systemd Error Messages

Init system, systemctl and journalctl.All systemd pages

Failed to start nginx.service: Unit nginx.service not found.systemctl prints Unit not found when no unit with that name is loaded: a typo, a missing package, a user unit, or a new unit file added before daemon-reload.
Job for nginx.service failed because the control process exited with error codesystemctl start fails with the control process exited with error code when the start command returned non-zero. Read journalctl -xeu NAME for the cause.
System has not been booted with systemd as init system (PID 1). Can't operate.systemctl fails with System has not been booted with systemd in WSL, Docker containers and chroots, where PID 1 is not systemd. Enable it or run apps directly.
systemd: myapp.service: Start request repeated too quickly.systemd logs Start request repeated too quickly when a unit hits its start limit, 5 starts in 10 seconds by default. Fix the crash, then run reset-failed.