Redis High Availability

Note: This is optional for homelab setups. Single Redis instance is sufficient for most use cases.

When You Need HA

Consider Redis HA if: - Running production workloads - Uptime > 99.9% required - Can't afford to lose queued tasks - Multiple workers across machines

Redis Sentinel (Recommended)

Setup

# docker-compose.yml
version: '3.8'
services:
  redis-master:
    image: redis:7-alpine
    command: redis-server --maxmemory 2gb

  redis-replica:
    image: redis:7-alpine
    command: redis-server --slaveof redis-master 6379

  redis-sentinel-1:
    image: redis:7-alpine
    command: redis-sentinel /etc/redis/sentinel.conf
    volumes:
      - ./sentinel.conf:/etc/redis/sentinel.conf

sentinel.conf:

sentinel monitor mymaster redis-master 6379 2
sentinel down-after-milliseconds mymaster 5000
sentinel parallel-syncs mymaster 1
sentinel failover-timeout mymaster 10000

Application Configuration

# worker-config.yaml
redis_addr: "redis-sentinel-1:26379,redis-sentinel-2:26379"
redis_master_name: "mymaster"

Redis Cluster (Advanced)

For larger deployments with sharding needs.

# Minimum 3 masters + 3 replicas
services:
  redis-1:
    image: redis:7-alpine
    command: redis-server --cluster-enabled yes

  redis-2:
    # ... similar config

Homelab Alternative: Persistence Only

For most homelabs, just enable persistence:

# docker-compose.yml
services:
  redis:
    image: redis:7-alpine
    command: redis-server --appendonly yes
    volumes:
      - redis_data:/data

volumes:
  redis_data:

This ensures tasks survive Redis restarts without full HA complexity.

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Recommendation: Start simple. Add HA only if you experience actual downtime issues.