Re: [atomic-devel] Documenting "rpm-ostree override"

[Micah Abbott <miabbott redhat com>]

On 05/17/2018 11:04 AM, Chris Negus wrote:
> Thanks. I added a write-up of "rpm-ostree override" to the Atomic Install and Config guide (currently in QA). I'd be glad for any comments:
>
>    https://access.qa.redhat.com/documentation/en-us/red_hat_enterprise_linux_atomic_host/7/html-single/installation_and_configuration_guide/#overriding_an_existing_rpm_package

The changes for `rpm-ostree override` look good, but I noticed that 
earlier in that chapter I noticed that we are still telling folks to use 
`ostree admin undeploy` and `ostree admin cleanup`.  While those 
commands still work, it is preferred to use `rpm-ostree cleanup`.

You can pass in various flags to the `cleanup` command to affect how it 
operates:

  -b, --base            Clear temporary files; will leave deployments 
unchanged
  -p, --pending         Remove pending deployment
  -r, --rollback        Remove rollback deployment
  -m, --repomd          Delete cached rpm repo metadata


> -- Chris Negus
>
> ----- Original Message -----
> > On Tue, May 15, 2018 at 3:51 PM, Chris Negus <cnegus redhat com> wrote:
> > > In the wake of James Mills' excellent article on replacing docker in Atomic
> > > (https://access.redhat.com/solutions/3414221), I realized we had missed
> > > documenting "rpm-ostree override" in the RHEL Atomic user docs. I'll point
> > > to that article, but I want to add some new content as well.
> > >
> > > As I've played around with rpm-ostree override, a few questions have come
> > > up:
> > >
> > > * Can someone suggest a good package to use to override an Atomic package
> > > in the base system? Each package I try fails with some dependency issues I
> > > don't know how to get around.
> >
> > Hmm, interesting -- can you share an example? Remember you'll want to
> > pass it all the related packages.
> > Any leaf package is easy for demo purposes. E.g. strace is probably a good
> > one.
> > Though a more realistic example is probably more convincing. If you
> > don't want to copy the docker one, maybe openssh?
> > I just tried this here:
> >
> > ```
> > rpm-ostree override replace openssh-7.4p1-15.el7.x86_64.rpm
> > openssh-clients-7.4p1-15.el7.x86_64.rpm
> > openssh-server-7.4p1-15.el7.x86_64.rpm
> > ```
> >
> > We've also done some work upstream recently to fully support systemd
> > and kernel replacements.
> > https://github.com/projectatomic/rpm-ostree/releases/tag/v2018.5
> >
> > > * Must a base system package always be removed before it is replaced?
> >
> > Nope, the `override replace` operation will take care of that.
> >
> > > * Is there a proper way to back out, if you decide you want to go back to
> > > the original packages?
> >
> > For specific packages: `override reset $pkg1 $pkg2 ...`
> > To clear *all* overrides: `override reset --all`