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YARN-648. FS: Add documentation for pluggable policy. (kkambatl via tucu) 

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1492388 13f79535-47bb-0310-9956-ffa450edef68
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Alejandro Abdelnur 2013-06-12 19:24:23 +00:00
parent 1ed916f6c6
commit 1104c7d166
2 changed files with 42 additions and 32 deletions
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hadoop-yarn-project/CHANGES.txt
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@ -318,6 +318,8 @@ Release 2.1.0-beta - UNRELEASED
YARN-600. Hook up cgroups CPU settings to the number of virtual cores YARN-600. Hook up cgroups CPU settings to the number of virtual cores
allocated. (sandyr via tucu) allocated. (sandyr via tucu)
YARN-648. FS: Add documentation for pluggable policy. (kkambatl via tucu)
OPTIMIZATIONS OPTIMIZATIONS
YARN-512. Log aggregation root directory check is more expensive than it YARN-512. Log aggregation root directory check is more expensive than it

68
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/apt/FairScheduler.apt.vm
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@ -47,29 +47,14 @@ Hadoop MapReduce Next Generation - Fair Scheduler
The scheduler organizes apps further into "queues", and shares resources The scheduler organizes apps further into "queues", and shares resources
fairly between these queues. By default, all users share a single queue, fairly between these queues. By default, all users share a single queue,
called “default”. If an app specifically lists a queue in a container called “default”. If an app specifically lists a queue in a container resource
resource request, the request is submitted to that queue. It is also request, the request is submitted to that queue. It is also possible to assign
possible to assign queues based on the user name included with the request queues based on the user name included with the request through
through configuration. Within each queue, a scheduling policy is used to share configuration. Within each queue, a scheduling policy is used to share
resources between the running apps. The default is memory-based fair sharing, resources between the running apps. The default is memory-based fair sharing,
but FIFO and multi-resource with Dominant Resource Fairness can also be but FIFO and multi-resource with Dominant Resource Fairness can also be
configured. Queues can be configured with weights to share the cluster non-evenly. configured. Queues can be arranged in a hierarchy to divide resources and
configured with weights to share the cluster in specific proportions.
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". When
referring to queues, the root part of the name is optional, so queue1 could
be referred to as just "queue1", and a queue2 could be referred to as just
"parent1.queue2".
In addition to providing fair sharing, the Fair Scheduler allows assigning In addition to providing fair sharing, the Fair Scheduler allows assigning
guaranteed minimum shares to queues, which is useful for ensuring that guaranteed minimum shares to queues, which is useful for ensuring that
@ -87,9 +72,31 @@ Hadoop MapReduce Next Generation - Fair Scheduler
cause too much intermediate data to be created or too much context-switching. cause too much intermediate data to be created or too much context-switching.
Limiting the apps does not cause any subsequently submitted apps to fail, Limiting the apps does not cause any subsequently submitted apps to fail,
only to wait in the scheduler's queue until some of the user's earlier apps only to wait in the scheduler's queue until some of the user's earlier apps
finish. Apps to run from each user/queue are chosen in the same fair sharing finish.
manner, but can alternatively be configured to be chosen in order of submit
time, as in the default FIFO scheduler in Hadoop. * {Hierarchical queues with pluggable policies}
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". When referring to queues, the
root part of the name is optional, so queue1 could be referred to as just
"queue1", and a queue2 could be referred to as just "parent1.queue2".
Additionally, the fair scheduler allows setting a different custom policy for
each queue to allow sharing the queue's resources in any which way the user
wants. A custom policy can be built by extending
<<<org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.SchedulingPolicy>>>.
FifoPolicy, FairSharePolicy (default), and DominantResourceFairnessPolicy are
built-in and can be readily used.
Certain add-ons are not yet supported which existed in the original (MR1) Certain add-ons are not yet supported which existed in the original (MR1)
Fair Scheduler. Among them, is the use of a custom policies governing Fair Scheduler. Among them, is the use of a custom policies governing
@ -201,11 +208,12 @@ Allocation file format
default to 1, and a queue with weight 2 should receive approximately twice default to 1, and a queue with weight 2 should receive approximately twice
as many resources as a queue with the default weight. as many resources as a queue with the default weight.
* schedulingMode: either "fifo" or "fair" depending on the in-queue scheduling * schedulingPolicy: to set the scheduling policy of any queue. The allowed
policy desired. Defaults to "fair". If "fifo", apps with earlier submit values are "fifo"/"fair"/"drf" or any class that extends
times are given preference for containers, but apps submitted later may <<<org.apache.hadoop.yarn.server.resourcemanager.scheduler.fair.SchedulingPolicy>>>.
run concurrently if there is leftover space on the cluster after satisfying Defaults to "fair". If "fifo", apps with earlier submit times are given preference
the earlier app's requests. for containers, but apps submitted later may run concurrently if there is
leftover space on the cluster after satisfying the earlier app's requests.
* aclSubmitApps: a list of users that can submit apps to the queue. A (default) * aclSubmitApps: a list of users that can submit apps to the queue. A (default)
value of "*" means that any users can submit apps. A queue inherits the ACL of value of "*" means that any users can submit apps. A queue inherits the ACL of
@ -236,7 +244,7 @@ Allocation file format
<maxResources>90000 mb</maxResources> <maxResources>90000 mb</maxResources>
<maxRunningApps>50</maxRunningApps> <maxRunningApps>50</maxRunningApps>
<weight>2.0</weight> <weight>2.0</weight>
<schedulingMode>fair</schedulingMode> <schedulingPolicy>fair</schedulingPolicy>
<queue name="sample_sub_queue"> <queue name="sample_sub_queue">
<minResources>5000 mb</minResources> <minResources>5000 mb</minResources>
</queue> </queue>