kdump to an NFS share require additional configuration (was: Consider adding NFS module to initramfs)

[jbtrystram]

Currently, the nfs kernel module is excluded from initramfs as we don't support root on NFS.
However, this prevents kdump to use NFS as a target for logs.

So maybe we could add back that module, or find a way to enable it only in the kdump case ?

See https://issues.redhat.com/browse/OCPBUGS-31755

[travier]

While looking at something else, I found https://github.com/coreos/fedora-coreos-config/blob/testing-devel/overlay.d/05core/usr/lib/dracut/dracut.conf.d/coreos-omits.conf

[jbtrystram]

yes we explicitely omit it there that's why I opened this

[gursewak1997]

Discussed in the community meeting
This issue should be discussed/fixed with upstream kdump maintainers i.e. i.e. the fix here isn't in our stack, but upstream.

[travier]

We should document how to workaround this issue for kdump.

It should be possible to force the inclusion of the nfs module in the kdump initramfs by passing the --force-add nfs argument to the dracut call via the dracut_args config option in kdump.conf.

[jbtrystram]

@travier another easy way is just to add extra_modules nfs to kdump.conf

Surprisingly dracut_args does not work while extra-modules does. See rhkdump/kdump-utils#11 (comment)

[travier]

We should document how to workaround this issue for kdump.

It should be possible to force the inclusion of the nfs module in the kdump initramfs by passing the --force-add nfs argument to the dracut call via the dracut_args config option in kdump.conf.

Apparently this does not work and is tracked in https://issues.redhat.com/browse/RHEL-26114

[travier]

We should add a test for this case.

[jbtrystram]

openshift/openshift-docs#78300

[travier]

Might be needed related as well: https://gitlab.com/fedora/bootc/base-images/-/merge_requests/32

[licliu]

Hi @jbtrystram @travier, I'd like to fix this issue in kdump rhkdump/kdump-utils#31, but as I commented in rhkdump/kdump-utils#11 (comment), CoreOS's dracut conf may override most dracut varaiables. I suggest to rename them to something like "90-xxxx.conf". Or starting by dracut-104 dracut-ng/dracut-ng@ae81535, --add-confdir is supported, you can move CoreOS specific dracut confs to /usr/lib/dracut/dracut.conf.d/coreos and then use dracut --add-confdir coreos to build initramfs.

[daveyoung]

Hi, I think the dracut config file name issue should be a separate issue, here is a new one created for that: #1837

[jbtrystram]

@licliu @daveyoung I've seen your comments here and in the kexdc-tools issue, but I am away from work for another week. Thanks for looking into that.
I'll do some testing when I am back if no one else from the coreOS team have the time until then

[daveyoung]

@jbtrystram Thanks!