Use systemctl flag --verbose to show errors directly when starting a container service

[eriksjolund]

Here is a minimal demo showing a new feature in systemd.

Requirements: systemd 258 or later.

1. Boot up a linux system having systemd 258.
2. Log in as an unprivileged user
3. mkdir -p ~/.config/containers/systemd
4. Create file ~/.config/containers/systemd/demo.container containing

   [Container]
   Image=docker.io/library/alpine
   Exec=non-existing-path
   

5. Reload the system manager

   systemctl --user daemon-reload
   

6. Start the service

   systemctl --user --verbose start demo.service
   

   The following output is printed

   Job for demo.service failed because the control process exited with error code.
   See "systemctl --user status demo.service" and "journalctl --user -xeu demo.service" for details.
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: Starting demo.service...
   Sep 20 07:47:43 localhost.localdomain podman[1807]: 2025-09-20 07:47:43.372352218 +0000 UTC m=+0.027909538 container create 0fda39184514a3d2dcb2655fd36fe51ccb26260d56131136dedf9f77b975d1ea (image=docker.io/library/alpine:latest, name=systemd-demo, PODMAN_SYSTEMD_UNIT=demo.service)
   Sep 20 07:47:43 localhost.localdomain conmon[1827]: conmon 0fda39184514a3d2dcb2 <nwarn>: runtime stderr: executable file `non-existing-path` not found in $PATH: No such file or directory
   Sep 20 07:47:43 localhost.localdomain conmon[1827]: conmon 0fda39184514a3d2dcb2 <error>: Failed to create container: exit status 1
   Sep 20 07:47:43 localhost.localdomain podman[1807]: 2025-09-20 07:47:43.411674192 +0000 UTC m=+0.067231553 container remove 0fda39184514a3d2dcb2655fd36fe51ccb26260d56131136dedf9f77b975d1ea (image=docker.io/library/alpine:latest, name=systemd-demo, PODMAN_SYSTEMD_UNIT=demo.service)
   Sep 20 07:47:43 localhost.localdomain demo[1807]: Error: crun: executable file `non-existing-path` not found in $PATH: No such file or directory: OCI runtime attempted to invoke a command that was not found
   Sep 20 07:47:43 localhost.localdomain podman[1807]: 2025-09-20 07:47:43.362900666 +0000 UTC m=+0.018458028 image pull 02f8efbefad605a169e89926147edd0676646263268f303c6fb3cdfdbc4a9612 docker.io/library/alpine
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: demo.service: Main process exited, code=exited, status=127/n/a
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: demo.service: Killing process 1827 (conmon) with signal SIGKILL.
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: demo.service: Killing process 1830 (podman) with signal SIGKILL.
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: demo.service: Failed with result 'exit-code'.
   Sep 20 07:47:43 localhost.localdomain systemd[1213]: Failed to start demo.service.
   

Side note 1:

If you try the --verbose flag on a linux systemd having systemd 257 the command fails

$ systemctl --user --verbose demo.service
systemctl: unrecognized option '--verbose'

Side note 2:

To try it out on a Linux system with systemd 258, I booted up a Fedora CoreOS vm

(rawhide
https://builds.coreos.fedoraproject.org/browser?stream=rawhide&arch=aarch64)

with the help of the tool vfkit on a macbook.

Side note 3:

See also this Mastodon post about the functionality by Lennart Poettering:
https://mastodon.social/@pid_eins/114545892813068498

Side note 4:

There is a minor bug that is labeled for the systemd 259 milestone:

• systemctl --verbose start demo.service prints log output from previous service lifecycle systemd/systemd#39048