org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair
Class FairScheduler

java.lang.Object
  org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairScheduler

All Implemented Interfaces:

org.apache.hadoop.yarn.event.EventHandler<SchedulerEvent>, Recoverable, ResourceScheduler, YarnScheduler

@InterfaceAudience.LimitedPrivate(value="yarn")
@InterfaceStability.Unstable
public class FairScheduler
extends Object
implements ResourceScheduler

A scheduler that schedules resources between a set of queues. The scheduler keeps track of the resources used by each queue, and attempts to maintain fairness by scheduling tasks at queues whose allocations are farthest below an ideal fair distribution. The fair scheduler supports hierarchical queues. All queues descend from a queue named "root". Available resources are distributed among the children of the root queue in the typical fair scheduling fashion. Then, the children distribute the resources assigned to them to their children in the same fashion. Applications may only be scheduled on leaf queues. Queues can be specified as children of other queues by placing them as sub-elements of their parents in the fair scheduler configuration file. A queue's name starts with the names of its parents, with periods as separators. So a queue named "queue1" under the root named, would be referred to as "root.queue1", and a queue named "queue2" under a queue named "parent1" would be referred to as "root.parent1.queue2".

Field Summary

protected Map<org.apache.hadoop.yarn.api.records.ApplicationAttemptId,FSSchedulerApp>	applications
protected boolean	assignMultiple
static org.apache.hadoop.yarn.api.records.Resource	CONTAINER_RESERVED
protected long	lastPreemptionUpdateTime
protected int	maxAssign
protected double	nodeLocalityThreshold
protected boolean	preemptionEnabled
protected long	preemptionInterval
protected double	rackLocalityThreshold
protected boolean	sizeBasedWeight
protected long	UPDATE_INTERVAL
protected long	waitTimeBeforeKill
protected WeightAdjuster	weightAdjuster

Constructor Summary

FairScheduler()

Method Summary

protected void	addApplication(org.apache.hadoop.yarn.api.records.ApplicationAttemptId applicationAttemptId, String queueName, String user) Add a new application to the scheduler, with a given id, queue name, and user.
Allocation	allocate(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId, List<org.apache.hadoop.yarn.api.records.ResourceRequest> ask, List<org.apache.hadoop.yarn.api.records.ContainerId> release, List<String> blacklistAdditions, List<String> blacklistRemovals) The main api between the ApplicationMaster and the Scheduler.
boolean	checkAccess(org.apache.hadoop.security.UserGroupInformation callerUGI, org.apache.hadoop.yarn.api.records.QueueACL acl, String queueName) Check if the user has permission to perform the operation.
ResourceWeights	getAppWeight(AppSchedulable app)
org.apache.hadoop.yarn.util.Clock	getClock()
org.apache.hadoop.yarn.api.records.Resource	getClusterCapacity()
FairSchedulerConfiguration	getConf()
RMContainerTokenSecretManager	getContainerTokenSecretManager()
org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairSchedulerEventLog	getEventLog()
org.apache.hadoop.yarn.api.records.Resource	getIncrementResourceCapability()
org.apache.hadoop.yarn.api.records.Resource	getMaximumResourceCapability() Get maximum allocatable Resource.
org.apache.hadoop.yarn.api.records.Resource	getMinimumResourceCapability() Get minimum allocatable Resource.
double	getNodeLocalityThreshold()
SchedulerNodeReport	getNodeReport(org.apache.hadoop.yarn.api.records.NodeId nodeId) Get node resource usage report.
int	getNumClusterNodes() Get the number of nodes available in the cluster.
org.apache.hadoop.yarn.api.records.QueueInfo	getQueueInfo(String queueName, boolean includeChildQueues, boolean recursive) Get queue information
QueueManager	getQueueManager()
List<org.apache.hadoop.yarn.api.records.QueueUserACLInfo>	getQueueUserAclInfo() Get acls for queues for current user.
double	getRackLocalityThreshold()
QueueMetrics	getRootQueueMetrics() Get the root queue for the scheduler.
FSSchedulerApp	getSchedulerApp(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId)
SchedulerAppReport	getSchedulerAppInfo(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId) Get the Scheduler app for a given app attempt Id.
void	handle(SchedulerEvent event)
protected void	preemptResources(Collection<FSLeafQueue> scheds, org.apache.hadoop.yarn.api.records.Resource toPreempt) Preempt a quantity of resources from a list of QueueSchedulables.
protected void	preemptTasksIfNecessary() Check for queues that need tasks preempted, either because they have been below their guaranteed share for minSharePreemptionTimeout or they have been below half their fair share for the fairSharePreemptionTimeout.
void	recover(RMStateStore.RMState state)
void	reinitialize(org.apache.hadoop.conf.Configuration conf, RMContext rmContext) Re-initialize the ResourceScheduler.
protected org.apache.hadoop.yarn.api.records.Resource	resToPreempt(FSLeafQueue sched, long curTime) Return the resource amount that this queue is allowed to preempt, if any.
protected void	setClock(org.apache.hadoop.yarn.util.Clock clock)
protected void	update() Recompute the internal variables used by the scheduler - per-job weights, fair shares, deficits, minimum slot allocations, and amount of used and required resources per job.

