Is it safe to clean docker/overlay2/

Question

I got some docker containers running on AWS EC2, the /var/lib/docker/overlay2 folder grows very fast in disk size.

I'm wondering if it is safe to delete its content? or if docker has some kind of command to free up some disk usage.

---

UPDATE:

I actually tried docker system prune -a already, which reclaimed 0Kb.

Also my /docker/overlay2 disk size is much larger than the output from docker system df

After reading docker documentation and BMitch's answer, I believe it is a stupid idea to touch this folder and I will try other ways to reclaim my disk space.

Answer 1

I had this issue... It was the log that was huge. Logs are here :

/var/lib/docker/containers/<container id>/<container id>-json.log

You can manage this in the run command line or in the compose file. See there : Configure logging drivers

I personally added these 3 lines to my docker-compose.yml file :

my_container:
  logging:
    options:
      max-size: 10m