Description of problem:
NFS root with dracut-generated initramfs no longer works in Fedora. /sysroot cannot be mounted, as generated sysroot.mount unit is bad:

(in initrd recovery shell)
# systemctl status sysroot.mount
o sysroot.mount - /sysroot
     Loaded: loaded (/proc/cmdline: generated)
     Active: inactive (dead)
      Where: /sysroot
       What: nfs:192.168.137.2:/home/poligon/daresbalat-rootfs:vers=3,tcp,local_lock=none,soft
       Docs: man:fstab(5)
             man:systemd-fstab-generator(8)
(no logs)

Issuing "systemctl start sysroot.mount" hangs.

The "What" is formatted completely wrong and "mount" cannot parse it:
- "nfs:" prefix is superfluous
- mount options are appended to remote path

My full ipxe kernel command line is:

kernel https://pipebreaker.pl/vmlinuz initrd=initramfs ip=dhcp root=nfs:192.168.137.2:/home/poligon/daresbalat-rootfs:vers=3,tcp,local_lock=none,soft selinux=0 rw systemd.log_target=console systemd.debug_shell log_buf_len=1M rd.retry=15



Version-Release number of selected component (if applicable):
systemd-250-3.fc36.x86_64
dracut-055-8.fc36.x86_64
but probably appeared long ago. My last working initramfs is initramfs-5.12.0-198.fc35.x86_64.img, built around April 2021.


How reproducible:
Always

Steps to Reproduce:
1. Have root-nfs setup
2. Try to boot over the network
3.

Actual results:
After the timeout waiting for nfs root hook, dracut drops to the shell.

Expected results:
Boot should continue.

Additional info:
1) fstab-generator has some code for handling nfsroot:
https://github.com/systemd/systemd/blob/v250/src/fstab-generator/fstab-generator.c#L711

but it checks for "/dev/nfs" which is deprecated in dracut:

 root=/dev/nfs nfsroot=[<server-ip>:]<root-dir>[:<nfs-options>]
           Deprecated!  kernel Documentation_/filesystems/nfsroot.txt_
           defines this method. This is supported by dracut, but not
           recommended.
https://man7.org/linux/man-pages/man7/dracut.cmdline.7.html

I've tried with this deprecated setting, but it did not help.


2) my dracut configuration:

 dracut.conf.d# bat *
───────┬─────────────────────────────────────────────────────────────────────────────────────────────
       │ File: networkd-config.conf
───────┼─────────────────────────────────────────────────────────────────────────────────────────────
   1   │  # manually install files needed for systemd-networkd
   2   │ install_items+=" /etc/systemd/network/* "
   3   │ 
   4   │ add_dracutmodules+=" systemd-networkd systemd-resolved systemd-sysusers "
───────┴─────────────────────────────────────────────────────────────────────────────────────────────
───────┬─────────────────────────────────────────────────────────────────────────────────────────────
       │ File: no_hostonly.conf
───────┼─────────────────────────────────────────────────────────────────────────────────────────────
   1   │ hostonly="no"
───────┴─────────────────────────────────────────────────────────────────────────────────────────────
───────┬─────────────────────────────────────────────────────────────────────────────────────────────
       │ File: trim-modules.conf
───────┼─────────────────────────────────────────────────────────────────────────────────────────────
   1   │ 
   2   │ # lvm is needed by Ceph OSD on LVM
   3   │ # rootfs-block is required by lvm
   4   │ # dm is required by lvm
   5   │ omit_dracutmodules+=" rdma crypt mdraid multipath qemu qemu-net iscsi lunmask nbd resume "
───────┴─────────────────────────────────────────────────────────────────────────────────────────────



3) I need to use IP address for server, because since dracut switched to systemd-networkd, DNS resolution in initramfs no longer works (systemd-resolved is required, but it cannot start in initramfs due to missing USER); but that's another bug.