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

[Jonathan Lebon <jlebon redhat com>]

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`