Guangya Liu created MESOS-6317:
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Summary: Race in master update slave.
Key: MESOS-6317
URL: https://issues.apache.org/jira/browse/MESOS-6317
Project: Mesos
Issue Type: Bug
Reporter: Guangya Liu
Assignee: Guangya Liu
Currently, when {{updateSlave}} in master, it will first rescind offers and
then updateSlave in allocator, but there is a race for this, there might be a
batch allocation inserted bwteen the two. In this case, the order will be
rescind offer -> batch allocation -> update slave. This order will cause some
issues when the oversubscribed resources was decreased.
Suppose the oversubscribed resources was decreased from 2 to 1, then after
rescind offer finished, the batch allocation will allocate the old 2
oversubscribed resources again, then update slave will update the total
oversubscribed resources to 1. This will cause the agent host have some time
overcommitted due to the tasks can still use 2 oversubscribed resources but not
1 oversubscribed resources, once the tasks using the 2 oversubscribed resources
finished, everything goes back.
So here we should adjust the order of rescind offer and updateSlave in master
to avoid resource overcommit.
If we update slave first then rescind offer, the order will be update slave ->
batch allocation -> rescind offer, this order will have no problem when
descreasing resources. Suppose the oversubscribed resources was decreased from
2 to 1, then update slave will update total oversubscribed resources to 1
directly, then the batch allocation will not allocate any oversubscribed
resources since there are more allocated than total oversubscribed resources,
then rescind offer will rescind all offers using oversubscribed resources. This
will not lead the agent host to be overcommitted.
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