Re: [atomic-devel] Consiering a host UID/GID upgrade discontinuity (breaking CentOS7 Atomic and F22)

[Colin Walters <walters verbum org>]

On Wed, May 6, 2015, at 04:22 PM, Stephen Gallagher wrote:
> 
> No, I think you're absolutely right that we need to fix this before it goes too far, but my concern is that it's already too late to do it for this cycle. I think what you need to do is make that change in Rawhide immediately and work with docs, marketing and Ambassadors to let people know that Fedora 22's release won't be future-compatible with Fedora 23 and CentOS, but changes are being made to avoid such breakage in the future. This gives you time to optimize the migration plan and users awareness of the upcoming one-time hassle.

I see you arguing two somewhat contradictory things here.  First, you are (correctly) arguing that a reliable transition is hard.  Your examples of system uid data on NFS/etc is a good one.

Then you're arguing that it makes sense to do in F23.  Do we really expect that the additional time will allow a sufficiently robust script to be developed?

One other *major* factor to consider here - Fedora 21 only shipped a Atomic as a cloud image, and while one can certainly possible to treat them as pets, I suspect the majority treat them as cattle - disposable, data is stored on externally mounted volumes, so you can "upgrade" without ostree by just booting a new image.

But Fedora 22 will ship (hopefully) Atomic as a bare metal installer.  And it's a lot more common to have bare metal pets[1].  I'd argue that the strengths of OSTree really come much more to the fore when used on bare metal.  So I'd like to ensure these installations will be upgradeable forever.

[1] There are some times in computing where what one writes must sound really quite strange to those outside of the industry.