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https://issues.apache.org/jira/browse/SLING-7830?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16580985#comment-16580985
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Alexander Saar commented on SLING-7830:
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I see 2 scenarios:
* control the leader in same topology: either via an API to make an implicit
switch to another leader after deployment or force leader during first startup
when a new process with a newer version is deployed (subsequent
startups/deploys would always have newer version, so think this should be ok)
* 2 separate topologies (with 2 independent masters): much harder to control
and not sure if really required. maybe focus should be on first option
initially.
> Defined leader switch
> ---------------------
>
> Key: SLING-7830
> URL: https://issues.apache.org/jira/browse/SLING-7830
> Project: Sling
> Issue Type: Improvement
> Components: Discovery
> Reporter: Carsten Ziegeler
> Priority: Major
>
> The current leader selection is based on startup time and sling id (mainly)
> and is stable across changed in the topology for as long as the leader is up
> and running.
> However there are use cases like blue green deployment where new instances
> with a new version are started and taking over the functionality. However
> with the current discovery setup, the leader would still be one of the
> instances with the old version.
> With a new deployed version, tasks currently bound to the leader should run
> on the new version.
> Therefore the leader needs to switch and stay the leader (until it dies).
> We probably need an additional criteria for the leader selection
> /cc [~egli]
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