As you can see it's one of the simplest approaches: add the old master as a slave ASAP, but flagged. Convert it when back claiming be master
@antirez it's great that the old master comes back as a slave. How do we deal with old sentinels that come back and still think it's master?
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@avibryant Sentinels only act based on INFO reporting fortunately, so the old sentinels will clear the DEMOTE flag ASAP.Thanks. Twitter will use this to make your timeline better. UndoUndo
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@avibryant however with wrong timing, an old sentinel with DEMOTE flag set for a given instance, may turn the real master into a slaveThanks. Twitter will use this to make your timeline better. UndoUndo
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@avibryant for this to happen we need the old master to be reconfigured as a slave, and then fail over the new master again.Thanks. Twitter will use this to make your timeline better. UndoUndo
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@avibryant it is possible to protect from this problem as well if we think it's worth it (probably yes) -
@antirez the case I'm thinking of is: server A with the master goes down, that server has a sentinel configured to monitor the master on A, -
@antirez server A comes back up, its master gets demoted and slaved to B but if you ask the sentinel on A it still thinks the master is on A -
@avibryant in that case Sentinel handles it well, since it asks INFO and sees it's a slave instead to be a master. -
@antirez ok, thanks. It seemed before that redirect-to-master wasn't happening, but I can't reproduce, so maybe I was mistaken. -
@avibryant you are right, I'm able to reproduce that sometimes the role changed is not sensed. Investigating ...
End of conversation
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@avibryant@antirez STONITH —Shoot The Other Node In The HeadThanks. Twitter will use this to make your timeline better. UndoUndo
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