I installed ubuntu 18.04 LTS and checked a setting for docker (17.06.2-ce) to install at the same time.
I tested by starting the hello-world (sudo docker run hello-world) :
[...] Hello from Docker! This message shows that your installation appears to be working correctly. [...]
I mounted a software raid on the folder named /raid, and make a folder /docker-data in it.
I try to change the root dir of my docker to put it in /raid/docker-data/ by following the few tutorials on the network... in vain.
these solutions don't work either :
/etc/default/docker : I can't find thisDocker Root Dir: /var/snap/docker/common/var-lib-docker
Has anyone managed to do this feat in recent months?
(this is my 3rd installation of ubuntu and I just broke it...)
Apparently on Ubuntu 18.04 LTS, docker 17.06.2-it needs to work with snap, I'm going to dig this way. I will try to return answer later...
I come back to you to give you the solution that allowed me to solve this problem.
cannot perform operation: mount --rbind /var/snap /tmp/snap.rootfs_RRAjdq//var/snap: Permission denied
I know why : https://bugs.launchpad.net/snapcraft/+bug/1620771 :
When /home is a symlink snaps don't work.
When /home is a real directory snaps work, see output below
In my case :
When /raid/snap is a symlink snaps don't work.
When /var/snap is a real directory snaps work.
I deleted docker. I had to reinstall snapcraf (snapd) because I was left on file modifications of it (wrong way)
from there, I stopped the snapd service:
sudo mv /var/snap/ /raid/snap
sudo mount --rbind /raid/snap /var/snap
I started the snapd service.
sudo snap install docker
sudo docker info <= to test
sudo docker run hello-world <= to test
I fixed my mount on fstab:
/raid/snap /var/snap none bind
I restarted my OS : it worked, at least for my case. (I checked all along this file consistency handling to see if the docker files was going well on the raid...)