Subscribe to switch master message is necessary about redis-sentinel HOT 4 OPEN

@isaiah I forgot the reason, but you're right, I should add it back.

from redis-sentinel.

I just saw this with some testing. I added an action to my rack app, to test writability with a simple SET and GET. Then I spammed that action while a background process was sending "SENTINEL failover mymaster" to a sentinel every 20 seconds. Eventually, the SET operation fails.

It occurs to me that I could have the resilience I want without +switch-master event monitoring, if the redis-sentinel gem responded to failures as follows:

• Issue the INFO command.
• If it succeeds, and the output indicates that the instance is not master, rediscover current master and retry.

Rediscovery would probably enjoy a configurable delay.

What do you think?

from redis-sentinel.

Hi, I just had it happen with a resque-only redis in a production environment with down-after-milliseconds that seems to have been set a bit too low, as sentinel failed it over randomly after 3 days of running with no problems.
This is a pretty serious issues - after the switch, all I could do was restart every process using redis in the cluster (which is most of them) and try to rescue missed jobs.

Is there any plan to track sentinel promotions again?

from redis-sentinel.

@isaiah @sheldonh @reist sorry for the late commit, finally I added "subscribe +switch-master" back again, please let me know if it works for you.

from redis-sentinel.