Delete docker overlay2 and free up space on your Linux server

Warning: strong language ahead, needed to vent.

So this is going to be a short one, basically I was having issues with a server filling up with docker/overlay2 garbage and it was frustrating me way too much.

Running df -h showed:

Filesystem      Size  Used Avail Use% Mounted on
udev            982M     0  982M   0% /dev
tmpfs           199M  824K  199M   1% /run
/dev/vda1        18G   18G  457M  98% /
tmpfs           995M   16K  995M   1% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           995M     0  995M   0% /sys/fs/cgroup
/dev/vda15      105M  3.6M  101M   4% /boot/efi
tmpfs           199M     0  199M   0% /run/user/0
overlay          18G   18G  457M  98% /var/lib/docker/overlay2/8c1fcc6b0091c980e0bcf6d85f77ef94aa03ce59d2d5eba1

Yeah it's a smol machine and I was mainly running docker for batch jobs so I didn't wanna persist anything which left me wondering as to why in hell the stuff was just adding up and adding up... Especially that docker/overlay2 stuff seemed like a persistent mother in law, just getting bigger and bigger!

Following some internet wisdom I found out a lot people saying just run "docker system prune -af". Which actually does jack shit. I found a solution for non pruned af people like me.

So in case you have the same issue and don't store ANY DATA in docker containers or docker volumes do this:

systemctl stop docker
rm -rf /var/lib/docker/
systemctl start docker

and nuke that shit to oblivion! Enjoy the free space. I am too frustrated right now to explain why this works but whatever, closing the issue lmao.

Filesystem      Size  Used Avail Use% Mounted on
udev            982M     0  982M   0% /dev
tmpfs           199M  748K  199M   1% /run
/dev/vda1        18G  7.5G   11G  42% /
tmpfs           995M   16K  995M   1% /dev/shm
tmpfs           5.0M     0  5.0M   0% /run/lock
tmpfs           995M     0  995M   0% /sys/fs/cgroup
/dev/vda15      105M  3.6M  101M   4% /boot/efi
tmpfs           199M     0  199M   0% /run/user/0

There is also a great way to reduce the log size for docker containers but that's easy to figure out and should be done during the initial installation of docker.

What BOGGLES the mind is that these are not sane defaults in a standard docker installation. Now throw Kubernetes in the mix and you'll be employed for the next 50 years...