Redis CLI

• redis-cli is the command-line interface for interacting with a Redis server.
• It allows you to send commands, configure settings, and test data operations.
• By default, it connects to:
  • Host: 127.0.0.1 (localhost)
  • Port: 6379 (default Redis port)

Redis CLI Configuration

You can connect with options:

• Specify host & port

docker exec -it redis-server redis-cli -h 127.0.0.1 -p 6379

• With authentication (if Redis has a password)

docker exec -it redis-server redis-cli -a mypassword

• Run a single command without entering interactive mode

docker exec -it redis-server redis-cli PING

Redis redis.conf File

The redis.conf file is the main configuration file for Redis.

• When Redis starts, it reads this file to load settings.
• By default, it’s located in /etc/redis/redis.conf (Linux) or inside the Redis source folder.

Docker container does not include a redis.conf file by default.

1. Create a folder on your host(project): mkdir redis-config

2. Download a redis.conf template: curl -o redis-config/redis.conf https://raw.githubusercontent.com/redis/redis/7.0/redis.conf

3. Use redis.conf in Docker container

   docker stop redis-server
   docker rm redis-server
   
   docker run -d ^
     --name redis-server ^
     -p 6379:6379 ^
     -v "%cd%\redis-config\redis.conf":/usr/local/etc/redis/redis.conf ^
     redis redis-server /usr/local/etc/redis/redis.conf

If no config is given, Redis starts with default settings

Main Sections of redis.conf

Here are the most important settings you’ll encounter in redis.conf:

1. General Settings

   • Daemonize (background mode): daemonize yes

     • yes → Redis runs in the background.
     • no → Redis runs in the foreground (useful for debugging).

   • PID file (process ID storage): pidfile /var/run/redis/redis-server.pid

2. Networking

   • Port Redis listens on port 6379, Default is 6379. You can change it if needed.
   • Bind address: bind 127.0.0.1, Redis will only accept connections from localhost.
   • If you want to allow external access: bind 0.0.0.0. But for security, you must add a password (see below).

3. Security

   • Require password for clients: requirepass myStrongPassword
   • After setting this, every client must authenticate: redis-cli -a myStrongPassword

4. Persistence (Saving Data)

   Redis stores data in memory, but persistence ensures data is saved to disk.

   • RDB snapshots (point-in-time saves):

     save 900 1   # Save if at least 1 key changed in 900 seconds (15 min)
     save 300 10  # Save if at least 10 keys changed in 300 seconds (5 min)
     save 60 10000 # Save if 10000 keys changed in 60 seconds

   • AOF (Append-Only File) logging:

     appendonly yes
     appendfsync everysec

     • Keeps a log of all write operations.
     • everysec → syncs data every second (good balance between performance and safety).

5. Memory Management

   • Maximum memory limit:

     maxmemory 256mb

   • Redis will not use more than 256 MB RAM.

   • Eviction policy (when memory is full):

     maxmemory-policy allkeys-lru

     Options:

     • noeviction → return error when memory full.
     • allkeys-lru → remove least recently used keys.
     • volatile-lru → remove LRU keys with TTL set.

6. Logging

   • Log level:

     loglevel notice

     Options: debug, verbose, notice, warning.

   • Log file path:

     logfile /var/log/redis/redis-server.log

7. Replication (Master/Replica setup)

   Make this Redis a replica of another:

   replicaof 192.168.1.100 6379

   This makes Redis sync data from the given master.