Redis High Availability with Sentinel
Build a self-healing 3-node Redis cluster: replication plus Sentinel for automatic failover — no proxy, no virtual IP. Step-by-step on Ubuntu, ending with a hard-kill failover test.
Overview & Architecture
Redis ships with replication and a dedicated high-availability companion — Sentinel — but they ar...
Environment & Prerequisites
Servers You need three Linux servers (Ubuntu 24.04 LTS or 26.04 — Redis 8 and the redis-sentinel...
Install Redis & Configure Replication
We install the same two packages on all three nodes, then point the two replicas at the primary. ...
Sentinel — Automatic Failover Configuration
Replication gives us copies. Sentinel is what turns those copies into high availability — it watc...
Connecting Applications
This is the part that makes Sentinel different from a database-behind-a-proxy setup: the client d...
Failover & Recovery Testing
Now the payoff: we kill the primary and watch the cluster heal itself with no human intervention....
Production Hardening & Troubleshooting
The build above is functionally HA. Before production, tighten these. Persistence — survive a ful...