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YARN-4827. Document configuration of ReservationSystem for FairScheduler. (Yufei Gu via Subru).

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Subru Krishnan 2017-10-25 15:07:50 -07:00
parent 7da15eac7a
commit 3fae675383
3 changed files with 25 additions and 4 deletions
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3
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/reservation/CapacityOverTimePolicy.java
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@ -56,9 +56,6 @@ public class CapacityOverTimePolicy extends NoOverCommitPolicy {
private float maxInst;
private float maxAvg;
// For now this is CapacityScheduler specific, but given a hierarchy in the
// configuration structure of the schedulers (e.g., SchedulerConfiguration)
// it should be easy to remove this limitation
@Override
public void init(String reservationQueuePath,
ReservationSchedulerConfiguration conf) {

24
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/FairScheduler.md
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@ -109,6 +109,8 @@ The allocation file must be in XML format. The format contains five types of ele
* **allowPreemptionFrom**: determines whether the scheduler is allowed to preempt resources from the queue. The default is true. If a queue has this property set to false, this property will apply recursively to all child queues.
* **reservation**: indicates to the `ReservationSystem` that the queue's resources is available for users to reserve. This only applies for leaf queues. A leaf queue is not reservable if this property isn't configured.
* **User elements**: which represent settings governing the behavior of individual users. They can contain a single property: maxRunningApps, a limit on the number of running apps for a particular user.
* **A userMaxAppsDefault element**: which sets the default running app limit for any users whose limit is not otherwise specified.
@ -127,6 +129,12 @@ The allocation file must be in XML format. The format contains five types of ele
* **A defaultQueueSchedulingPolicy element**: which sets the default scheduling policy for queues; overridden by the schedulingPolicy element in each queue if specified. Defaults to "fair".
* **A reservation-agent element**: which sets the class name of the implementation of the `ReservationAgent`, which attempts to place the user's reservation request in the `Plan`. The default value is `org.apache.hadoop.yarn.server.resourcemanager.reservation.planning.AlignedPlannerWithGreedy`.
* **A reservation-policy element**: which sets the class name of the implementation of the `SharingPolicy`, which validates if the new reservation doesn't violate any invariants. The default value is `org.apache.hadoop.yarn.server.resourcemanager.reservation.CapacityOverTimePolicy`.
* **A reservation-planner element**: which sets the class name of the implementation of the `Planner`, which is invoked if the `Plan` capacity fall below (due to scheduled maintenance or node failuers) the user reserved resources. The default value is `org.apache.hadoop.yarn.server.resourcemanager.reservation.planning.SimpleCapacityReplanner`, which scans the `Plan` and greedily removes reservations in reversed order of acceptance (LIFO) till the reserved resources are within the `Plan` capacity.
* **A queuePlacementPolicy element**: which contains a list of rule elements that tell the scheduler how to place incoming apps into queues. Rules are applied in the order that they are listed. Rules may take arguments. All rules accept the "create" argument, which indicates whether the rule can create a new queue. "Create" defaults to true; if set to false and the rule would place the app in a queue that is not configured in the allocations file, we continue on to the next rule. The last rule must be one that can never issue a continue. Valid rules are:
* **specified**: the app is placed into the queue it requested. If the app requested no queue, i.e. it specified "default", we continue. If the app requested a queue name starting or ending with period, i.e. names like ".q1" or "q1." will be rejected.
@ -159,6 +167,9 @@ The allocation file must be in XML format. The format contains five types of ele
<aclSubmitApps>charlie</aclSubmitApps>
<minResources>5000 mb,0vcores</minResources>
</queue>
<queue name="sample_reservable_queue">
<reservation></reservation>
</queue>
</queue>
<queueMaxAMShareDefault>0.5</queueMaxAMShareDefault>
@ -201,6 +212,19 @@ The root queue's ACLs are "\*" by default which, because ACLs are passed down, m
Reservation Access Control Lists (ACLs) allow administrators to control who may take reservation actions on particular queues. They are configured with the aclAdministerReservations, aclListReservations, and the aclSubmitReservations properties, which can be set per queue. Currently the supported administrative actions are updating and deleting reservations. An administrator may also submit and list *all* reservations on the queue. These properties take values in a format like "user1,user2 group1,group2" or " group1,group2". Actions on a queue are permitted if the user/group is a member of the reservation ACL. Note that any user can update, delete, or list their own reservations. If reservation ACLs are enabled but not defined, everyone will have access.
### Configuring `ReservationSystem`
The Fair Scheduler supports the **ReservationSystem** which allows users to reserve resources ahead of time. The application can request reserved resources at runtime by specifying the `reservationId` during submission. The following configuration parameters can be configured in yarn-site.xml for `ReservationSystem`.
| Property | Description |
|:---- |:---- |
| `yarn.resourcemanager.reservation-system.enable` | *Mandatory* parameter: to enable the `ReservationSystem` in the **ResourceManager**. Boolean value expected. The default value is *false*, i.e. `ReservationSystem` is not enabled by default. |
| `yarn.resourcemanager.reservation-system.class` | *Optional* parameter: the class name of the `ReservationSystem`. The default value is picked based on the configured Scheduler, i.e. if `FairScheduler` is configured, then it is `FairReservationSystem`. |
| `yarn.resourcemanager.reservation-system.plan.follower` | *Optional* parameter: the class name of the `PlanFollower` that runs on a timer, and synchronizes the `FairScheduler` with the `Plan` and vice versa. The default value is picked based on the configured Scheduler, i.e. if `FairScheduler` is configured, then it is `FairSchedulerPlanFollower`. |
| `yarn.resourcemanager.reservation-system.planfollower.time-step` | *Optional* parameter: the frequency in milliseconds of the `PlanFollower` timer. Long value expected. The default value is *1000*. |
The `ReservationSystem` is integrated with the Fair Scheduler queue hierarchy and can be configured for and only for leaf queues. The detailed instructions are in section `Allocation file format`.
##Administration
The fair scheduler provides support for administration at runtime through a few mechanisms:

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hadoop-yarn-project/hadoop-yarn/hadoop-yarn-site/src/site/markdown/ReservationSystem.md
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@ -60,4 +60,4 @@ With reference to the figure above, a typical reservation proceeds as follows:
Configuring the Reservation System
----------------------------------
Configuring the `ReservationSystem` is simple. Currently we have added support for *reservations* in both `CapacityScheduler` and `FairScheduler`. You can mark any **leaf queue** in the **capacity-scheduler.xml** or **fair-scheduler.xml** as available for "reservations" (see [CapacityScheduler](./CapacityScheduler.html#Configuring_ReservationSystem_with_CapacityScheduler) and the [FairScheduler](./FairScheduler.html) for details). Then the capacity/fair share within that queue can be used for making reservations. Jobs can still be submitted to the *reservable queue* without a reservation, in which case they will be run in best-effort mode in whatever capacity is left over by the jobs running within active reservations.
Configuring the `ReservationSystem` is simple. Currently we have added support for *reservations* in both `CapacityScheduler` and `FairScheduler`. You can mark any **leaf queue** in the **capacity-scheduler.xml** or **fair-scheduler.xml** as available for "reservations" (see [CapacityScheduler](./CapacityScheduler.html#Configuring_ReservationSystem_with_CapacityScheduler) and the [FairScheduler](./FairScheduler.html#Configuring_ReservationSystem) for details). Then the capacity/fair share within that queue can be used for making reservations. Jobs can still be submitted to the *reservable queue* without a reservation, in which case they will be run in best-effort mode in whatever capacity is left over by the jobs running within active reservations.