I have a Docker host that became unreachable for me. The only thing I could get was snapshots of its volumes. I need to extract the docker images from those snapshots.
I created regular volumes from the snapshots, which I was able to attach to a new virtual machine. I now have access to the original host's filesystem.
My first idea was starting a local docker daemon and extract the images using
docker save. This does not work. I tried several things to point my
dockerd to what was
/var/lib/docker on the original machine. I tried copying the files, bind mount and
dockerd -g. The result is always the same: the VM freezes.
After that I tried copying
/var/lib/images/overlay2. This allows my
dockerd to start without freezing the system but
docker image ls does not show any images present.
As far as i can tell, theoretically, it should be possible to mount the docker images using
mount -t overlay. This would rid me of using
docker, but I have no idea how to go about building the mount command.
How can I salvage my docker images from the "raw" filesystem?