/**
* 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.mapred;
import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.TreeSet;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.mapreduce.TaskType;
import org.apache.hadoop.metrics.MetricsContext;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.w3c.dom.Text;
import org.xml.sax.SAXException;
/**
* Maintains a list of pools as well as scheduling parameters for each pool,
* such as guaranteed share allocations, from the fair scheduler config file.
*/
public class PoolManager {
public static final Log LOG = LogFactory.getLog(
"org.apache.hadoop.mapred.PoolManager");
/** Time to wait between checks of the allocation file */
public static final long ALLOC_RELOAD_INTERVAL = 10 * 1000;
/**
* Time to wait after the allocation has been modified before reloading it
* (this is done to prevent loading a file that hasn't been fully written).
*/
public static final long ALLOC_RELOAD_WAIT = 5 * 1000;
public static final String EXPLICIT_POOL_PROPERTY = "mapred.fairscheduler.pool";
private final FairScheduler scheduler;
// Map and reduce minimum allocations for each pool
private Map<String, Integer> mapAllocs = new HashMap<String, Integer>();
private Map<String, Integer> reduceAllocs = new HashMap<String, Integer>();
// If set, cap number of map and reduce tasks in a pool
private Map<String, Integer> poolMaxMaps = new HashMap<String, Integer>();
private Map<String, Integer> poolMaxReduces = new HashMap<String, Integer>();
// Sharing weights for each pool
private Map<String, Double> poolWeights = new HashMap<String, Double>();
// Max concurrent running jobs for each pool and for each user; in addition,
// for users that have no max specified, we use the userMaxJobsDefault.
private Map<String, Integer> poolMaxJobs = new HashMap<String, Integer>();
private Map<String, Integer> userMaxJobs = new HashMap<String, Integer>();
private int userMaxJobsDefault = Integer.MAX_VALUE;
private int poolMaxJobsDefault = Integer.MAX_VALUE;
// Min share preemption timeout for each pool in seconds. If a job in the pool
// waits this long without receiving its guaranteed share, it is allowed to
// preempt other jobs' tasks.
private Map<String, Long> minSharePreemptionTimeouts =
new HashMap<String, Long>();
// Default min share preemption timeout for pools where it is not set
// explicitly.
private long defaultMinSharePreemptionTimeout = Long.MAX_VALUE;
// Preemption timeout for jobs below fair share in seconds. If a job remains
// below half its fair share for this long, it is allowed to preempt tasks.
private long fairSharePreemptionTimeout = Long.MAX_VALUE;
SchedulingMode defaultSchedulingMode = SchedulingMode.FAIR;
private Object allocFile; // Path to XML file containing allocations. This
// is either a URL to specify a classpath resource
// (if the fair-scheduler.xml on the classpath is
// used) or a String to specify an absolute path (if
// mapred.fairscheduler.allocation.file is used).
private String poolNameProperty; // Jobconf property to use for determining a
// job's pool name (default: user.name)
private Map<String, Pool> pools = new HashMap<String, Pool>();
private long lastReloadAttempt; // Last time we tried to reload the pools file
private long lastSuccessfulReload; // Last time we successfully reloaded pools
private boolean lastReloadAttemptFailed = false;
private Set<String> declaredPools = new TreeSet<String>();
public PoolManager(FairScheduler scheduler) {
this.scheduler = scheduler;
}
public void initialize() throws IOException, SAXException,
AllocationConfigurationException, ParserConfigurationException {
Configuration conf = scheduler.getConf();
this.poolNameProperty = conf.get(
"mapred.fairscheduler.poolnameproperty", "user.name");
this.allocFile = conf.get("mapred.fairscheduler.allocation.file");
if (allocFile == null) {
// No allocation file specified in jobconf. Use the default allocation
// file, fair-scheduler.xml, looking for it on the classpath.
allocFile = new Configuration().getResource("fair-scheduler.xml");
if (allocFile == null) {
LOG.error("The fair scheduler allocation file fair-scheduler.xml was "
+ "not found on the classpath, and no other config file is given "
+ "through mapred.fairscheduler.allocation.file.");
}
}
reloadAllocs();
lastSuccessfulReload = System.currentTimeMillis();
lastReloadAttempt = System.currentTimeMillis();
// Create the default pool so that it shows up in the web UI
getPool(Pool.DEFAULT_POOL_NAME);
}
/**
* Get a pool by name, creating it if necessary
*/
public synchronized Pool getPool(String name) {
Pool pool = pools.get(name);
if (pool == null) {
pool = new Pool(scheduler, name);
pool.setSchedulingMode(defaultSchedulingMode);
pools.put(name, pool);
}
return pool;
}
/**
* Get the pool that a given job is in.