Methods inherited from class java.lang.Object

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

Field Detail

CONTAINER_RESERVED

public static final org.apache.hadoop.yarn.api.records.Resource CONTAINER_RESERVED

UPDATE_INTERVAL

protected long UPDATE_INTERVAL

lastPreemptionUpdateTime

protected long lastPreemptionUpdateTime

applications

protected Map<org.apache.hadoop.yarn.api.records.ApplicationAttemptId,FSSchedulerApp> applications

preemptionInterval

protected long preemptionInterval

waitTimeBeforeKill

protected long waitTimeBeforeKill

preemptionEnabled

protected boolean preemptionEnabled

sizeBasedWeight

protected boolean sizeBasedWeight

weightAdjuster

protected WeightAdjuster weightAdjuster

nodeLocalityThreshold

protected double nodeLocalityThreshold

rackLocalityThreshold

protected double rackLocalityThreshold

assignMultiple

protected boolean assignMultiple

maxAssign

protected int maxAssign

Constructor Detail

FairScheduler

public FairScheduler()

Method Detail

getConf

public FairSchedulerConfiguration getConf()

getQueueManager

public QueueManager getQueueManager()

update

protected void update()

Recompute the internal variables used by the scheduler - per-job weights, fair shares, deficits, minimum slot allocations, and amount of used and required resources per job.

preemptTasksIfNecessary

protected void preemptTasksIfNecessary()

Check for queues that need tasks preempted, either because they have been below their guaranteed share for minSharePreemptionTimeout or they have been below half their fair share for the fairSharePreemptionTimeout. If such queues exist, compute how many tasks of each type need to be preempted and then select the right ones using preemptTasks.

preemptResources

protected void preemptResources(Collection<FSLeafQueue> scheds,
                                org.apache.hadoop.yarn.api.records.Resource toPreempt)

Preempt a quantity of resources from a list of QueueSchedulables. The policy for this is to pick apps from queues that are over their fair share, but make sure that no queue is placed below its fair share in the process. We further prioritize preemption by choosing containers with lowest priority to preempt.

resToPreempt

protected org.apache.hadoop.yarn.api.records.Resource resToPreempt(FSLeafQueue sched,
                                                                   long curTime)

Return the resource amount that this queue is allowed to preempt, if any. If the queue has been below its min share for at least its preemption timeout, it should preempt the difference between its current share and this min share. If it has been below half its fair share for at least the fairSharePreemptionTimeout, it should preempt enough tasks to get up to its full fair share. If both conditions hold, we preempt the max of the two amounts (this shouldn't happen unless someone sets the timeouts to be identical for some reason).

getContainerTokenSecretManager

public RMContainerTokenSecretManager getContainerTokenSecretManager()

getAppWeight

public ResourceWeights getAppWeight(AppSchedulable app)

getMinimumResourceCapability

public org.apache.hadoop.yarn.api.records.Resource getMinimumResourceCapability()

Description copied from interface: YarnScheduler

Get minimum allocatable Resource.

Specified by:

getMinimumResourceCapability in interface YarnScheduler

Returns:

minimum allocatable resource

getIncrementResourceCapability

public org.apache.hadoop.yarn.api.records.Resource getIncrementResourceCapability()

getMaximumResourceCapability

public org.apache.hadoop.yarn.api.records.Resource getMaximumResourceCapability()

Description copied from interface: YarnScheduler

Get maximum allocatable Resource.

