[lxc-devel] [PATCH v2] Add Oracle Linux template

[Dwight Engen]

On Tue, 2 Oct 2012 09:16:22 -0500
Serge Hallyn <serge.hallyn at canonical.com> wrote:

> Quoting Dwight Engen (dwight.engen at oracle.com):
> > On Mon, 1 Oct 2012 12:27:16 -0500
> > Serge Hallyn <serge.hallyn at canonical.com> wrote:
> > 
> > > Quoting Dwight Engen (dwight.engen at oracle.com):
> > > > 
> > > > This is a new template to create containers based on an Oracle
> > > > Linux rootfs image. The path to the rootfs must be given to the
> > > > template, and if it resides on a btrfs will be snapshoted
> > > > rather than copied.
> > > > 
> > > > Signed-off-by: Dwight Engen <dwight.engen at oracle.com>
> > > 
> > > Hi,
> > > 
> > > maybe it's in here and I'm missing it, but where is the
> > > $template_rootfs to come from?  Is there a repository online where
> > > they can be fetched? If so, can auto-wget'ing be added to the
> > > template?
> > > 
> > > -serge
> > 
> > $template_rootfs is a required template argument, so you have to
> > give -- -t /path/to/templaterootfs to lxc-create. The idea is that
> > you have a rootfs already created/extracted into a btrfs subvolume
> > that then gets snapshoted into the container instance each time you
> > do an lxc-create. I think this is similar to the ubuntu-cloud
> > template, but the
> 
> The ubuntu-cloud template takes that as an optional argument, and will
> automatically wget the tarball if it doesn't exist.  That's what I was
> suggesting that you do.
> 
> And to be clear I'm not saying inclusion of the template upstream
> ought to block on that.

Yeah, so thats what I'm doing too is to make the -t optional, and
if you don't give it, it will download and create a rootfs from rpms.
That way users can create the rootfs themselves or specify a -R release
to have the template make one for them.

> > template doesn't do the fetching and setup of the template rootfs.
> > 
> > I can look into setting up the template rootfs from rpms, or an
> > image if that is required, but I think its useful also for the
> > template rootfs to be user specifiable as well.
> 
> Agreed, I have no objection to the option.
> 
> > How do you handle for example if
> > you want one template rootfs to be a webserver, and another one for
> > a database? Do you intend for that to be done post lxc-create with
> > some configuration management (ala puppet) tool? It seems like this
> > would work, but would make bigger differences per container
> > instance to the template, so if you plan to instantiate many
> > container instances it could add up.
> 
> (Not saying you should go this route, but) the way I address this is
> to create canonical containers (lvm-based though btrfs-based works
> too) and then lxc-clone them.

Right, this is I think very similar to what I was going for with the
template rootfs. 

> Thanks for the template.

Thanks, I'll post a new patch once I get the rpm download thing working.