サーバーのOSのバージョンアップを行なった際、
手動でRedis Sentinelのフェイルオーバーを行なった際のメモ

master nodeが落ちたことをSentinelが検知するまでの時間を短くするため、手動でフェイルオーバーを行ったほうがいい、ということで...

公式ドキュメントで手動のフェイルオーバーについて記載してある箇所

SENTINEL failover <master name> Force a failover as if the master was not reachable, and without asking for agreement
to other Sentinels (however a new version of the configuration will be published so that the other Sentinels will update their configurations).

コマンド

こんな感じで(dockerで運用しています)

docker exec -it docker_redis-sentinel1_1 bash
redis-cli -p 26379
SENTINEL failover mymaster

Redis Nodeのフェイルオーバー先の重み付け

http://download.redis.io/redis-stable/redis.conf

# The slave priority is an integer number published by Redis in the INFO output.
# It is used by Redis Sentinel in order to select a slave to promote into a
# master if the master is no longer working correctly.
#
# A slave with a low priority number is considered better for promotion, so
# for instance if there are three slaves with priority 10, 100, 25 Sentinel will
# pick the one with priority 10, that is the lowest.
#
# However a special priority of 0 marks the slave as not able to perform the
# role of master, so a slave with priority of 0 will never be selected by
# Redis Sentinel for promotion.
#
# By default the priority is 100.
slave-priority 100

slave-priorityを100より小さい値を設定して優先度を変える