*/
public Pool getPool(JobInProgress job) {
return getPool(getPoolName(job));
}
/**
* Reload allocations file if it hasn't been loaded in a while
*/
public void reloadAllocsIfNecessary() {
long time = System.currentTimeMillis();
if (time > lastReloadAttempt + ALLOC_RELOAD_INTERVAL) {
lastReloadAttempt = time;
if (null == allocFile) {
return;
}
try {
// Get last modified time of alloc file depending whether it's a String
// (for a path name) or an URL (for a classloader resource)
long lastModified;
if (allocFile instanceof String) {
File file = new File((String) allocFile);
lastModified = file.lastModified();
} else { // allocFile is an URL
URLConnection conn = ((URL) allocFile).openConnection();
lastModified = conn.getLastModified();
}
if (lastModified > lastSuccessfulReload &&
time > lastModified + ALLOC_RELOAD_WAIT) {
reloadAllocs();
lastSuccessfulReload = time;
lastReloadAttemptFailed = false;
}
} catch (Exception e) {
// Throwing the error further out here won't help - the RPC thread
// will catch it and report it in a loop. Instead, just log it and
// hope somebody will notice from the log.
// We log the error only on the first failure so we don't fill up the
// JobTracker's log with these messages.
if (!lastReloadAttemptFailed) {
LOG.error("Failed to reload fair scheduler config file - " +
"will use existing allocations.", e);
}
lastReloadAttemptFailed = true;
}
}
}
/**
* Updates the allocation list from the allocation config file. This file is
* expected to be in the following whitespace-separated format:
*
* <code>
* poolName1 mapAlloc reduceAlloc
* poolName2 mapAlloc reduceAlloc
* ...
* </code>
*
* Blank lines and lines starting with # are ignored.
*
* @throws IOException if the config file cannot be read.
* @throws AllocationConfigurationException if allocations are invalid.
* @throws ParserConfigurationException if XML parser is misconfigured.
* @throws SAXException if config file is malformed.
*/
public void reloadAllocs() throws IOException, ParserConfigurationException,
SAXException, AllocationConfigurationException {
if (allocFile == null) return;
// Create some temporary hashmaps to hold the new allocs, and we only save
// them in our fields if we have parsed the entire allocs file successfully.
Map<String, Integer> mapAllocs = new HashMap<String, Integer>();
Map<String, Integer> reduceAllocs = new HashMap<String, Integer>();
Map<String, Integer> poolMaxJobs = new HashMap<String, Integer>();
Map<String, Integer> userMaxJobs = new HashMap<String, Integer>();
Map<String, Integer> poolMaxMaps = new HashMap<String, Integer>();
Map<String, Integer> poolMaxReduces = new HashMap<String, Integer>();
Map<String, Double> poolWeights = new HashMap<String, Double>();
Map<String, SchedulingMode> poolModes = new HashMap<String, SchedulingMode>();
Map<String, Long> minSharePreemptionTimeouts = new HashMap<String, Long>();
int userMaxJobsDefault = Integer.MAX_VALUE;
int poolMaxJobsDefault = Integer.MAX_VALUE;
long fairSharePreemptionTimeout = Long.MAX_VALUE;
long defaultMinSharePreemptionTimeout = Long.MAX_VALUE;
SchedulingMode defaultSchedulingMode = SchedulingMode.FAIR;
// Remember all pool names so we can display them on web UI, etc.
List<String> poolNamesInAllocFile = new ArrayList<String>();
// Read and parse the allocations file.
