per checksum whichever comes
// first
if (initialCachedEntries.containsKey(key)) {
LOG.warn("Key " + key + " is already mapped to file "
+ initialCachedEntries.get(key) + "; file " + fileName
+ " will not be added");
} else {
initialCachedEntries.put(key, fileName);
}
}
}
}
}
LOG.info("A total of " + initialCachedEntries.size()
+ " files are now mapped");
return initialCachedEntries;
}
/**
* Adds the given resource to the store under the key and the filename. If the
* entry is already found, it returns the existing filename. It represents the
* state of the store at the time of this query. The entry may change or even
* be removed once this method returns. The caller should be prepared to
* handle that situation.
*
* @return the filename of the newly inserted resource or that of the existing
* resource
*/
@Override
public String addResource(String key, String fileName) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
if (resource == null) {
resource = new SharedCacheResource(fileName);
cachedResources.put(interned, resource);
}
return resource.getFileName();
}
}
/**
* Adds the provided resource reference to the cache resource under the key,
* and updates the access time. If it returns a non-null value, the caller may
* safely assume that the resource will not be removed at least until the app
* in this resource reference has terminated.
*
* @return the filename of the resource, or null if the resource is not found
*/
@Override
public String addResourceReference(String key,
SharedCacheResourceReference ref) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
if (resource == null) { // it's not mapped
return null;
}
resource.addReference(ref);
resource.updateAccessTime();
return resource.getFileName();
}
}
/**
* Returns the list of resource references currently registered under the
* cache entry. If the list is empty, it returns an empty collection. The
* returned collection is unmodifiable and a snapshot of the information at
* the time of the query. The state may change after this query returns. The
* caller should handle the situation that some or all of these resource
* references are no longer relevant.
*
* @return the collection that contains the resource references associated
* with the resource; or an empty collection if no resource references
* are registered under this resource
*/
@Override
public Collection<SharedCacheResourceReference> getResourceReferences(String key) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
if (resource == null) {
return Collections.emptySet();
}
Set<SharedCacheResourceReference> refs =
new HashSet<SharedCacheResourceReference>(
resource.getResourceReferences());
return Collections.unmodifiableSet(refs);
}
}
/**
* Removes the provided resource reference from the resource. If the resource
* does not exist, nothing will be done.
*/
@Override
public boolean removeResourceReference(String key, SharedCacheResourceReference ref,
boolean updateAccessTime) {
String interned = intern(key);
synchronized (interned) {
boolean removed = false;
SharedCacheResource resource = cachedResources.get(interned);
if (resource != null) {
Set<SharedCacheResourceReference> resourceRefs =
resource.getResourceReferences();
removed = resourceRefs.remove(ref);
if (updateAccessTime) {
resource.updateAccessTime();
}
}
return removed;
}
}
/**
* Removes the provided collection of resource references from the resource.
* If the resource does not exist, nothing will be done.
*/
@Override
public void removeResourceReferences(String key,
Collection<SharedCacheResourceReference> refs, boolean updateAccessTime) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
if (resource != null) {
Set<SharedCacheResourceReference> resourceRefs =
resource.getResourceReferences();
resourceRefs.removeAll(refs);
if (updateAccessTime) {
resource.updateAccessTime();
}
}
}
}
/**
* Removes the given resource from the store. Returns true if the resource is
* found and removed or if the resource is not found. Returns false if it was
* unable to remove the resource because the resource reference list was not
* empty.
*/
@Override
public boolean removeResource(String key) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
if (resource == null) {
return true;
}
if (!resource.getResourceReferences().isEmpty()) {
return false;
}
// no users
cachedResources.remove(interned);
return true;
}
}
/**
* Obtains the access time for a resource. It represents the view of the
* resource at the time of the query. The value may have been updated at a
* later point.
