Docker Compose with Redis

Overview

A Docker Compose setup for Redis as a caching layer, session store, or message broker. Includes persistence options (RDB snapshots and AOF logging), password authentication, memory management, and an optional web UI.

Configuration

# docker-compose.yml

services:
  redis:
    image: redis:7-alpine              # Latest Redis 7 on Alpine
    container_name: app-redis
    restart: unless-stopped

    ports:
      - "6379:6379"                    # Default Redis port

    volumes:
      - redis_data:/data               # Persist data between restarts

    # Redis configuration via command flags
    command: >
      redis-server
      --requirepass ${REDIS_PASSWORD:-redispass}
      --maxmemory 256mb
      --maxmemory-policy allkeys-lru
      --appendonly yes
      --appendfsync everysec
      --save 900 1
      --save 300 10
      --save 60 10000
      --tcp-backlog 511
      --timeout 300
      --tcp-keepalive 60
      --loglevel notice

    healthcheck:
      test: ["CMD", "redis-cli", "-a", "${REDIS_PASSWORD:-redispass}", "ping"]
      interval: 10s
      timeout: 5s
      retries: 5
      start_period: 10s

    # Limit container resources
    deploy:
      resources:
        limits:
          memory: 512M                 # Hard memory ceiling
          cpus: '0.5'

  redis-commander:
    image: rediscommander/redis-commander:latest
    container_name: app-redis-commander
    restart: unless-stopped
    profiles:
      - tools                          # Only starts with --profile tools

    environment:
      REDIS_HOSTS: "local:redis:6379:0:${REDIS_PASSWORD:-redispass}"
      HTTP_USER: admin                 # Basic auth for web UI
      HTTP_PASSWORD: ${REDIS_UI_PASSWORD:-admin}

    ports:
      - "8081:8081"                    # Web UI port

    depends_on:
      redis:
        condition: service_healthy

volumes:
  redis_data:
    driver: local

Key Options Explained

• --requirepass — Enables password authentication. Always set this, even in development, to build good habits.
• --maxmemory 256mb — Caps Redis memory usage. Without this, Redis will use all available memory and potentially get OOM-killed.
• --maxmemory-policy allkeys-lru — When memory limit is reached, evict the least recently used keys. Other options: volatile-lru (only keys with TTL), noeviction (return errors).
• --appendonly yes — Enables AOF (Append Only File) for durability. Every write is logged so data survives restarts.
• --appendfsync everysec — Flushes AOF to disk every second. Balances durability and performance (at most 1 second of data loss).
• --save 900 1 — Creates an RDB snapshot if at least 1 key changed in 900 seconds. Multiple save rules provide tiered snapshotting.
• --timeout 300 — Closes idle client connections after 300 seconds to free up resources.

Common Modifications

• Disable persistence for pure cache: Remove --appendonly and --save flags. Add --save "" to explicitly disable RDB snapshots.
• Redis Cluster: Use multiple Redis instances with redis:7-alpine and cluster configuration for horizontal scaling.
• Custom config file: Mount with - ./redis.conf:/usr/local/etc/redis/redis.conf and change command to redis-server /usr/local/etc/redis/redis.conf.
• Sentinel for HA: Add Redis Sentinel containers to provide automatic failover in production-like environments.
• Key expiration defaults: Add --default-ttl 3600 or set TTLs in your application code to prevent unbounded cache growth.