system76-dkms fails to install with ostree

[phtown]

Distribution (run cat /etc/os-release):

NAME="Fedora Linux"
VERSION="35.20211206.0 (Kinoite)"
ID=fedora
VERSION_ID=35
VERSION_CODENAME=""
PLATFORM_ID="platform:f35"
PRETTY_NAME="Fedora Linux 35.20211206.0 (Kinoite)"
ANSI_COLOR="0;38;2;60;110;180"
LOGO=fedora-logo-icon
CPE_NAME="cpe:/o:fedoraproject:fedora:35"
HOME_URL="https://fedoraproject.org/"
DOCUMENTATION_URL="https://docs.fedoraproject.org/en-US/fedora-kinoite/"
SUPPORT_URL="https://ask.fedoraproject.org/"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=35
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=35
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Kinoite"
VARIANT_ID=kinoite
OSTREE_VERSION='35.20211206.0'

Related Application and/or Package Version (run apt policy $PACKAGE NAME):

rpm-ostree:
 Version: '2021.14'
 Git: 5cb5980ad94eaaee0585b8dde1a733cb12670b19
 Features:
  - compose
  - rust
  - fedora-integration

Issue/Bug Description:

Trying to install system76-dkms from Copr with rpm-ostree gives

error: Running %post for system76-dkms: bwrap(/bin/sh): Child process killed by signal 8; run `journalctl -t 'rpm-ostree(system76-dkms.post)'` for more information

Running that command gives

Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[8908]: Error! No write access to DKMS tree at /var/lib/dkms
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[8927]: Error! No write access to DKMS tree at /var/lib/dkms
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[8947]: Creating symlink /var/lib/dkms/system76/0.22/source -> /usr/src/system76-0.22
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[8998]: mkdir: cannot create directory ‘/var/lib/dkms’: Read-only file system
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[8999]: ln: failed to create symbolic link '/var/lib/dkms/system76/0.22/source': No such file or directory
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[9007]: ls: cannot access '/var/lib/dkms/system76/0.22/source': No such file or directory
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[9010]: Error! The directory /var/lib/dkms/system76/0.22/source does not appear to have module source located within it.
Dec 06 20:04:21 galago rpm-ostree(system76-dkms.post)[9010]: Build halted.

Steps to reproduce (if you know):

sudo rpm-ostree install system76-dkms

Expected behavior:

system76-dkms installs without error.

Other Notes:

This also affects system76-io-dkms and system76-acpi-dkms.
I know this is a relatively rare usecase that might be difficult to fix, so I understand if it's not a priority. Thank you for all your work on this project.

[strugee]

This is a downstream bug: coreos/rpm-ostree#1091

[BlauerHunger]

The problem is dkms itself because it's not compatible with the immutable base system. Akmods, the official way of providing dynamic kernel modules on Fedora distros, works well. If you could package these modules as akmod packages (or at least .spec files so users can build their own packages), that would be great. See here for more info on akmod.