Is it safe to clean docker/overlay2/

docker docker-compose docker-machine
qichao_he picture qichao_he · Oct 10, 2017 · Viewed 104.5k times · Source

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

BMitch picture BMitch · Oct 10, 2017

Docker uses /var/lib/docker to store your images, containers, and local named volumes. Deleting this can result in data loss and possibly stop the engine from running. The overlay2 subdirectory specifically contains the various filesystem layers for images and containers.

To cleanup unused containers and images, see docker system prune. There are also options to remove volumes and even tagged images, but they aren't enabled by default due to the possibility of data loss.

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