InformationSingle user mode (rescue mode) is used for recovery when the system detects an issue during boot or by manual selection from the bootloader.
Note: The systemctl option --fail is synonymous with --job-mode=fail. Using either is acceptable.
Requiring authentication in single user mode (rescue mode) prevents an unauthorized user from rebooting the system into single user to gain root privileges without credentials.
SolutionEdit /usr/lib/systemd/system/rescue.service and /usr/lib/systemd/system/emergency.service and set ExecStart to use /sbin/sulogin or /usr/sbin/sulogin:
ExecStart=-/bin/sh -c '/sbin/sulogin; /usr/bin/systemctl --fail --no-block default'