nfsroot=auto does not work, Ubuntu 22.04

[Konstantin Olchanski]

in scripts/nfs, there is provisions for nfsroot=auto to take NFSROOT value from DHCP "root-path". But it does not work because DHCP root-path option is not written to /run/net-enp1s0f0.conf by etc/dhcp/dhclient-enter-hooks.d/config

to fix this, please add [echo "ROOTPATH='$new_root_path'"] somewhere in etc/dhcp/dhclient-enter-hooks.d/config, rebuild the initrd, copy it to /tftpboot, reboot NFSROOT client, observe ROOTPATH='192.168.0.248:/nfsroot/dsfe05' is present in /run/net-enp1s0f0.conf, change pxelinux config file to say nfsroot=auto, it will work now.

emacs -nw /usr/lib/initramfs-tools/etc/dhcp/dhclient-enter-hooks.d/config
...
                echo "ROOTSERVER='${new_routers%% *}'"
add this ----> echo "ROOTPATH='$new_root_path'"
                echo "HOSTNAME='$new_host_name'"
                echo "DNSDOMAIN='$new_domain_name'"
...

K.O.