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https://issues.apache.org/jira/browse/HDFS-11699?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16372240#comment-16372240
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Anu Engineer commented on HDFS-11699:
-------------------------------------

[~nandakumar131] Thanks for the comments. Most of the comments make sense and I 
have addressed all them in the v3 patch.

However, we need to check both {{isClosed}} and {{ShouldClose}} functions 
separately. Here is why:
 # {{isClosed}} checks if the container is in a closed state. if so, there is 
no point in sending a close command to a data node. However, SCM might have 
sent a command to a DN, but the DN rebooted before the close happened, or it is 
taking too long to close the container. We should let the closer know about it. 
That is, both {{ContainerCloser}} and {{Datanode}} is assumed to be idempotent.
 # {{ShouldClose}}, unfortunately, can be executed once and only once, from the 
{{Open}} state SCM state machine will transition to {{Closing}}. If we reissue 
a close to the state machine, it is going to throw, hence we cannot just write 
the code as proposed by you in the comment.

> Ozone:SCM: Add support for close containers in SCM
> --------------------------------------------------
>
>                 Key: HDFS-11699
>                 URL: https://issues.apache.org/jira/browse/HDFS-11699
>             Project: Hadoop HDFS
>          Issue Type: Sub-task
>          Components: ozone
>    Affects Versions: HDFS-7240
>            Reporter: Anu Engineer
>            Assignee: Anu Engineer
>            Priority: Major
>         Attachments: HDFS-11699-HDFS-7240.001.patch, 
> HDFS-11699-HDFS-7240.002.patch, HDFS-11699-HDFS-7240.003.patch
>
>
> Add support for closed containers in SCM. When a container is closed, SCM 
> needs to make a set of decisions like which pool and which machines are 
> expected to have this container. SCM also needs to issue a copyContainer 
> command to the target datanodes so that these nodes can replicate data from 
> the original locations.



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