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https://issues.apache.org/jira/browse/YARN-7117?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16186821#comment-16186821
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Suma Shivaprasad commented on YARN-7117:
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Thanks for your feedback [~jlowe] the syntax would be more concise and easier
to read if the queue could be specified as a sub-path that can optionally
include the parent queue. For example, rather than
u:user1:queue1(parent-queue=marketing) the syntax could be simplified to:
u:user1:marketing.queue1.
{quote} Agree .The current CS code has a bug in that it allows "." in the queue
names. Do you think we should fix this for 3.0? {quote}
I'm not really familiar with queue mappings, but I'm assuming the order they
are specified is significant to deterministically resolve cases where more than
one specified rule would apply to a user. If so then the example is confusing
since it looks like the u:user2:%primary_group(parent-queue=finance) rule will
always be eclipsed by the preceding u:%user:%user(parent=engineering) rule.
{quote} Good catch. The example needs to be fixed {quote}
IMHO if the admin wants to configure guarantees for auto-created queues then we
should not assume that they're going to be OK with auto-created queues that do
not meet those specifications. Otherwise I'd assume the admin would forgo
guaranteed capacities on the auto queues and just have them carve up the parent
queue proportionally.
{quote} Thats a good point. We could have a configuration that allows admins to
have parent queues which allow creation of auto queues with guaranteed
resources and fail submissions when parent doesnt have room. By default this
could allow best effort queues as in current design and could be controlled by
admins when they configure the parent queue.
The document implies that there's SLAs with guaranteed capacity auto-queues,
but that's clearly not the case. In the example, it's true that the
applications submitted to q4 and q5 eventually ran with guaranteed capacities.
However they waited an unbounded amount of time to start running which means we
cannot always hit SLAs. Users in q1/q2/q3 can collectively deny apps in q4/q5
ever running, for example.
{quote} This should be addressed by the above configurable policy. SLA
guarantees are better with the admin able to configure parent queues with
guaranteed capacities for auto created leaf queues {quote}
For the alternative approach where all of the queues are "best effort" we don't
have to always have the max-am-resource at 0%. We could specify the max-am as a
percent of the max cap for those queues or a separate config specific to them,
or whatever. Or we could have the queues auto-distribute the capacities of the
parent as new queues are added. In other words the auto-queue capacity is
1/(num auto queues) of the parent and the max-capacity is always 100%.
Preemption can be used to keep the queues fair if one user tries to dominate
over the others, but capacities of underutilized queues can be leveraged by
others.
{quote} This could be done though it might be a backward in compatible change.
{quote}
If a user has ACLs to the parent queue then I believe they have those ACLs to
the entire hierarchy of that queue. That means if the parent queue says they
can submit then they'll be able to submit to any auto-queue underneath that
parent. We'll either need a new ACL for auto-queue creation separate from app
submission or change the semantics of ACL inheritance for auto-queues. Probably
the former makes more sense and would be more intuitive since admins will be
used to the inheritance features of today's queue ACLs and allow admins to
configure parent-queue-privileged users that can get admin-like access to all
the auto-queues of a parent queue but aren't fully admin users across all
queues.
{quote} Good point. Having separate ACLs for auto-creation would be better
{quote}
I don't know if it's critical to show auto-queues as a different color, but I
think it would be important to be able to determine somehow via the UI that the
queue was auto-created so the admin doesn't wonder why they can't find the
queue in the static queue configs. This might be as simple as a "Auto-Queue:
true/false" line in the queue details box in the UI.
{quote } Agree {quote}
> Capacity Scheduler: Support Auto Creation of Leaf Queues While Doing Queue
> Mapping
> ----------------------------------------------------------------------------------
>
> Key: YARN-7117
> URL: https://issues.apache.org/jira/browse/YARN-7117
> Project: Hadoop YARN
> Issue Type: New Feature
> Components: capacity scheduler
> Reporter: Wangda Tan
> Assignee: Wangda Tan
> Attachments:
> YARN-7117.Capacity.Scheduler.Support.Auto.Creation.Of.Leaf.Queue.pdf
>
>
> Currently Capacity Scheduler doesn't support auto creation of queues when
> doing queue mapping. We saw more and more use cases which has complex queue
> mapping policies configured to handle application to queues mapping.
> The most common use case of CapacityScheduler queue mapping is to create one
> queue for each user/group. However update {{capacity-scheduler.xml}} and
> {{RMAdmin:refreshQueues}} needs to be done when new user/group onboard. One
> of the option to solve the problem is automatically create queues when new
> user/group arrives.
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