[openstack-dev] [TripleO] Installing from packages in tripleo-image-elements

Dan Prince dprince at redhat.com
Wed Jan 8 00:18:56 UTC 2014

----- Original Message -----
> From: "James Slagle" <james.slagle at gmail.com>
> To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org>
> Sent: Tuesday, January 7, 2014 3:53:57 PM
> Subject: Re: [openstack-dev] [TripleO] Installing from packages in	tripleo-image-elements
> On Tue, Jan 7, 2014 at 3:23 PM, Clint Byrum <clint at fewbar.com> wrote:
> > What would be the benefit of using packages?
> We're building images on top of different distributions of Linux.
> Those distributions themselves offer packaged and supported OpenStack
> components.  So, one benefit is that you'd be using what's "blessed"
> by your distro if you chose to.  I think that's a farily common way
> people are going to be used to installing components. The OpenStack
> Installation guide says to install from packages, fwiw.
> > We've specifically avoided packages because they complect[1] configuration
> > and system state management with software delivery. The recent friction
> > we've seen with MySQL is an example where the packages are not actually
> > helping us, they're hurting us because they encode too much configuration
> > instead of just delivering binaries.
> We're trying to do something fairly specific with the read only /
> partition.  You're right, most packages aren't going to handle that
> well.  So, yes you have a point from that perspective.
> However, there are many examples of when packages help you.
> Dependency resolution, version compatibility, methods of verification,
> knowing what's installed, etc.  I don't think that's really an
> argument or discussion worth having, because you either want to use
> packages or you want to build it all from source.  There are
> advantages/disadvantages to both methods, and what I'm proposing is
> that we support both methods, and not require everyone to only be able
> to install from source.

I think James gives a nice summary here. The fact is some people do want to use packages with the OpenStack image elements and we should support them. And from the sounds of it the implementation details aren't going to cost that much. The benefit we get from this is that we as a community can focus in on making a single set of tripleo-image-elements rock solid for both packages and source installs.

> > Perhaps those of us who have been involved a bit longer haven't done
> > a good job of communicating our reasons. I for one believe in the idea
> > that image based updates eliminate a lot of the entropy that comes along
> > with a package based updating system. For that reason alone I tend to
> > look at any packages that deliver configurable software as potentially
> > dangerous (note that I think they're wonderful for libraries, utilities,
> > and kernels. :)
> Using packages wouldn't prevent you from using the image based update
> mechanism.  Anecdotally, I think image based updates could be a bit
> heavy handed for something like picking up a quick security or bug fix
> or the like.  That would be a scenario where a package update could
> really be handy.  Especially if someone else (e.g., your distro) is
> maintaining the package for you.
> For this proposal though, I was only talking about installation of the
> components at image build time.
> --
> -- James Slagle
> --
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