*
* @return the access time of the resource if found; -1 if the resource is not
* found
*/
@VisibleForTesting
long getAccessTime(String key) {
String interned = intern(key);
synchronized (interned) {
SharedCacheResource resource = cachedResources.get(interned);
return resource == null ? -1 : resource.getAccessTime();
}
}
@Override
public boolean isResourceEvictable(String key, FileStatus file) {
synchronized (initialAppsLock) {
if (initialApps.size() > 0) {
return false;
}
}
long staleTime =
System.currentTimeMillis()
- TimeUnit.MINUTES.toMillis(this.stalenessMinutes);
long accessTime = getAccessTime(key);
if (accessTime == -1) {
// check modification time
long modTime = file.getModificationTime();
// if modification time is older then the store startup time, we need to
// just use the store startup time as the last point of certainty
long lastUse = modTime < this.startTime ? this.startTime : modTime;
return lastUse < staleTime;
} else {
// check access time
return accessTime < staleTime;
}
}
private static int getStalenessPeriod(Configuration conf) {
int stalenessMinutes =
conf.getInt(YarnConfiguration.IN_MEMORY_STALENESS_PERIOD,
YarnConfiguration.DEFAULT_IN_MEMORY_STALENESS_PERIOD);
// non-positive value is invalid; use the default
if (stalenessMinutes <= 0) {
throw new HadoopIllegalArgumentException("Non-positive staleness value: "
+ stalenessMinutes
+ ". The staleness value must be greater than zero.");
}
return stalenessMinutes;
}
private static int getInitialDelay(Configuration conf) {
int initialMinutes =
conf.getInt(YarnConfiguration.IN_MEMORY_INITIAL_DELAY,
YarnConfiguration.DEFAULT_IN_MEMORY_INITIAL_DELAY);
// non-positive value is invalid; use the default
if (initialMinutes <= 0) {
throw new HadoopIllegalArgumentException(
"Non-positive initial delay value: " + initialMinutes
+ ". The initial delay value must be greater than zero.");
}
return initialMinutes;
}
private static int getCheckPeriod(Configuration conf) {
int checkMinutes =
conf.getInt(YarnConfiguration.IN_MEMORY_CHECK_PERIOD,
YarnConfiguration.DEFAULT_IN_MEMORY_CHECK_PERIOD);
// non-positive value is invalid; use the default
if (checkMinutes <= 0) {
throw new HadoopIllegalArgumentException(
"Non-positive check period value: " + checkMinutes
+ ". The check period value must be greater than zero.");
}
return checkMinutes;
}
@Private
@Evolving
class AppCheckTask implements Runnable {
private final AppChecker taskAppChecker;
public AppCheckTask(AppChecker appChecker) {
this.taskAppChecker = appChecker;
}
@Override
public void run() {
try {
LOG.info("Checking the initial app list for finished applications.");
synchronized (initialAppsLock) {
if (initialApps.isEmpty()) {
// we're fine, no-op; there are no active apps that were running at
// the time of the service start
} else {
LOG.info("Looking into " + initialApps.size()
+ " apps to see if they are still active");
Iterator<ApplicationId> it = initialApps.iterator();
while (it.hasNext()) {
ApplicationId id = it.next();
try {
if (!taskAppChecker.isApplicationActive(id)) {
// remove it from the list
it.remove();
}
} catch (YarnException e) {
LOG.warn("Exception while checking the app status;"
+ " will leave the entry in the list", e);
// continue
}
}
}
LOG.info("There are now " + initialApps.size()
+ " entries in the list");
}
} catch (Throwable e) {
LOG.error(
"Unexpected exception thrown during in-memory store app check task."
+ " Rescheduling task.", e);
}
}
}
}

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@ -0,0 +1,133 @@
/**
* 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.yarn.server.sharedcachemanager.store;
import java.util.Collection;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.service.CompositeService;
/**
* An abstract class for the data store used by the shared cache manager
* service. All implementations of methods in this interface need to be thread
* safe and atomic.
*/
@Private
@Evolving
public abstract class SCMStore extends CompositeService {
protected SCMStore(String name) {
super(name);
}
/**
* Add a resource to the shared cache and it's associated filename. The
* resource is identified by a unique key. If the key already exists no action
* is taken and the filename of the existing resource is returned. If the key
* does not exist, the resource is added, it's access time is set, and the
* filename of the resource is returned.
*
* @param key a unique identifier for a resource
* @param fileName the filename of the resource
* @return the filename of the resource as represented by the cache
*/
@Private
public abstract String addResource(String key, String fileName);
/**
* Remove a resource from the shared cache.
*
* @param key a unique identifier for a resource
* @return true if the resource was removed or did not exist, false if the
* resource existed, contained at least one
* <code>SharedCacheResourceReference</code> and was not removed.
*/
@Private
public abstract boolean removeResource(String key);
/**
* Add a <code>SharedCacheResourceReference</code> to a resource and update
* the resource access time.
