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https://issues.apache.org/jira/browse/YARN-5677?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Daniel Templeton updated YARN-5677:
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Description:
In trunk, there is no maximum number of retries that I see. It appears the
connection will be retried forever, with the active never figuring out it's no
longer active. In my testing, the active-active state lasted almost 2 hours
with no sign of stopping before I killed it. The solution appears to be to cap
the number of retries or amount of time spent retrying.
This issue is significant because of the asynchronous nature of job submission.
If the active doesn't know it's not active, it will buffer up job submissions
until it finally realizes it has become the standby. Then it will fail all the
job submissions in bulk. In high-volume workflows, that behavior can create
huge mass job failures.
This issue is also important because the node managers will not fail over to
the new active until the old active realizes it's the standby. Workloads
submitted after the old active loses contact with ZK will therefore fail to be
executed regardless of which RM the clients contact.
was:
Both branch-2.8/trunk and branch-2.7 have issues when the active RM loses
contact with the ZK node(s).
In branch-2.7, the RM will retry the connection 1000 times by default.
Attempting to contact a node which cannot be reached is slow, which means the
active can take over an hour to realize it is no longer active. I clocked it
at about an hour and a half in my tests. The solution appears to be to add
some time awareness into the retry loop.
In branch-2.8/trunk, there is no maximum number of retries that I see. It
appears the connection will be retried forever, with the active never figuring
out it's no longer active. In my testing, the active-active state lasted
almost 2 hours with no sign of stopping before I killed it. The solution
appears to be to cap the number of retries or amount of time spent retrying.
This issue is significant because of the asynchronous nature of job submission.
If the active doesn't know it's not active, it will buffer up job submissions
until it finally realizes it has become the standby. Then it will fail all the
job submissions in bulk. In high-volume workflows, that behavior can create
huge mass job failures.
This issue is also important because the node managers will not fail over to
the new active until the old active realizes it's the standby. Workloads
submitted after the old active loses contact with ZK will therefore fail to be
executed regardless of which RM the clients contact.
> RM can be in active-active state for an extended period
> -------------------------------------------------------
>
> Key: YARN-5677
> URL: https://issues.apache.org/jira/browse/YARN-5677
> Project: Hadoop YARN
> Issue Type: Bug
> Components: resourcemanager
> Affects Versions: 3.0.0-alpha1
> Reporter: Daniel Templeton
> Assignee: Daniel Templeton
> Priority: Critical
> Attachments: YARN-5677.001.patch
>
>
> In trunk, there is no maximum number of retries that I see. It appears the
> connection will be retried forever, with the active never figuring out it's
> no longer active. In my testing, the active-active state lasted almost 2
> hours with no sign of stopping before I killed it. The solution appears to
> be to cap the number of retries or amount of time spent retrying.
> This issue is significant because of the asynchronous nature of job
> submission. If the active doesn't know it's not active, it will buffer up
> job submissions until it finally realizes it has become the standby. Then it
> will fail all the job submissions in bulk. In high-volume workflows, that
> behavior can create huge mass job failures.
> This issue is also important because the node managers will not fail over to
> the new active until the old active realizes it's the standby. Workloads
> submitted after the old active loses contact with ZK will therefore fail to
> be executed regardless of which RM the clients contact.
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