RFE: Migrate `/etc` diversions to a private directory instead of `/usr/etc`

[Conan-Kudo]

The current state of using /usr/etc for diverted pristine copies of /etc content is a problem.

1. openSUSE uses /usr/etc which makes bootc fully incompatible with openSUSE.
2. Work done by SUSE to use /usr/etc for the vendor layer of configuration is being upstreamed, and that software is incompatible with bootc.

Could we please move this to somewhere else? Perhaps something like /usr/lib/bootc/pristine-etc or similar?

[Conan-Kudo]

This would also help with issues like #942 as well.

[cgwalters]

This comes from ostree today and is probably best tracked there by default. That said the implementation of this would probably change by default as part of #1190 (ref https://github.com/containers/composefs-rs/blob/6884b989eb33b9400b7b96887a074653009eb6b4/crates/composefs-setup-root/src/main.rs#L263 )

One problem is though that it's possible some things have come to rely on it (even though they shouldn't). We can check today by running tests after doing mount --bind /usr/share/empty /usr/etc in early boot.

There's other details here like even if the composefs-rs change landed we'd need to probably at least keep ostree admin config-diff say working.

[Conan-Kudo]

I did file this as a ticket for rpm-ostree as well: coreos/rpm-ostree#5419

[travier]

This comes from ostree today and is probably best tracked there by default. That said the implementation of this would probably change by default as part of #1190 (ref containers/composefs-rs@6884b98/crates/composefs-setup-root/src/main.rs#L263 )

Agree that it's probably the right place and time to change this. We are looking at this right now and the current composefs-rs implementation does not do any special treatment here so /etc stays "in place" when using the composefs native backend.

We can implement the /etc three way merge in a way that does not rely on it.

One problem is though that it's possible some things have come to rely on it (even though they shouldn't). We can check today by running tests after doing mount --bind /usr/share/empty /usr/etc in early boot.

👍🏻

There's other details here like even if the composefs-rs change landed we'd need to probably at least keep ostree admin config-diff say working.

Yes, we will need an equivalent command in bootc most probably (or cfsctl?) that does that.

[cgwalters]

cc #1485

[tulilirockz]

Turns out this behavior does not break OpenSUSE: https://github.com/bootcrew/opensuse-bootc works perfectly fine there, funnily enough