cyclic dependencies, cloud-init.target has After=mutli-user.target

[Isabelle COWAN-BERGMAN]

cloud-init.target is ordered after mutli-user.target as it contains the After=mutli-user.target directive. Advice is given in https://github.com/canonical/cloud-init/blob/7d57fcff6d32fd706dd745315c0f8f72d94385eb/systemd/cloud-init.target#L7-L9:
> # system configuration tasks have completed. To order a service after cloud-init
> # is done, add the directives as applicable:
> # After=cloud-init.target and Wants=cloud-init.target

Following this advice will result in cyclic dependencies in systemd resolution if these directives are added to a unit which is WantedBy=multi-user.target. This is because the unit depending on and scheduled after cloud-init.target is WantedBy mutli-user.target as well which is itself ordered Before cloud-init.target. As adding new units to mutli-user.target is standard practice, this is likely to occur frequently. Related issues have been mentioned before in cloud-init bugs, for example: https://bugs.launchpad.net/ubuntu/+source/cloud-init/+bug/1629797/comments/11; as well as other bug trackers: https://bugzilla.redhat.com/show_bug.cgi?id=1393094.

This could be resolved by either of the two:
* removing the advice that results in cyclic dependencies
* cloud-init.target depends on basic.target

Additional information

Cloud provider: any

[James Falcon (falcojr)]

That's why the statement contains the phrase "as applicable". If you have a unit that is "WantedBy=multi-user.target" then by definition, you don't want it running after cloud-init.target, so this advice isn't applicable to your use case. The advice is provided to inform a user how to order something after cloud-init has run, not how avoid all cyclic dependencies. Based on this, I'm going to set this to "Invalid", but if there's a deeper issue here that I'm not understanding, please do comment and set the status back to "New".

[James Falcon (falcojr)]

Tracked in Github Issues as https://github.com/canonical/cloud-init/issues/4068