*
* @param key a unique identifier for a resource
* @param ref the <code>SharedCacheResourceReference</code> to add
* @return String the filename of the resource if the
* <code>SharedCacheResourceReference</code> was added or already
* existed. null if the resource did not exist
*/
@Private
public abstract String addResourceReference(String key,
SharedCacheResourceReference ref);
/**
* Get the <code>SharedCacheResourceReference</code>(s) associated with the
* resource.
*
* @param key a unique identifier for a resource
* @return an unmodifiable collection of
* <code>SharedCacheResourceReferences</code>. If the resource does
* not exist, an empty set is returned.
*/
@Private
public abstract Collection<SharedCacheResourceReference> getResourceReferences(
String key);
/**
* Remove a <code>SharedCacheResourceReference</code> from a resource.
*
* @param key a unique identifier for a resource
* @param ref the <code>SharedCacheResourceReference</code> to remove
* @param updateAccessTime true if the call should update the access time for
* the resource
* @return true if the reference was removed, false otherwise
*/
@Private
public abstract boolean removeResourceReference(String key,
SharedCacheResourceReference ref, boolean updateAccessTime);
/**
* Remove a collection of <code>SharedCacheResourceReferences</code> from a
* resource.
*
* @param key a unique identifier for a resource
* @param refs the collection of <code>SharedCacheResourceReference</code>s to
* remove
* @param updateAccessTime true if the call should update the access time for
* the resource
*/
@Private
public abstract void removeResourceReferences(String key,
Collection<SharedCacheResourceReference> refs, boolean updateAccessTime);
/**
* Check if a specific resource is evictable according to the store's enabled
* cache eviction policies.
*
* @param key a unique identifier for a resource
* @param file the <code>FileStatus</code> object for the resource file in the
* file system.
* @return true if the resource is evicatble, false otherwise
*/
@Private
public abstract boolean isResourceEvictable(String key, FileStatus file);
}

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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.
*/
package org.apache.hadoop.yarn.server.sharedcachemanager.store;
import java.util.HashSet;
import java.util.Set;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
/**
* Class that encapsulates the cache resource. The instances are not thread
* safe. Any operation that uses the resource must use thread-safe mechanisms to
* ensure safe access with the only exception of the filename.
*/
@Private
@Evolving
class SharedCacheResource {
private long accessTime;
private final Set<SharedCacheResourceReference> refs;
private final String fileName;
SharedCacheResource(String fileName) {
this.accessTime = System.currentTimeMillis();
this.refs = new HashSet<SharedCacheResourceReference>();
this.fileName = fileName;
}
long getAccessTime() {
return accessTime;
}
void updateAccessTime() {
accessTime = System.currentTimeMillis();
}
String getFileName() {
return this.fileName;
}
Set<SharedCacheResourceReference> getResourceReferences() {
return this.refs;
}
boolean addReference(SharedCacheResourceReference ref) {
return this.refs.add(ref);
}
}

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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.
*/
package org.apache.hadoop.yarn.server.sharedcachemanager.store;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.classification.InterfaceStability.Evolving;
import org.apache.hadoop.yarn.api.records.ApplicationId;
/**
* This is an object that represents a reference to a shared cache resource.
*/
@Private
@Evolving
public class SharedCacheResourceReference {
private final ApplicationId appId;
private final String shortUserName;
/**
* Create a resource reference.
*
* @param appId <code>ApplicationId</code> that is referencing a resource.
* @param shortUserName <code>ShortUserName</code> of the user that created
* the reference.
*/
public SharedCacheResourceReference(ApplicationId appId, String shortUserName) {
this.appId = appId;
this.shortUserName = shortUserName;
}
public ApplicationId getAppId() {
return this.appId;
}
public String getShortUserName() {
return this.shortUserName;
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result + ((appId == null) ? 0 : appId.hashCode());
result =
prime * result
+ ((shortUserName == null) ? 0 : shortUserName.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
SharedCacheResourceReference other = (SharedCacheResourceReference) obj;
if (appId == null) {
if (other.appId != null)
return false;
} else if (!appId.equals(other.appId))
return false;
if (shortUserName == null) {
if (other.shortUserName != null)
return false;
} else if (!shortUserName.equals(other.shortUserName))
return false;
return true;
}
}

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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.
