How to Set Up Redis Sentinel for High Availability

How to Set Up Redis Sentinel for High Availability

Redis Sentinel provides automatic failover and monitoring so your Breeze applications maintain Redis availability even when a node fails.

Architecture Overview

• 1 Master - handles all writes
• 2 Replicas - synchronize from master, serve reads
• 3 Sentinels - monitor and trigger failover (use odd number for quorum)

Configure the Master

On your primary Breeze, ensure Redis is bound to its private IP:

bind 10.0.0.1 127.0.0.1
port 6379
requirepass YourRedisPassword
masterauth YourRedisPassword

Configure Replicas

On each replica Breeze, add to redis.conf:

replicaof 10.0.0.1 6379
masterauth YourRedisPassword
requirepass YourRedisPassword

Configure Sentinel

Create /etc/redis/sentinel.conf on three servers:

port 26379
sentinel monitor mymaster 10.0.0.1 6379 2
sentinel auth-pass mymaster YourRedisPassword
sentinel down-after-milliseconds mymaster 5000
sentinel failover-timeout mymaster 10000
sentinel parallel-syncs mymaster 1

Start Sentinels

redis-sentinel /etc/redis/sentinel.conf --daemonize yes

Verify Failover

redis-cli -p 26379 SENTINEL master mymaster
redis-cli -p 26379 SENTINEL replicas mymaster

If the master fails, Sentinel automatically promotes a replica, keeping your Breeze applications connected.