Package org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources

Class CGroupElasticMemoryController

java.lang.Object

java.lang.Thread

org.apache.hadoop.util.concurrent.SubjectInheritingThread

org.apache.hadoop.yarn.server.nodemanager.containermanager.linux.resources.CGroupElasticMemoryController

All Implemented Interfaces:

Runnable

public class CGroupElasticMemoryController
extends org.apache.hadoop.util.concurrent.SubjectInheritingThread

This thread controls memory usage using cgroups. It listens to out of memory events of all the containers together, and if we go over the limit picks a container to kill. The algorithm that picks the container is a plugin.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Thread

Thread.State, Thread.UncaughtExceptionHandler

Field Summary

Fields

Modifier and Type	Field	Description
protected static final org.slf4j.Logger	LOG

Fields inherited from class java.lang.Thread

MAX_PRIORITY, MIN_PRIORITY, NORM_PRIORITY

Constructor Summary

Constructors

Constructor	Description
CGroupElasticMemoryController(org.apache.hadoop.conf.Configuration conf, Context context, CGroupsHandler cgroups, boolean controlPhysicalMemory, boolean controlVirtualMemory, long limit)	Default constructor.

Method Summary

Modifier and Type	Method	Description
static boolean	isAvailable()	Checks if the CGroupElasticMemoryController is available on this system.
void	stopListening()	Stop listening to the cgroup.
void	work()	Main OOM listening thread.

Methods inherited from class org.apache.hadoop.util.concurrent.SubjectInheritingThread

run, start

Methods inherited from class java.lang.Thread

activeCount, checkAccess, clone, countStackFrames, currentThread, dumpStack, enumerate, getAllStackTraces, getContextClassLoader, getDefaultUncaughtExceptionHandler, getId, getName, getPriority, getStackTrace, getState, getThreadGroup, getUncaughtExceptionHandler, holdsLock, interrupt, interrupted, isAlive, isDaemon, isInterrupted, join, join, join, onSpinWait, resume, setContextClassLoader, setDaemon, setDefaultUncaughtExceptionHandler, setName, setPriority, setUncaughtExceptionHandler, sleep, sleep, stop, suspend, toString, yield

Methods inherited from class java.lang.Object

equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

LOG

protected static final org.slf4j.Logger LOG

Constructor Details

CGroupElasticMemoryController

public CGroupElasticMemoryController(org.apache.hadoop.conf.Configuration conf,
 Context context,
 CGroupsHandler cgroups,
 boolean controlPhysicalMemory,
 boolean controlVirtualMemory,
 long limit)
                              throws org.apache.hadoop.yarn.exceptions.YarnException

Default constructor.

Parameters:

conf - Yarn configuration to use

context - Node manager context to out of memory handler

cgroups - Cgroups handler configured

controlPhysicalMemory - Whether to listen to physical memory OOM

controlVirtualMemory - Whether to listen to virtual memory OOM

limit - memory limit in bytes

Throws:

org.apache.hadoop.yarn.exceptions.YarnException - Could not instantiate class

Method Details

stopListening

public void stopListening()

Stop listening to the cgroup.

isAvailable

public static boolean isAvailable()

Checks if the CGroupElasticMemoryController is available on this system. This assumes that Linux container executor is already initialized. We need to have CGroups enabled.

Returns:

True if CGroupElasticMemoryController is available. False otherwise.

work

public void work()

Main OOM listening thread. It uses an external process to listen to Linux events. The external process does not need to run as root, so it is not related to container-executor. We do not use JNI for security reasons.

Overrides:

work in class org.apache.hadoop.util.concurrent.SubjectInheritingThread