Tao Yang created YARN-8804:
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Summary: resourceLimits may be wrongly calculated when leaf-queue
is blocked in cluster with 3+ level queues
Key: YARN-8804
URL: https://issues.apache.org/jira/browse/YARN-8804
Project: Hadoop YARN
Issue Type: Bug
Components: capacityscheduler
Affects Versions: 3.2.0
Reporter: Tao Yang
Assignee: Tao Yang
This problem is due to YARN-4280, parent queue will deduct child queue's
headroom when the child queue reached its resource limit and the skipped type
is QUEUE_LIMIT, the resource limits of deepest parent queue will be correctly
calculated, but for non-deepest parent queue, its headroom may be much more
than the sum of reached-limit child queues' headroom, so that the resource
limit of non-deepest parent may be much less than its true value and block the
allocation for later queues.
To reproduce this problem with UT:
(1) Cluster has two nodes whose node resource both are <10GB, 10core> and
3-level queues as below, among them max-capacity of "c1" is 10 and others are
all 100, so that max-capacity of queue "c1" is <2GB, 2core>
Root
/ | \
a b c
10 20 70
| \
c1 c2
10(max=10) 90
(2) Submit app1 to queue "c1" and launch am1(resource=<1GB, 1 core>) on nm1
(3) Submit app2 to queue "b" and launch am2(resource=<1GB, 1 core>) on nm1
(4) app1 and app2 both ask one <2GB, 1core> containers.
(5) nm1 do 1 heartbeat
Now queue "c" has lower capacity percentage than queue "b", the allocation
sequence will be "a" -> "c" -> "b",
queue "c1" has reached queue limit so that requests of app1 should be pending,
headroom of queue "c1" is <1GB, 1core> (=max-capacity - used),
headroom of queue "c" is <18GB, 18core> (=max-capacity - used),
after allocation for queue "c", resource limit of queue "b" will be wrongly
calculated as <2GB, 2core>,
headroom of queue "b" will be <1GB, 1core> (=resource-limit - used)
so that scheduler won't allocate one container for app2 on nm1
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