Internal working of Sentinel

This post is based on Redis 4.0.6. Main source of Sentinel is sentinel.c. When a Redis process is run in sentinel mode, sentinelTimer() is called. Inside it, all Sentinel's logic flows. The way to recognize the other Sentinel At initial Sentinel config, there is no info for the other Sentinels. There are only options for …

Important Sentinel options

At the previous post, I wrote about setting up Sentinel. This post explains some important options for a production system. The following is a sample Sentinel config. (based on Redis 4.0.x) You can check full documentation here. sentinel monitor format : sentinel monitor <master-name> <ip> <redis-port> <quorum> master-name : master alias which is used as …

Managing Redis replication with sentinel

Setting up Redis replication is simple. But to support high availability, we need to set up sentinel. Sentinel's main functions are as follows. To monitor master and slave state If a master is down, sentinel promotes a new master among slaves (automatic fail over) If the old master runs again, sentinel changes it's role as …