Specified by:

getMaximumResourceCapability in interface YarnScheduler

Returns:

maximum allocatable resource

getNodeLocalityThreshold

public double getNodeLocalityThreshold()

getRackLocalityThreshold

public double getRackLocalityThreshold()

getClusterCapacity

public org.apache.hadoop.yarn.api.records.Resource getClusterCapacity()

getClock

public org.apache.hadoop.yarn.util.Clock getClock()

setClock

protected void setClock(org.apache.hadoop.yarn.util.Clock clock)

getEventLog

public org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.FairSchedulerEventLog getEventLog()

addApplication

protected void addApplication(org.apache.hadoop.yarn.api.records.ApplicationAttemptId applicationAttemptId,
                              String queueName,
                              String user)

Add a new application to the scheduler, with a given id, queue name, and user. This will accept a new app even if the user or queue is above configured limits, but the app will not be marked as runnable.

allocate

public Allocation allocate(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId,
                           List<org.apache.hadoop.yarn.api.records.ResourceRequest> ask,
                           List<org.apache.hadoop.yarn.api.records.ContainerId> release,
                           List<String> blacklistAdditions,
                           List<String> blacklistRemovals)

Description copied from interface: YarnScheduler

The main api between the ApplicationMaster and the Scheduler. The ApplicationMaster is updating his future resource requirements and may release containers he doens't need.

Specified by:

allocate in interface YarnScheduler

Returns:

the Allocation for the application

getNodeReport

public SchedulerNodeReport getNodeReport(org.apache.hadoop.yarn.api.records.NodeId nodeId)

Description copied from interface: YarnScheduler

Get node resource usage report.

Specified by:

getNodeReport in interface YarnScheduler

Returns:

the SchedulerNodeReport for the node or null if nodeId does not point to a defined node.

getSchedulerApp

public FSSchedulerApp getSchedulerApp(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId)

getSchedulerAppInfo

public SchedulerAppReport getSchedulerAppInfo(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId)

Description copied from interface: YarnScheduler

Get the Scheduler app for a given app attempt Id.

Specified by:

getSchedulerAppInfo in interface YarnScheduler

Parameters:

appAttemptId - the id of the application attempt

Returns:

SchedulerApp for this given attempt.

getRootQueueMetrics

public QueueMetrics getRootQueueMetrics()

Description copied from interface: YarnScheduler

Get the root queue for the scheduler.

Specified by:

getRootQueueMetrics in interface YarnScheduler

Returns:

the root queue for the scheduler.

handle

public void handle(SchedulerEvent event)

Specified by:

handle in interface org.apache.hadoop.yarn.event.EventHandler<SchedulerEvent>

recover

public void recover(RMStateStore.RMState state)
             throws Exception

Specified by:

recover in interface Recoverable

Throws:

Exception

reinitialize

public void reinitialize(org.apache.hadoop.conf.Configuration conf,
                         RMContext rmContext)
                  throws IOException

Description copied from interface: ResourceScheduler

Re-initialize the ResourceScheduler.

Specified by:

reinitialize in interface ResourceScheduler

Parameters:

conf - configuration

Throws:

IOException

getQueueInfo

public org.apache.hadoop.yarn.api.records.QueueInfo getQueueInfo(String queueName,
                                                                 boolean includeChildQueues,
                                                                 boolean recursive)
                                                          throws IOException

Description copied from interface: YarnScheduler

Get queue information

Specified by:

getQueueInfo in interface YarnScheduler

Parameters:

queueName - queue name

includeChildQueues - include child queues?

recursive - get children queues?

Returns:

queue information

Throws:

IOException

getQueueUserAclInfo

public List<org.apache.hadoop.yarn.api.records.QueueUserACLInfo> getQueueUserAclInfo()

Description copied from interface: YarnScheduler

Get acls for queues for current user.

Specified by:

getQueueUserAclInfo in interface YarnScheduler

Returns:

acls for queues for current user

getNumClusterNodes

public int getNumClusterNodes()

Description copied from interface: YarnScheduler

Get the number of nodes available in the cluster.

Specified by:

getNumClusterNodes in interface YarnScheduler

Returns:

the number of available nodes.

checkAccess

public boolean checkAccess(org.apache.hadoop.security.UserGroupInformation callerUGI,
                           org.apache.hadoop.yarn.api.records.QueueACL acl,
                           String queueName)

Description copied from interface: YarnScheduler

Check if the user has permission to perform the operation. If the user has QueueACL.ADMINISTER_QUEUE permission, this user can view/modify the applications in this queue

Specified by:

checkAccess in interface YarnScheduler

Returns:

true if the user has the permission, false otherwise