Re: [atomic-devel] I would like to discuss a new IMAGE label to indicate whether an image is a --system image.

[Giuseppe Scrivano <gscrivan redhat com>]

Hi,

Daniel J Walsh <dwalsh redhat com> writes:

> One problem I have with this is forgetting to use the --system flag when
> installing the container.
>
> I would like to add a LABEL to the image that would tell atomic command
> to install using the --system
>
> method.  This label would not be a generic label, since other tools
> might not implement the concept of a
>
> system container.  I guess we could add a label like
>
> LABEL org.projectatomic.atomic.type=system
>
> Then this would cause atomic to use the --system flag?

Thinking more of it, I am not sure how we can do this automatically for
generic images.  An image can be used either as a system container, or
as a traditional Docker container, so we will need to specify two
different types.

Is it going to be used for images that are usable only as system
containers?

Even in this simplified case, another issue is the storage we are
considering. System images are stored in an OSTree repository.  When we
use --system we are referring to these images.

If we do not explicitely specify the storage then it will be a problem
to know what image we are referring to.  An image can be in a storage
and not in the other, or even worse the two storages could have a
different image referred by the same name.  This will become even more
complicated if in the future we'll need to support more image types.

An alternative would be a label like:

LABEL org.projectatomic.atomic.is_system=true

that says the image can be used as a system container, or even simpler
if the image is stored into the OSTree storage.

When an user tries to install an image that has such label (or present
in OSTree) and no INSTALL label, we could print a message suggesting to
try --system, skipping the automatic assumption of it.

Or alternatively, could we tweak the INSTALL label to print an error
message for images that can be used only as system containers?

Regards,
Giuseppe