Move rpmdb path from /usr/share/rpm to /usr/lib/sysimage/rpm

[Conan-Kudo]

It's been almost three years since the initial agreement to have a consistent alternative rpmdb path in /usr/lib/sysimage/rpm.

Can we finally move Fedora CoreOS to this path?

(Cloned from coreos/rpm-ostree#1987 at request of @dustymabe)

[cgwalters]

A good bit of the question here hinges on whether we can do this sanely without patching rpm and libsolv. See e.g. openSUSE/libsolv#386
But I think we should be able to explicitly tell libsolv and librpm the path - there's a probable libdnf bug in here last I looked in that it didn't make this configurable.

I think we could lead with FCOS here but it's not an entirely trivial thing to just carry on our own. I'd also e.g. like to switch the container image at least to do this too.

[cgwalters]

If we need to do this by having rpm-ostree explicitly set the path in a bunch of places, it becomes dramatically more fragile.
If instead rpm/libsolv know to try /usr/lib/sysimage/rpm if it exists, things are much more likely to "just work".

Need to consider cases like rebases, as well as the "offline inspection" case. See https://bugzilla.redhat.com/show_bug.cgi?id=1102241 for the latter - which is another one that the sqlite switch will impact too.

[Conan-Kudo]

Don't you already do this to force /usr/share/rpm anyway? That said, I'm open to the idea of a global System-Wide Change in Fedora to that path if you want to go down that road.

[cgwalters]

Let's flip this around: Last time this came up we landed coreos/rpm-ostree#2154 - is there an urgent need to have CoreOS make that symlink canonical today versus just landing the system-wide change and making it not a symlink?

[jlebon]

We discussed this in the meeting today. Our (or at least my) understanding was indeed that this would be a system-wide change and not scoped to just FCOS. I don't have the cycles or knowledge to drive this across all Fedora editions, but if we do go down that path, we can definitely take care of the rpm-ostree-based editions. @Conan-Kudo would you like to drive that change forward?

[Conan-Kudo]

I can help for traditional Fedora variants, if needed. Though I think making the change won't be terribly difficult, evidenced by how @sysrich did this for openSUSE.

[dustymabe]

We discussed this in last week's meeting.

* ACTION: jlebon to reach out to the rpm maintainers to see if the
    relocation of the rpmdb path is something their willing to own for
    F34  (dustymabe, 16:47:11)

[jlebon]

@pmatilai, WDYT about the above? Would you be interested in owning the move to the new rpmdb path with support from the CoreOS team and @Conan-Kudo? Do you have some sense of how difficult/risky this would be?

[pmatilai]

I have no plans or interest to drive such a change, as I have said before.

[pmatilai]

@ffesti, interested?

[dustymabe]

We discussed this at the community meeting this week.

  * ACTION: jlebon to talk with King_InuYasha to see if they can be
    co-captains for the proposed change to move the rpmdb path (#639)
    (dustymabe, 16:41:53)

[dustymabe]

relevant information:

Change Checkpoint: Proposal submission deadline (System Wide Changes) | Tue 2020-12-29
Change Checkpoint: Proposal submission deadline (Self Contained Changes) | Tue 2021-01-19

[cgwalters]

xref coreos/rpm-ostree#2553 where a recent libsolv change to honor %_dbpath (in openSUSE/libsolv@04d4d03 ) broke rpm-ostree (if it'd worked that way from the start we probably could have designed around it at least).

[jlebon]

The Fedora-wide change was done in f36: https://fedoraproject.org/wiki/Changes/RelocateRPMToUsr, but there is still work pending on the rpm-ostree side to fully adapt to it.