Error: failed to start redis service unit redis service not found

Understanding the Redis Service Not Found Error

The error "failed to start redis service unit redis service not found" typically indicates issues with Redis installation, service configuration, or the redis.conf file. Let's focus on potential misconfigurations in the redis.conf file that could cause this error.

Key Areas to Check in redis.conf

1. Port Configuration

   • Look for the port directive
   • Ensure it's set to the default 6379 or your intended port
   • Example: port 6379
   • If you change this, update your service file accordingly

2. Bind Address

   • Check the bind directive
   • For local-only access: bind 127.0.0.1
   • For all interfaces: bind 0.0.0.0
   • Ensure it's not binding to a non-existent IP

3. Unix Socket

   • If using Unix socket, verify unixsocket directive
   • Example: unixsocket /var/run/redis/redis.sock
   • Ensure the directory exists and has proper permissions

4. Working Directory

   • Check dir directive
   • Example: dir /var/lib/redis
   • Ensure this directory exists and Redis has write access

5. Log File

   • Verify logfile directive
   • Example: logfile /var/log/redis/redis-server.log
   • Ensure the directory exists and Redis can write to it

6. Database Configuration

   • Check dbfilename and dir for persistence
   • Example:

     dbfilename dump.rdb
     dir /var/lib/redis
     

   • Ensure these paths exist and are writable

7. Memory Settings

   • Verify maxmemory is set appropriately
   • Example: maxmemory 256mb
   • Ensure it doesn't exceed available system memory

8. User and Permissions

   • If supervised is set, ensure it matches your init system
   • Example for systemd: supervised systemd

Steps to Resolve

1. Open redis.conf:

   sudo nano /etc/redis/redis.conf
   

2. Check and correct the above settings

3. Save changes and exit

4. Ensure proper permissions:

   sudo chown redis:redis /etc/redis/redis.conf
   sudo chmod 640 /etc/redis/redis.conf
   

5. Restart Redis service:

   sudo systemctl restart redis
   

6. Check service status:

   sudo systemctl status redis
   

If the error persists, check system logs for more details:

sudo journalctl -u redis

Remember, any changes to redis.conf require a service restart to take effect. Always backup your configuration file before making changes.