status: Explicitly state that the cluster does not exist

[tstromberg]

While debugging a local integration test failure that said the cluster status was "", I dug in and noticed that "minikube status" on a nonexistent cluster emits no error:

host: 
kubelet: 
apiserver: 
kubeconfig: 

This PR changes the behavior to emit an error to stderr, and populate the fields with "Nonexistent":

E0130 14:43:04.992476    7478 status.go:98] The "minikube" cluster does not exist!
host: Nonexistent
kubelet: Nonexistent
apiserver: Nonexistent
kubeconfig: Nonexistent

With -o json, it emits:

E0130 14:43:07.520741    7534 status.go:98] The "minikube" cluster does not exist!
{"Host":"Nonexistent","Kubelet":"Nonexistent","APIServer":"Nonexistent","Kubeconfig":"Nonexistent"} 

[tstromberg]

/ok-to-test

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: tstromberg

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[codecov-io]

Codecov Report

Merging #6438 into master will decrease coverage by 0.03%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #6438      +/-   ##
==========================================
- Coverage   37.68%   37.64%   -0.04%     
==========================================
  Files         128      128              
  Lines        8654     8662       +8     
==========================================
  Hits         3261     3261              
- Misses       4970     4978       +8     
  Partials      423      423

Impacted Files	Coverage Δ
cmd/minikube/cmd/status.go	26.31% <0%> (-2.42%)	⬇️

[minikube-pr-bot]

All Times minikube: [ 92.984026 98.199648 95.280520]
All Times Minikube (PR 6438): [ 94.672726 96.674145 97.683283]

Average minikube: 95.488065
Average Minikube (PR 6438): 96.343385

Averages Time Per Log

+----------------------+-----------+--------------------+
|         LOG          | MINIKUBE  | MINIKUBE (PR 6438) |
+----------------------+-----------+--------------------+
| minikube v           |  0.316215 |           0.300070 |
| Creating kvm2        | 19.843634 |          20.480782 |
| Preparing Kubernetes | 49.317161 |          49.315685 |
| Pulling images       |  3.601241 |           3.723885 |
| Launching Kubernetes | 19.623075 |          19.907964 |
| Waiting for cluster  |  2.730142 |           2.560205 |
+----------------------+-----------+--------------------+

[sharifelgamal]

is the line printed to stderr going to break stuff ingesting the json output?

[tstromberg]

is the line printed to stderr going to break stuff ingesting the json output?

It could: but that's fine with me: stderr is never designed to be parsed, as it may always contain a random unrelated error message.