[jira] [Commented] (YARN-3212) RMNode State Transition Update with DECOMMISSIONING state

["Wangda Tan (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/YARN-3212?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14741738#comment-14741738 ] 

Wangda Tan commented on YARN-3212:
----------------------------------

Hi [~djp],

Thanks for working on this JIRA, just took a look at it:

*1) ResourceTrackerService:*
Question:
1. Why shutdown a "decommissioning" NM if it is doing heartbeat. Should we allow it continue heartbeat, since RM needs to know about container finished / killed information.

*2) RMNodeImpl:*
Question:
2. Do we have timeout of graceful decomission? Which will update a node to "DECOMMISSIONED" after the timeout.
3. If I understand correct, decommissioning is another running state, except:
- We cannot allocate any new containers to it.

Comments:
- If answer to question #2 is no, I suggest to rename RMNodeEventType.DECOMISSION_WITH_TIMEOUT to GRACEFUL_DECOMISSION, since it doesn't have a "real" timeout.
- Why this is need?
{code}
      .addTransition(NodeState.DECOMMISSIONING, NodeState.DECOMMISSIONING,
          RMNodeEventType.DECOMMISSION_WITH_TIMEOUT,
          new DecommissioningNodeTransition(NodeState.DECOMMISSIONING))
{code}
Should we simply ignore the DECOMMISSION_WITH_TIMEOUT event?
- Is there specific considerations that transfer UNHEALTHY to DECOMISSIONED when DECOMMISSION_WITH_TIMEOUT received? Is it better to transfer it to DECOMISSIONING since it has some containers running on it?
- One suggestion of how to handle node update to scheduler: I think you can add a field "isDecomissioning" to NodeUpdateSchedulerEvent, and scheduler can do all updates except allocate container.

> RMNode State Transition Update with DECOMMISSIONING state
> ---------------------------------------------------------
>
>                 Key: YARN-3212
>                 URL: https://issues.apache.org/jira/browse/YARN-3212
>             Project: Hadoop YARN
>          Issue Type: Sub-task
>          Components: resourcemanager
>            Reporter: Junping Du
>            Assignee: Junping Du
>         Attachments: RMNodeImpl - new.png, YARN-3212-v1.patch, YARN-3212-v2.patch, YARN-3212-v3.patch, YARN-3212-v4.1.patch, YARN-3212-v4.patch, YARN-3212-v5.1.patch, YARN-3212-v5.patch
>
>
> As proposed in YARN-914, a new state of “DECOMMISSIONING” will be added and can transition from “running” state triggered by a new event - “decommissioning”. 
> This new state can be transit to state of “decommissioned” when Resource_Update if no running apps on this NM or NM reconnect after restart. Or it received DECOMMISSIONED event (after timeout from CLI).
> In addition, it can back to “running” if user decides to cancel previous decommission by calling recommission on the same node. The reaction to other events is similar to RUNNING state.



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