[CentOS-devel] how minimal is a minimal too minimal

Wed Mar 19 17:44:07 UTC 2014
Chris St. Pierre <chris.a.st.pierre at gmail.com>

I think we need to take into account that there are multiple different
purposes for a minimal image.  If I'm using the minimal image in Docker, I
don't want or need sshd.  In other (non-container) places, I probably do.
 So maybe we need more than one minimal (or micro) -- 'micro' (outrageously
small image for outrageously small machines) and 'micro-lxc' (even smaller
image for even smaller containers).

I definitely think yum should be included, though.  I should be able to
'RUN yum -y install ...' in my Dockerfile without first invoking some ugly
'RUN rpm -hvU http://...' mess.

One of the many cool things about containers is that we can really almost
eliminate all of the userspace except for the application itself.  With
that in mind, including yum is probably a violation of Twelve Factor
(specifically, http://12factor.net/build-release-run), but the Docker build
process doesn't really permit truly strict separation of build and run
toolsets, just of the stages.  As LXC tools continue to evolve, though,
there may be a use case for a micro image without even yum, with the
assumption that the build stage will be accomplished by an external
toolset.  That'll be an opportunity to really experiment with how much
userspace we can pull out of CentOS.

On Wed, Mar 19, 2014 at 1:27 PM, Les Mikesell <lesmikesell at gmail.com> wrote:

> On Wed, Mar 19, 2014 at 12:14 PM, Jeff Sheltren <jeff at tag1consulting.com>
> wrote:
> >
> > Related questions we struggle with in Fedora: what about i18n and docs?
> If
> > no docs, docs at all, not even man pages?
> >
> >
> >
> > "No docs at all" makes a lot of sense to me if we're going for truly
> > minimal.  The main issue I see with that is making end-users aware that
> they
> > better know what they're doing if they're installing this version.
> Normally when you install a minimal version you already have a plan
> for what you will do next.  In my case I want the least possible user
> intervention (or network infrastructure support) to get a system to
> the point where I can ssh in and complete the setup because people in
> remote locations that are more familiar with other OS's may have to do
> it.  I'd prefer for sshd and yum to work and to have openssh-clients
> and rsync installed, but it wouldn't be a showstopper if it took an
> extra scripted step to get yum going.   I'd gladly trade that for an
> easier way to do the initial network setup when you have multiple NICs
> and no DHCP (like showing you the one(s) with link up).
> --
>    Les Mikesell
>      lesmikesell at gmail.com
> _______________________________________________
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Chris St. Pierre
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