DocumentBuilderFactory docBuilderFactory =
DocumentBuilderFactory.newInstance();
docBuilderFactory.setIgnoringComments(true);
DocumentBuilder builder = docBuilderFactory.newDocumentBuilder();
Document doc;
if (allocFile instanceof String) {
doc = builder.parse(new File((String) allocFile));
} else {
doc = builder.parse(allocFile.toString());
}
Element root = doc.getDocumentElement();
if (!"allocations".equals(root.getTagName()))
throw new AllocationConfigurationException("Bad fair scheduler config " +
"file: top-level element not <allocations>");
NodeList elements = root.getChildNodes();
for (int i = 0; i < elements.getLength(); i++) {
Node node = elements.item(i);
if (!(node instanceof Element))
continue;
Element element = (Element)node;
if ("pool".equals(element.getTagName())) {
String poolName = element.getAttribute("name");
poolNamesInAllocFile.add(poolName);
NodeList fields = element.getChildNodes();
for (int j = 0; j < fields.getLength(); j++) {
Node fieldNode = fields.item(j);
if (!(fieldNode instanceof Element))
continue;
Element field = (Element) fieldNode;
if ("minMaps".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
mapAllocs.put(poolName, val);
} else if ("minReduces".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
reduceAllocs.put(poolName, val);
} else if ("maxMaps".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
poolMaxMaps.put(poolName, val);
} else if ("maxReduces".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
poolMaxReduces.put(poolName, val);
} else if ("maxRunningJobs".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
poolMaxJobs.put(poolName, val);
} else if ("weight".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
double val = Double.parseDouble(text);
poolWeights.put(poolName, val);
} else if ("minSharePreemptionTimeout".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
long val = Long.parseLong(text) * 1000L;
minSharePreemptionTimeouts.put(poolName, val);
} else if ("schedulingMode".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
poolModes.put(poolName, parseSchedulingMode(text));
}
}
if (poolMaxMaps.containsKey(poolName) && mapAllocs.containsKey(poolName)
&& poolMaxMaps.get(poolName) < mapAllocs.get(poolName)) {
LOG.warn(String.format("Pool %s has max maps %d less than min maps %d",
poolName, poolMaxMaps.get(poolName), mapAllocs.get(poolName)));
}
if(poolMaxReduces.containsKey(poolName) && reduceAllocs.containsKey(poolName)
&& poolMaxReduces.get(poolName) < reduceAllocs.get(poolName)) {
LOG.warn(String.format("Pool %s has max reduces %d less than min reduces %d",
poolName, poolMaxReduces.get(poolName), reduceAllocs.get(poolName)));
}
} else if ("user".equals(element.getTagName())) {
String userName = element.getAttribute("name");
NodeList fields = element.getChildNodes();
for (int j = 0; j < fields.getLength(); j++) {
Node fieldNode = fields.item(j);
if (!(fieldNode instanceof Element))
continue;
Element field = (Element) fieldNode;
if ("maxRunningJobs".equals(field.getTagName())) {
String text = ((Text)field.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
userMaxJobs.put(userName, val);
}
}
} else if ("userMaxJobsDefault".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
userMaxJobsDefault = val;
} else if ("poolMaxJobsDefault".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
int val = Integer.parseInt(text);
poolMaxJobsDefault = val;
} else if ("fairSharePreemptionTimeout".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
long val = Long.parseLong(text) * 1000L;
fairSharePreemptionTimeout = val;
} else if ("defaultMinSharePreemptionTimeout".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
long val = Long.parseLong(text) * 1000L;
defaultMinSharePreemptionTimeout = val;
} else if ("defaultPoolSchedulingMode".equals(element.getTagName())) {
String text = ((Text)element.getFirstChild()).getData().trim();
defaultSchedulingMode = parseSchedulingMode(text);
} else {
LOG.warn("Bad element in allocations file: " + element.getTagName());
}
}
// Commit the reload; also create any pool defined in the alloc file
// if it does not already exist, so it can be displayed on the web UI.
synchronized(this) {
this.mapAllocs = mapAllocs;
this.reduceAllocs = reduceAllocs;
this.poolMaxMaps = poolMaxMaps;
this.poolMaxReduces = poolMaxReduces;
this.poolMaxJobs = poolMaxJobs;
this.userMaxJobs = userMaxJobs;
this.poolWeights = poolWeights;
this.minSharePreemptionTimeouts = minSharePreemptionTimeouts;
this.userMaxJobsDefault = userMaxJobsDefault;
this.poolMaxJobsDefault = poolMaxJobsDefault;
this.fairSharePreemptionTimeout = fairSharePreemptionTimeout;
this.defaultMinSharePreemptionTimeout = defaultMinSharePreemptionTimeout;
this.defaultSchedulingMode = defaultSchedulingMode;
this.declaredPools = Collections.unmodifiableSet(new TreeSet<String>(
poolNamesInAllocFile));
for (String name: poolNamesInAllocFile) {
Pool pool = getPool(name);
if (poolModes.containsKey(name)) {
pool.setSchedulingMode(poolModes.get(name));
} else {
pool.setSchedulingMode(defaultSchedulingMode);
}
}
}
}
/**
* Does the pool have incompatible max and min allocation set.