*/
package org.apache.hadoop.yarn.server.sharedcachemanager.store;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.mockito.Matchers.isA;
import static org.mockito.Mockito.doReturn;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.spy;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import org.apache.hadoop.classification.InterfaceAudience.Private;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileStatus;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.yarn.api.records.ApplicationId;
import org.apache.hadoop.yarn.exceptions.YarnException;
import org.apache.hadoop.yarn.server.sharedcachemanager.AppChecker;
import org.junit.After;
import org.junit.Before;
import org.junit.Test;
public class TestInMemorySCMStore {
private InMemorySCMStore store;
private AppChecker checker;
@Before
public void setup() {
this.store = spy(new InMemorySCMStore());
this.checker = spy(new DummyAppChecker());
doReturn(checker).when(store).createAppCheckerService(
isA(Configuration.class));
}
@After
public void cleanup() {
if (this.store != null) {
this.store.stop();
}
}
private void startEmptyStore() throws Exception {
doReturn(new ArrayList<ApplicationId>()).when(checker)
.getActiveApplications();
doReturn(new HashMap<String, String>()).when(store)
.getInitialCachedResources(isA(FileSystem.class),
isA(Configuration.class));
this.store.init(new Configuration());
this.store.start();
}
private Map<String, String> startStoreWithResources() throws Exception {
Map<String, String> initialCachedResources = new HashMap<String, String>();
int count = 10;
for (int i = 0; i < count; i++) {
String key = String.valueOf(i);
String fileName = key + ".jar";
initialCachedResources.put(key, fileName);
}
doReturn(new ArrayList<ApplicationId>()).when(checker)
.getActiveApplications();
doReturn(initialCachedResources).when(store).getInitialCachedResources(
isA(FileSystem.class), isA(Configuration.class));
this.store.init(new Configuration());
this.store.start();
return initialCachedResources;
}
private void startStoreWithApps() throws Exception {
ArrayList<ApplicationId> list = new ArrayList<ApplicationId>();
int count = 5;
for (int i = 0; i < count; i++) {
list.add(createAppId(i, i));
}
doReturn(list).when(checker).getActiveApplications();
doReturn(new HashMap<String, String>()).when(store)
.getInitialCachedResources(isA(FileSystem.class),
isA(Configuration.class));
this.store.init(new Configuration());
this.store.start();
}
@Test
public void testAddResourceConcurrency() throws Exception {
startEmptyStore();
final String key = "key1";
int count = 5;
ExecutorService exec = Executors.newFixedThreadPool(count);
List<Future<String>> futures = new ArrayList<Future<String>>(count);
final CountDownLatch start = new CountDownLatch(1);
for (int i = 0; i < count; i++) {
final String fileName = "foo-" + i + ".jar";
Callable<String> task = new Callable<String>() {
public String call() throws Exception {
start.await();
String result = store.addResource(key, fileName);
System.out.println("fileName: " + fileName + ", result: " + result);
return result;
}
};
futures.add(exec.submit(task));
}
// start them all at the same time
start.countDown();
// check the result; they should all agree with the value
Set<String> results = new HashSet<String>();
for (Future<String> future: futures) {
results.add(future.get());
}
assertSame(1, results.size());
exec.shutdown();
}
@Test
public void testAddResourceRefNonExistentResource() throws Exception {
startEmptyStore();
String key = "key1";
ApplicationId id = createAppId(1, 1L);
// try adding an app id without adding the key first
assertNull(store.addResourceReference(key,
new SharedCacheResourceReference(id, "user")));
}
@Test
public void testRemoveResourceEmptyRefs() throws Exception {
startEmptyStore();
String key = "key1";
String fileName = "foo.jar";
// first add resource
store.addResource(key, fileName);
// try removing the resource; it should return true
assertTrue(store.removeResource(key));
}
@Test
public void testAddResourceRefRemoveResource() throws Exception {
startEmptyStore();
String key = "key1";
ApplicationId id = createAppId(1, 1L);
String user = "user";
// add the resource, and then add a resource ref
store.addResource(key, "foo.jar");
store.addResourceReference(key, new SharedCacheResourceReference(id, user));
// removeResource should return false
assertTrue(!store.removeResource(key));
// the resource and the ref should be intact
Collection<SharedCacheResourceReference> refs = store.getResourceReferences(key);
assertTrue(refs != null);
assertEquals(Collections.singleton(new SharedCacheResourceReference(id, user)), refs);
