[k8s] Output message when adding a cluster can be improved

[Peter Matulis]

When I add a GKE-based Kubernetes cluster to an existing controller:

$ juju add-k8s -c gce --gke hello-cluster

the following message is printed:

k8s substrate "gke_juju-239814_us-east4_hello-cluster" added as cloud "hello-cluster".

1. I'm uncomfortable with the usage of 'k8s'. This sounds too informal to me. I suggest we use 'Kubernetes' or at least 'K8s' which is what upstream uses [1].

2. The term "substrate" is an internal term. According to recent discussions, it is synonymous with "cloud type". The documentation also does not mention "substrate" anywhere.

3. Anyway, it seems we're referring to an actual "cloud instance" here: the K8s cluster. We can replace "substrate" with "cloud instance" but this introduces a term that is also not used anywhere else to my knowledge. Maybe we should just base the words on the output from `add-cloud`, which would just be:

"Cloud "hello-cluster" successfully added"

As a bonus, this way we do not expose the internal name of the cluster that I do not believe adds anything useful and can be a source of confusion (e.g does the user need to remember this piece of information?).

[1]: https://kubernetes.io/docs/concepts/overview/what-is-kubernetes/#what-kubernetes-and-k8s-mean

[Ian Booth (wallyworld)]

We use "k8s" because that's also idiomatic in the industry, eg
https://medium.com/@rothgar/why-kubernetes-is-abbreviated-k8s-905289405a3c

So far in Juju, we have tended to avoid capitalising abbreviations.

We print the name of the GKE cluster because that's a vitial piece of information the user needs to be aware of - most k8s users also want to still use kubectl for some things.

We could certainly substitute "cluster" for "substrate" in the add-k8s message. The add-cloud message is not sufficient as written since it doesn't convey all the required information.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.