How/when nfs is mounted ?

[kserin]

Hello !

I'm currently trying to boot a machine using PXE and NFS mount.

I've generated a dracut initramfs on my Debian12 using the following command: dracut --add-drivers overlay --force /tmp/initrd.img 6.1.0-13-amd64.
And the PXE kernel parameters are: initrd=initrd.img ip=dhcp root=nfs:20.0.1.1:/nfs rd.shell rd.debug

But when I try to boot, I get an initqueue timeout because of the finished/nfsroot.sh script ( https://github.com/dracutdevs/dracut/blob/master/modules.d/95nfs/parse-nfsroot.sh#L124). So I tried to comment the line but the mount does not seem to be done (Logs indicate Failed to switch root: Specified switch root path '/sysroot' does not seem to be an OS tree ).

So I tried to figure out how the NFS mount is done and it seems that nfsroot.sh script do this job : https://github.com/dracutdevs/dracut/blob/master/modules.d/95nfs/nfsroot.sh#L17 and it is installed in /sbin by https://github.com/dracutdevs/dracut/blob/master/modules.d/95nfs/module-setup.sh#L112
But I cannot find where /sbin/nfsroot is called. I probably miss something ... Can someone explain it to me ? :)

[LaszloGombos]

@kserin perhaps you can try with #2269 applied (you might need to build dracut yourself from upstream or at least try to get the patches for the overlay dracut modules).

[kserin]

@LaszloGombos It seems this commit concern overlayfs right ?
For now, I dont try to use overlay. I know I put --add-drivers overlay in dracut command and I might be confusiong. But I did not put any overlay kernel option.
I just try to mount a working NFS.

[kserin]

I succeed to get NFS mount with this patch : master...kserin:dracut:master .
I don't know if it's correct but I still can't figure out how it could work before

[aafeijoo-suse]

And the PXE kernel parameters are: initrd=initrd.img ip=dhcp root=nfs:20.0.1.1:/nfs rd.shell rd.debug

With rd.debug set and without your patch, could you attach /run/initramfs/rdsosreport.txt?

[kserin]

This is the rdsosreport file without my patch.
rdsosreport.txt

[aafeijoo-suse]

AFAIK NFS does not work with systemd-networkd, try adding the network-legacy module to your initramfs.

[kserin]

@aafeijoo-suse I tried to add --add-drivers network-legacy but it still does not work

[aafeijoo-suse]

it's a dracut module, not a kernel module. Try: --add "network network-legacy"

[kserin]

@LaszloGombos @aafeijoo-suse
Should I create a pull request ? I don't see how it can work without calling /sbin/nfsroot script.

[LaszloGombos]

@kserin - we have an NFS test as part of our automation - https://github.com/dracutdevs/dracut/tree/master/test/TEST-20-NFS . I think the NFSv4 part of the test passing on Debian and Ubuntu (without any additional changes).

It would be helpful if you could look at what is the difference between how the test is configured and your setup.