}
@Test
public void testAddResourceRefConcurrency() throws Exception {
startEmptyStore();
final String key = "key1";
final String user = "user";
String fileName = "foo.jar";
// first add the resource
store.addResource(key, fileName);
// make concurrent addResourceRef calls (clients)
int count = 5;
ExecutorService exec = Executors.newFixedThreadPool(count);
List<Future<String>> futures = new ArrayList<Future<String>>(count);
final CountDownLatch start = new CountDownLatch(1);
for (int i = 0; i < count; i++) {
final ApplicationId id = createAppId(i, i);
Callable<String> task = new Callable<String>() {
public String call() throws Exception {
start.await();
return store.addResourceReference(key,
new SharedCacheResourceReference(id, user));
}
};
futures.add(exec.submit(task));
}
// start them all at the same time
start.countDown();
// check the result
Set<String> results = new HashSet<String>();
for (Future<String> future: futures) {
results.add(future.get());
}
// they should all have the same file name
assertSame(1, results.size());
assertEquals(Collections.singleton(fileName), results);
// there should be 5 refs as a result
Collection<SharedCacheResourceReference> refs = store.getResourceReferences(key);
assertSame(count, refs.size());
exec.shutdown();
}
@Test
public void testAddResourceRefAddResourceConcurrency() throws Exception {
startEmptyStore();
final String key = "key1";
final String fileName = "foo.jar";
final String user = "user";
final ApplicationId id = createAppId(1, 1L);
// add the resource and add the resource ref at the same time
ExecutorService exec = Executors.newFixedThreadPool(2);
final CountDownLatch start = new CountDownLatch(1);
Callable<String> addKeyTask = new Callable<String>() {
public String call() throws Exception {
start.await();
return store.addResource(key, fileName);
}
};
Callable<String> addAppIdTask = new Callable<String>() {
public String call() throws Exception {
start.await();
return store.addResourceReference(key,
new SharedCacheResourceReference(id, user));
}
};
Future<String> addAppIdFuture = exec.submit(addAppIdTask);
Future<String> addKeyFuture = exec.submit(addKeyTask);
// start them at the same time
start.countDown();
// get the results
String addKeyResult = addKeyFuture.get();
String addAppIdResult = addAppIdFuture.get();
assertEquals(fileName, addKeyResult);
System.out.println("addAppId() result: " + addAppIdResult);
// it may be null or the fileName depending on the timing
assertTrue(addAppIdResult == null || addAppIdResult.equals(fileName));
exec.shutdown();
}
@Test
public void testRemoveRef() throws Exception {
startEmptyStore();
String key = "key1";
String fileName = "foo.jar";
String user = "user";
// first add the resource
store.addResource(key, fileName);
// add a ref
ApplicationId id = createAppId(1, 1L);
SharedCacheResourceReference myRef = new SharedCacheResourceReference(id, user);
String result = store.addResourceReference(key, myRef);
assertEquals(fileName, result);
Collection<SharedCacheResourceReference> refs = store.getResourceReferences(key);
assertSame(1, refs.size());
assertEquals(Collections.singleton(myRef), refs);
// remove the same ref
store.removeResourceReferences(key, Collections.singleton(myRef), true);
Collection<SharedCacheResourceReference> newRefs = store.getResourceReferences(key);
assertTrue(newRefs == null || newRefs.isEmpty());
}
@Test
public void testBootstrapping() throws Exception {
Map<String, String> initialCachedResources = startStoreWithResources();
int count = initialCachedResources.size();
ApplicationId id = createAppId(1, 1L);
// the entries from the cached entries should now exist
for (int i = 0; i < count; i++) {
String key = String.valueOf(i);
String fileName = key + ".jar";
String result =
store.addResourceReference(key, new SharedCacheResourceReference(id,
"user"));
// the value should not be null (i.e. it has the key) and the filename should match
assertEquals(fileName, result);
// the initial input should be emptied
assertTrue(initialCachedResources.isEmpty());
}
}
@Test
public void testEvictableWithInitialApps() throws Exception {
startStoreWithApps();
assertFalse(store.isResourceEvictable("key", mock(FileStatus.class)));
}
private ApplicationId createAppId(int id, long timestamp) {
return ApplicationId.newInstance(timestamp, id);
}
class DummyAppChecker extends AppChecker {
@Override
@Private
public boolean isApplicationActive(ApplicationId id) throws YarnException {
// stub
return false;
}
@Override
@Private
public Collection<ApplicationId> getActiveApplications()
throws YarnException {
// stub
return null;
}
}
}