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

Class FairScheduler

java.lang.Object

org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler

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 AbstractYarnScheduler

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

Fields

Modifier and Type	Field and Description
protected boolean	assignMultiple
static org.apache.hadoop.yarn.api.records.Resource	CONTAINER_RESERVED
protected boolean	continuousSchedulingEnabled
protected int	continuousSchedulingSleepMs
protected long	lastPreemptionUpdateTime
protected int	maxAssign
protected long	nodeLocalityDelayMs
protected double	nodeLocalityThreshold
protected boolean	preemptionEnabled
protected long	preemptionInterval
protected long	rackLocalityDelayMs
protected double	rackLocalityThreshold
protected boolean	sizeBasedWeight
protected long	UPDATE_INTERVAL
protected long	waitTimeBeforeKill
protected WeightAdjuster	weightAdjuster

Fields inherited from class org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler

applications, EMPTY_ALLOCATION, EMPTY_CONTAINER_LIST, rmContext

Constructor Summary

Constructors

Constructor and Description
FairScheduler()

Method Summary

Methods

Modifier and Type	Method and Description
protected void	addApplication(org.apache.hadoop.yarn.api.records.ApplicationId applicationId, String queueName, String user) Add a new application to the scheduler, with a given id, queue name, and user.
protected void	addApplicationAttempt(org.apache.hadoop.yarn.api.records.ApplicationAttemptId applicationAttemptId, boolean transferStateFromPreviousAttempt) Add a new application attempt to the scheduler.
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.
AllocationConfiguration	getAllocationConfiguration()
org.apache.hadoop.yarn.api.records.ApplicationResourceUsageReport	getAppResourceUsageReport(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId) Get a resource usage report from a given app attempt ID.
List<org.apache.hadoop.yarn.api.records.ApplicationAttemptId>	getAppsInQueue(String queueName) Gets the apps under a given queue
ResourceWeights	getAppWeight(AppSchedulable app)
org.apache.hadoop.yarn.util.Clock	getClock()
org.apache.hadoop.yarn.api.records.Resource	getClusterCapacity()
FairSchedulerConfiguration	getConf()
RMContainerTokenSecretManager	getContainerTokenSecretManager()
int	getContinuousSchedulingSleepMs()
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.
long	getNodeLocalityDelayMs()
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.
long	getRackLocalityDelayMs()
double	getRackLocalityThreshold()
RMContainer	getRMContainer(org.apache.hadoop.yarn.api.records.ContainerId containerId) Get the container for the given containerId.
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)
boolean	isContinuousSchedulingEnabled()
String	moveApplication(org.apache.hadoop.yarn.api.records.ApplicationId appId, String queueName) Moves the given application to the given queue
protected void	preemptResources(Collection<FSLeafQueue> scheds, HashMap<AppSchedulable,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 HashMap<AppSchedulable,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 org.apache.hadoop.yarn.server.resourcemanager.scheduler.AbstractYarnScheduler

getSchedulerApplications, getTransferredContainers

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

preemptionInterval

protected long preemptionInterval

waitTimeBeforeKill

protected long waitTimeBeforeKill

preemptionEnabled

protected boolean preemptionEnabled

sizeBasedWeight

protected boolean sizeBasedWeight

weightAdjuster

protected WeightAdjuster weightAdjuster

continuousSchedulingEnabled

protected boolean continuousSchedulingEnabled

continuousSchedulingSleepMs

protected int continuousSchedulingSleepMs

nodeLocalityThreshold

protected double nodeLocalityThreshold

rackLocalityThreshold

protected double rackLocalityThreshold

nodeLocalityDelayMs

protected long nodeLocalityDelayMs

rackLocalityDelayMs

protected long rackLocalityDelayMs

assignMultiple

protected boolean assignMultiple

maxAssign

protected int maxAssign

Constructor Detail

FairScheduler

public FairScheduler()

Method Detail

getConf

public FairSchedulerConfiguration getConf()

getQueueManager

public QueueManager getQueueManager()

getRMContainer

public RMContainer getRMContainer(org.apache.hadoop.yarn.api.records.ContainerId containerId)

Description copied from interface: YarnScheduler

Get the container for the given containerId.

Returns:

the container for the given containerId.

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,
                    HashMap<AppSchedulable,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 HashMap<AppSchedulable,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.

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.

Returns:

maximum allocatable resource

getNodeLocalityThreshold

public double getNodeLocalityThreshold()

getRackLocalityThreshold

public double getRackLocalityThreshold()

getNodeLocalityDelayMs

public long getNodeLocalityDelayMs()

getRackLocalityDelayMs

public long getRackLocalityDelayMs()

isContinuousSchedulingEnabled

public boolean isContinuousSchedulingEnabled()

getContinuousSchedulingSleepMs

public int getContinuousSchedulingSleepMs()

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.ApplicationId applicationId,
                  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.

addApplicationAttempt

protected void addApplicationAttempt(org.apache.hadoop.yarn.api.records.ApplicationAttemptId applicationAttemptId,
                         boolean transferStateFromPreviousAttempt)

Add a new application attempt to the scheduler.

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.

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.

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.

Parameters:

appAttemptId - the id of the application attempt

Returns:

SchedulerApp for this given attempt.

getAppResourceUsageReport

public org.apache.hadoop.yarn.api.records.ApplicationResourceUsageReport getAppResourceUsageReport(org.apache.hadoop.yarn.api.records.ApplicationAttemptId appAttemptId)

Description copied from interface: YarnScheduler

Get a resource usage report from a given app attempt ID.

Parameters:

appAttemptId - the id of the application attempt

Returns:

resource usage report for this given attempt

getRootQueueMetrics

public QueueMetrics getRootQueueMetrics()

Description copied from interface: YarnScheduler

Get the root queue for the scheduler.

Returns:

the root queue for the scheduler.

handle

public void handle(SchedulerEvent event)

recover

public void recover(RMStateStore.RMState state)
             throws Exception

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.

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

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.

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.

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

Returns:

true if the user has the permission, false otherwise

getAllocationConfiguration

public AllocationConfiguration getAllocationConfiguration()

getAppsInQueue

public List<org.apache.hadoop.yarn.api.records.ApplicationAttemptId> getAppsInQueue(String queueName)

Description copied from interface: YarnScheduler

Gets the apps under a given queue

Parameters:

queueName - the name of the queue.

Returns:

a collection of app attempt ids in the given queue.

moveApplication

public String moveApplication(org.apache.hadoop.yarn.api.records.ApplicationId appId,
                     String queueName)
                       throws org.apache.hadoop.yarn.exceptions.YarnException

Description copied from interface: YarnScheduler

Moves the given application to the given queue

Specified by:

moveApplication in interface YarnScheduler

Overrides:

moveApplication in class AbstractYarnScheduler

Returns:

the name of the queue the application was placed into

Throws:

org.apache.hadoop.yarn.exceptions.YarnException - if the move cannot be carried out