SUSE Linux Enterprise 15 systems support an "interactive boot" option that can
be used to prevent services from being started. On a SUSE Linux Enterprise 15
system, interactive boot can be enabled by providing a 1,
yes, true, or on value to the
systemd.confirm_spawn kernel argument in /etc/default/grub.
Remove any instance of systemd.confirm_spawn=(1|yes|true|on)
from
the kernel arguments in that file to disable interactive boot.
Recovery booting must also be disabled. Confirm that
GRUB_DISABLE_RECOVERY=true is set in /etc/default/grub.
It is also required to change the runtime configuration, run:
/usr/bin/grub2-editenv - unset systemd.confirm_spawn>
grub2-mkconfig -o /boot/grub2/grub.cfg