*
* @param type
* {@link TaskType#MAP} or {@link TaskType#REDUCE}
* @param pool
* the pool name
* @return true if the max is less than the min
*/
boolean invertedMinMax(TaskType type, String pool) {
Map<String, Integer> max = TaskType.MAP == type ? poolMaxMaps : poolMaxReduces;
Map<String, Integer> min = TaskType.MAP == type ? mapAllocs : reduceAllocs;
if (max.containsKey(pool) && min.containsKey(pool)
&& max.get(pool) < min.get(pool)) {
return true;
}
return false;
}
private SchedulingMode parseSchedulingMode(String text)
throws AllocationConfigurationException {
text = text.toLowerCase();
if (text.equals("fair")) {
return SchedulingMode.FAIR;
} else if (text.equals("fifo")) {
return SchedulingMode.FIFO;
} else {
throw new AllocationConfigurationException(
"Unknown scheduling mode : " + text + "; expected 'fifo' or 'fair'");
}
}
/**
* Get the allocation for a particular pool
*/
public int getAllocation(String pool, TaskType taskType) {
Map<String, Integer> allocationMap = (taskType == TaskType.MAP ?
mapAllocs : reduceAllocs);
Integer alloc = allocationMap.get(pool);
return (alloc == null ? 0 : alloc);
}
/**
* Get the maximum map or reduce slots for the given pool.
* @return the cap set on this pool, or Integer.MAX_VALUE if not set.
*/
int getMaxSlots(String poolName, TaskType taskType) {
Map<String, Integer> maxMap = (taskType == TaskType.MAP ? poolMaxMaps : poolMaxReduces);
if (maxMap.containsKey(poolName)) {
return maxMap.get(poolName);
} else {
return Integer.MAX_VALUE;
}
}
/**
* Add a job in the appropriate pool
*/
public synchronized void addJob(JobInProgress job) {
getPool(getPoolName(job)).addJob(job);
}
/**
* Remove a job
*/
public synchronized void removeJob(JobInProgress job) {
getPool(getPoolName(job)).removeJob(job);
}
/**
* Change the pool of a particular job
*/
public synchronized void setPool(JobInProgress job, String pool) {
removeJob(job);
job.getJobConf().set(EXPLICIT_POOL_PROPERTY, pool);
addJob(job);
}
/**
* Get a collection of all pools
*/
public synchronized Collection<Pool> getPools() {
return pools.values();
}
/**
* Get the pool name for a JobInProgress from its configuration. This uses
* the value of mapred.fairscheduler.pool if specified, otherwise the value
* of the property named in mapred.fairscheduler.poolnameproperty if that is
* specified. Otherwise if neither is specified it uses the "user.name" property
* in the jobconf by default.
*/
public String getPoolName(JobInProgress job) {
Configuration conf = job.getJobConf();
return conf.get(EXPLICIT_POOL_PROPERTY,
conf.get(poolNameProperty, Pool.DEFAULT_POOL_NAME)).trim();
}
/**
* Get all pool names that have been seen either in the allocation file or in
* a MapReduce job.
*/
public synchronized Collection<String> getPoolNames() {
List<String> list = new ArrayList<String>();
for (Pool pool: getPools()) {
list.add(pool.getName());
}
Collections.sort(list);
return list;
}
public int getUserMaxJobs(String user) {
if (userMaxJobs.containsKey(user)) {
return userMaxJobs.get(user);
} else {
return userMaxJobsDefault;
}
}
public int getPoolMaxJobs(String pool) {
if (poolMaxJobs.containsKey(pool)) {
return poolMaxJobs.get(pool);
} else {
return poolMaxJobsDefault;
}
}
public double getPoolWeight(String pool) {
if (poolWeights.containsKey(pool)) {
return poolWeights.get(pool);
} else {
return 1.0;
}
}
/**
* Get a pool's min share preemption timeout, in milliseconds. This is the
* time after which jobs in the pool may kill other pools' tasks if they
* are below their min share.
*/
public long getMinSharePreemptionTimeout(String pool) {
if (minSharePreemptionTimeouts.containsKey(pool)) {
return minSharePreemptionTimeouts.get(pool);
} else {
return defaultMinSharePreemptionTimeout;
}
}
/**
* Get the fair share preemption, in milliseconds. This is the time
* after which any job may kill other jobs' tasks if it is below half
* its fair share.
*/
public long getFairSharePreemptionTimeout() {
return fairSharePreemptionTimeout;
}
synchronized void updateMetrics() {
for (Pool pool : pools.values()) {
pool.updateMetrics();
}
}
public synchronized Set<String> getDeclaredPools() {
return declaredPools;
}
}