[CentOS-devel] NFSroot over wifi in CentOS 7 - graceful shutdown problem

Hi,

I've got a task to have a small number of laptops netboot Linux over 
WiFi. The kernel is loaded off the USB stick of cource, it's off topic 
for now.

The WPA-supplicant daemon is started early by dracut off initrd. It 
works. Mostly.

The problem is that upon shutdown systemd terminates all the processes 
FIRST and unmounts filesystems NEXT.

Guess what? Upon termination, wpa-supplicant brings the wireless 
interface down and the system hangs being unable to unmount now-defunct 
NFSroot.

There were some discussions regarding similar matter and there's even 
the RH Errata:
https://access.redhat.com/errata/RHBA-2018:2447
But I'm woking on a fully updated CentOS Linux release 7.8.2003 and 
nevertheless I've got the problem.

I don't have rights to see the BZ.
https://bugzilla.redhat.com/show_bug.cgi?id=1593649

I'm deciding to use a quick and dirty hack to do a totally ungraceful 
shutdown/reboot:
https://unix.stackexchange.com/questions/533307/systemd-fails-to-umount-manually-mounted-nfs-shares-in-initramfs

Any better ideas?

Best regards,
	Dmitry Mikhailov.