Charm uses hostnamectl json format args which don't exist on focal

[Adam Dyess]

When detecting the underlying cloud

hostnamectl: unrecognized option '--json=short'

--- during this situation, the error handling code fails to log the error correctly.

        try:
            hostnamectl = check_output(["hostnamectl", "--json=short"])
        except CalledProcessError as e:
- log.warning("hostnamectl failure", e)
+ log.warning("hostnamectl failure: %s", e)
            return None

is the required minimum, but new logic must be employed to find the correct values from hostnamectl

[Adam Dyess (addyess)]

Works fine in jammy, but fails in focal due to lack of arguments

[Adam Dyess (addyess)]

https://github.com/charmed-kubernetes/charm-lib-interface-external-cloud-provider/pull/2

[Adam Dyess (addyess)]

Backport complete for each
https://github.com/charmed-kubernetes/charm-kubernetes-control-plane/commit/13fb7c92343cc15db0afea9f2e0054cc4924c200
https://github.com/charmed-kubernetes/charm-kubernetes-worker/commit/890d0dc6bbcbc59bf501037b1fdd7a4f3dd2f309

[Adam Dyess (addyess)]

https://github.com/charmed-kubernetes/charm-lib-interface-external-cloud-provider/pull/3
Fix for vsphere clouds