systemd: job for X.service failed (control process exited)

What the message looks like

Job for nginx.service failed because the control process exited with error code. See "systemctl status nginx.service" and "journalctl -xeu nginx.service" for details.

Common causes

• Syntax error in the service configuration, e.g. after editing nginx or Postfix.
• Port already in use (“Address already in use”).
• Missing file: certificate, key, socket directory or include.
• Missing permissions, or SELinux/AppArmor blocks access.
• Broken unit or override, e.g. a wrong path in ExecStart.

Check

1. Show status with the last log lines
   systemctl status nginx.service --no-pager -lCopy
2. Show detailed journal entries for the service
   journalctl -xeu nginx.service --no-pager | tail -n 40Copy
3. Test the config (nginx example; Apache apachectl configtest, Postfix postfix check)
   nginx -tCopy
4. Show the unit including all overrides
   systemctl cat nginx.serviceCopy

Fix

• Read the first real error in the journal, not just the systemd summary.
• Fix config errors and always run the service's config test before restarting.
• If the port is busy, find the process with ss -ltnp and stop or reconfigure it.
• After editing units run systemctl daemon-reload.
• Reset the failed state and start again: systemctl reset-failed nginx && systemctl start nginx.

FAQ

What does “control process” mean?

It is the process systemd runs to start, stop or reload the service – ExecStart, ExecStartPre or ExecReload. Its exit code was not 0.

Why does systemctl status not show the cause?

Status only shows the last lines. journalctl -xeu name.service shows the full history, and the error is often a few lines further up.