systemd

The following error has been the bane of my existence for the past few months:

TASK [geerlingguy.containerd : Ensure containerd is started and enabled at boot.] ***
fatal: [instance]: FAILED! => {
  "changed": false,
  "cmd": "/bin/systemctl",
  "msg": "Failed to connect to bus: No such file or directory",
  "rc": 1,
  "stderr": "Failed to connect to bus: No such file or directory",
  "stderr_lines": [
    "Failed to connect to bus: No such file or directory"
  ],
  "stdout": "",
  "stdout_lines": []
}

Since I use Molecule with my Ansible roles and playbooks to test them in identical CI environments both locally and in GitHub Actions, I can maintain an identical environment inside which tests are run. And many of my roles and playbooks need to test whether systemd services are configured and run correctly.

But Docker recently switched from cgroups v1 to cgroups v2, and that started this 'Failed to connect to bus' business—systemd relied on some configuration that was easy enough to add in the past: just run your containers with these options:

For many of my Ansible playbooks and roles, I have CI tests which run over various distributions, including CentOS, Ubuntu, Debian, and Fedora. Many of my Docker Hub images for Ansible testing include systemd so I can test services that are installed inside. For the most part, systemd-related issues are rare, but it seems with Fedora and DNF, I often encounter random test failures which invariably have an error message like:

No such file or directory: '/var/lib/dnf/rpmdb_lock.pid'

The full Ansible traceback is: