Single user mode (rescue mode) is used for recovery when the system detects an issue during boot or by manual selection from the bootloader. Rationale: 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.
Solution
Edit /usr/lib/systemd/system/rescue.service and /usr/lib/systemd/system/emergency.service and set ExecStart to use '/usr/sbin/sulogin': ExecStart=-/bin/sh -c '/usr/sbin/sulogin; /usr/bin/systemctl --job-mode=fail --no-block default' Additional Information: The systemctl option --fail is synonymous with --job-mode=fail. Using either is acceptable.