Given that this is also the place to store raw disk images which are
very much bootable with qemu/kvm it sounds like a misnomer to call the
directory "container". Hence, let's change this sooner rather than
later, and use the generic name, in particular since we otherwise try to
use the generic "machine" preferably over the more specific "container"
or "vm".
After all, nspawn can now dissect MBR partition levels, too, hence
".gpt" appears a misnomer. Moreover, the the .raw suffix for these files
is already pretty popular (the Fedora disk images use it for example),
hence sounds like an OK scheme to adopt.
Given the write patterns on disk images, we better should turn COW off
for them. In particular as the file systems used inside the disk images
should do their own data integrity checks anyway and we don't need
multiple layers of it.
I figure "pull-dck" is not a good name, given that one could certainly
read the verb in a way that might be funny for 16year-olds. ;-)
Also, don't hardcode the index URL to use, make it runtime and configure
time configurable instead.
This adds a simply but powerful tool for downloading container images
from the most popular container solution used today. Use it like
this:
# systemd-import pull-dck mattdm/fedora
# systemd-nspawn -M fedora
This will donwload the layers for "mattdm/fedora", and make them
available locally as /var/lib/container/fedora.
The tool is pretty complete, as long as it's only about pulling down
images, or updating them. Pushing or searching is not supported yet.
