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Say I have a Redis setup of 3 servers and I have redis-sentinel configured to require a quorum of 2 sentinels to initiate a failover. If 2 of my servers die and I only have 1 remaining, is there a way that I can manually sanction that failover to happen even though I do not have a quorum?

I've seen that using SLAVEOF NO ONE should help in certain cases (would this be one of them?) but I couldn't get that to work. Maybe I didn't have the right authentication or I wasn't running it in the right place.

Brady Dowling
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  • Does it help to force a failover by executing `SENTINEL failover `? It will not "asking for agreement to other Sentinels" as in https://redis.io/topics/sentinel. – whatacold May 12 '19 at 04:25

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When 2/3 servers are down, the sentinels can't vote for odown event since the quorum is set to 2.

You need to update the quorum to 1 in the case where 2/3 nodes can go down and you can update the remaining node as the master

Atish
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  • Hmm, so to manually sanction a failover I could just log into the 1 remaining sentinel and change the quorum on there to be 1 so it will assert itself as the master? I'm guessing that would cause issues when the other 2 servers come back online but maybe it's a short term solution. – Brady Dowling Oct 13 '18 at 15:58
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    To clarify, there is no way to manually assert that one server should assert itself as master. This must be done via sentinel and hacking configurations there. – Brady Dowling Feb 01 '19 at 13:58