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https://issues.apache.org/jira/browse/YARN-1307?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13801995#comment-13801995
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Bikas Saha commented on YARN-1307:
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To be clear, each app, app attempt, delegation token, secret key are stored
separately in their own znodes. We are not batching multiple of them in the
same znode. Are you suggesting that we batch them in a znode? e.g. all
delegation tokens are stored in a single znode under the delegation token root
znode? For that we will have to take care that the size a data in a single
znode does not exceed ~500KB (ZK is supposed to support upto 1MB).
We already have serialization formats defined for the stuff we store today. So
you can re-use them. For ones that dont exist, I would suggest creating PB
objects. eg. version info.
> Rethink znode structure for RM HA
> ---------------------------------
>
> Key: YARN-1307
> URL: https://issues.apache.org/jira/browse/YARN-1307
> Project: Hadoop YARN
> Issue Type: Sub-task
> Components: resourcemanager
> Reporter: Tsuyoshi OZAWA
> Assignee: Tsuyoshi OZAWA
> Attachments: YARN-1307.1.patch, YARN-1307.2.patch
>
>
> Rethink for znode structure for RM HA is proposed in some JIRAs(YARN-659,
> YARN-1222). The motivation of this JIRA is quoted from Bikas' comment in
> YARN-1222:
> {quote}
> We should move to creating a node hierarchy for apps such that all znodes for
> an app are stored under an app znode instead of the app root znode. This will
> help in removeApplication and also in scaling better on ZK. The earlier code
> was written this way to ensure create/delete happens under a root znode for
> fencing. But given that we have moved to multi-operations globally, this isnt
> required anymore.
> {quote}
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