pacman -S linux-headers will do this, yes.
As you said, Arch is a rolling distro, which is why this will install
almost always a higher version than the ISO kernel is, except you
download the ISO on release, so... almost always higher.
Like for me right now, ISO Kernel 7.2.2 and installing "pacman -S linux
linux-headers" will install 7.2.6 which builds modules against 7.2.6
which is incompatible for the booted ISO kernel.
what do mean? DKMS builds against the installed kernel(s). in
ArchISO's case, the ISO's kernel if you're in the ISO runtime, or the
target's installed version if you're chrooted into it.
And exactly that is my point... to be able to build against the ArchISO
kernel version, you will have to download and install the corresponding
version of linux-headers package from the archive... always.
This is not very user-friendly and in fact this makes he ISO unusable
for offline purposes which require bcachefs.
and if you're not putting / on bcachefs, just do it post-install. no
bog deal.
Even though it makes ArchISO an unnecessary burden for handling bcachefs
filesystems out-of-the-box and it shouldn't be a point for what someone
might want to use bcachefs.
- same goes for older ISO images one might want to use because there
is currently no way to get current ISO
1. Arch is a rolling distro. what one "might want" to use is not
supported if it's not current stable.
Just because it is a rolling distro it shouldn't require one having an
internet connection for basic tasks like mounting a filesystem, altough
it's tools (bcachefs-tools) are already included in the ISO.
2. but also see above re: DKMS- you're more liable to run into
chrooting/glibc issues or the like before you run into DKMS issues
because of an older ISO.
You might be right regarding kernel version compatibility in general but
this also partly supports my request to include the module in the
ArchISO imo... to avoid such issues (chrooting/glibc).
My points are just:
- bcachefs-tools are installed (most likely useless)
- is takes a couple of extras steps to get the module (remounting,
downloading headers from the archive, installing, building)
- not beginner friendly
- ArchISO not suitable for offline use
My question is, what's the matter with including the bcachefs DKMS
module in the Arch releng ISO?
Best regards,
DMC
On 9/15/26 4:04 AM, brent s. wrote:
On Sep 13, 2026 17:29, DMC <[email protected]> wrote:
(SNIP)
- you have to download the linux-headers package for the Linux-Kernel
version used in the ISO
pacman -S linux-headers will do this, yes.
- there might be some point where the most current version of
bcachefs-dkms will not compile due to breaking changes in the kernel
what do mean? DKMS builds against the installed kernel(s). in
ArchISO's case, the ISO's kernel if you're in the ISO runtime, or the
target's installed version if you're chrooted into it.
realistically you need to do both if you're putting / on bcachefs, of
course.
unless the target install and ISO kernel version are the same, in
which case you technically can just do it for the ISO runtime and copy
over the modules to the target.
and if you're not putting / on bcachefs, just do it post-install. no
bog deal.
- same goes for older ISO images one might want to use because there
is currently no way to get current ISO
1. Arch is a rolling distro. what one "might want" to use is not
supported if it's not current stable.
2. but also see above re: DKMS- you're more liable to run into
chrooting/glibc issues or the like before you run into DKMS issues
because of an older ISO.
3. but also also, this shouldn't matter either.[0][1](etc.)
- need to find a working bcachefs version for the current kernel
version
see above re: DKMS, but assuming your ISO is somehow THAT old that the
normal path doesn't work, see the ALA.[2]
[0]
https://wiki.archlinux.org/title/Install_Arch_Linux_from_existing_Linux
[1] https://wiki.archlinux.org/title/Preboot_Execution_Environment
(Specifically section 1.3 et. al.)
[2] https://wiki.archlinux.org/title/Arch_Linux_Archive
