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https://issues.apache.org/jira/browse/HBASE-7386?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13869915#comment-13869915
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Samir Ahmic commented on HBASE-7386:
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Thanks for review [~nkeywal].
I agree about 'PROCESS_STATE_UNKNOWN', i checked it in supervisor source code
and it is look like that is used for actions if supervisor is unable to
determine state of process. I will remove it from event listener since it can
cause issues.
I was planing to make mail notification optional even to create separate event
listener that will handle email notifications. '/bin/mail' is most simple
solution and following that example folks could develop there own solution.
What do you think how this should be handled ?
bq. Do we have to use python?
According to documentation: "Event listener can be written in any language
supported by the platform you’re using to run supervisor. There is special
library support for Python in the form of a supervisor.childutils module, which
makes creating event listeners in Python slightly easier than in other
languages." Any suggestions what should we use instead of python ? Java ?
When we complete this work it should be documented probably under "15. Apache
HBase Operational Management" ?
> Investigate providing some supervisor support for znode deletion
> ----------------------------------------------------------------
>
> Key: HBASE-7386
> URL: https://issues.apache.org/jira/browse/HBASE-7386
> Project: HBase
> Issue Type: Task
> Components: master, regionserver, scripts
> Reporter: Gregory Chanan
> Assignee: stack
> Priority: Blocker
> Attachments: HBASE-7386-bin-v2.patch, HBASE-7386-bin.patch,
> HBASE-7386-conf-v2.patch, HBASE-7386-conf.patch, HBASE-7386-src.patch,
> HBASE-7386-v0.patch, supervisordconfigs-v0.patch
>
>
> There a couple of JIRAs for deleting the znode on a process failure:
> HBASE-5844 (RS)
> HBASE-5926 (Master)
> which are pretty neat; on process failure, they delete the znode of the
> underlying process so HBase can recover faster.
> These JIRAs were implemented via the startup scripts; i.e. the script hangs
> around and waits for the process to exit, then deletes the znode.
> There are a few problems associated with this approach, as listed in the
> below JIRAs:
> 1) Hides startup output in script
> https://issues.apache.org/jira/browse/HBASE-5844?focusedCommentId=13463401&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13463401
> 2) two hbase processes listed per launched daemon
> https://issues.apache.org/jira/browse/HBASE-5844?focusedCommentId=13463409&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13463409
> 3) Not run by a real supervisor
> https://issues.apache.org/jira/browse/HBASE-5844?focusedCommentId=13463409&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13463409
> 4) Weird output after kill -9 actual process in standalone mode
> https://issues.apache.org/jira/browse/HBASE-5926?focusedCommentId=13506801&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13506801
> 5) Can kill existing RS if called again
> https://issues.apache.org/jira/browse/HBASE-5844?focusedCommentId=13463401&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13463401
> 6) Hides stdout/stderr[6]
> https://issues.apache.org/jira/browse/HBASE-5844?focusedCommentId=13506832&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13506832
> I suspect running in via something like supervisor.d can solve these issues
> if we provide the right support.
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