Update MINIKUBE_HOME usage

[tony-sol]

Resolves #15835

Make MINIKUBE_HOME env variable usage more convenient with backward compatibility.

Current logic of MINIKUBE_HOME env usage isn't really obvious:

• If env var is not set, it uses ${HOME}/.minikube as default.
• If env var is set, it checks its basename (for some reason??):
  • If basename equals .minikube - use env var
  • Else it appends .minikube to env var value (for some reason??)

It's very implicit logic and goes against the conventional use of *_HOME env vars.

With this changes, the logic changes a bit:

• If env var is not set, it uses ${HOME}/.minikube as default (as it's now)
• If env var is set, it checks its basename (as it's now)
  • If basename equals .minikube - use env var (as it's now)
  • Else it checks existence of .minikube inside path, provided via env var (for backward compatibility)
    • If ${MINIKUBE_HOME}/.minikube exists - use this legacy path (for backward compatibility)
    • Else - use MINIKUBE_HOME as is (new)

So, here is example cases:

1. Env is unset:

   $ export MINIKUBE_HOME=""
   $ # run minikube
   $ ls -hAF ~ | grep minikube
   .minikube/
   $ ls -hAF ~/.minikube
   addons/   cache/    certs/    config/   files/    logs/     machines/
   

2. Env is set AND its basename is .minikube:

   $ export MINIKUBE_HOME="${XDG_DATA_HOME}/.minikube"
   $ # run minikube
   $ ls -hAF $XDG_DATA_HOME | grep minikube
   .minikube/
   $ ls -hAF $XDG_DATA_HOME/.minikube
   addons/   cache/    certs/    config/   files/    logs/     machines/
   

3. Env is set AND its basename is not .minikube AND there is NO .minikube inside:

   $ export MINIKUBE_HOME="${XDG_DATA_HOME}/minikube"
   $ ls -hAF $MINIKUBE_HOME
   $ # MINIKUBE_HOME is empty
   $ # run minikube
   $ ls -hAF $MINIKUBE_HOME
   addons/   cache/    certs/    config/   files/    logs/     machines/
   

4. Env is set AND its basename is not .minikube AND there is .minikube inside provided path:

   $ export MINIKUBE_HOME="${XDG_DATA_HOME}/minikube"
   $ ls -hAF $MINIKUBE_HOME
   .minikube/
   $ # MINIKUBE_HOME has state from previous version
   $ # run minikube
   $ ls -hAF $MINIKUBE_HOME
   .minikube/
   $ ls -hAF $MINIKUBE_HOME/.minikube
   addons/   cache/    certs/    config/   files/    logs/     machines/
   

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: tony-sol / name: Tony Soloveyv (6f03675)

[minikube-bot]

Can one of the admins verify this patch?

[k8s-ci-robot]

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[k8s-ci-robot]

Hi @tony-sol. Thanks for your PR.

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[spowelljr]

/ok-to-test

[minikube-pr-bot]

kvm2 driver with docker runtime

+----------------+----------+---------------------+
|    COMMAND     | MINIKUBE | MINIKUBE (PR 18648) |
+----------------+----------+---------------------+
| minikube start | 47.9s    | 51.0s               |
| enable ingress | 25.7s    | 25.2s               |
+----------------+----------+---------------------+

Times for minikube start: 48.1s 46.9s 48.9s 48.3s 47.0s
Times for minikube (PR 18648) start: 47.6s 50.4s 51.5s 54.1s 51.3s

Times for minikube ingress: 24.5s 27.0s 28.0s 25.0s 24.0s
Times for minikube (PR 18648) ingress: 27.5s 23.9s 25.0s 24.0s 25.5s

docker driver with docker runtime

+----------------+----------+---------------------+
|    COMMAND     | MINIKUBE | MINIKUBE (PR 18648) |
+----------------+----------+---------------------+
| minikube start | 23.1s    | 23.2s               |
| enable ingress | 21.9s    | 22.2s               |
+----------------+----------+---------------------+

Times for minikube ingress: 21.3s 21.8s 21.8s 22.8s 21.8s
Times for minikube (PR 18648) ingress: 21.8s 21.8s 22.8s 22.8s 21.8s

Times for minikube start: 23.3s 24.0s 21.0s 23.6s 23.7s
Times for minikube (PR 18648) start: 23.7s 24.5s 24.2s 21.8s 21.8s

docker driver with containerd runtime

+----------------+----------+---------------------+
|    COMMAND     | MINIKUBE | MINIKUBE (PR 18648) |
+----------------+----------+---------------------+
| minikube start | 21.0s    | 20.8s               |
| enable ingress | 29.6s    | 31.9s               |
+----------------+----------+---------------------+

Times for minikube start: 20.4s 18.8s 22.2s 20.3s 23.0s
Times for minikube (PR 18648) start: 20.0s 19.9s 23.3s 20.6s 20.2s

Times for minikube ingress: 32.8s 32.3s 18.8s 32.3s 31.8s
Times for minikube (PR 18648) ingress: 31.8s 32.3s 32.3s 32.3s 30.8s

[minikube-pr-bot]

These are the flake rates of all failed tests.

Environment	Failed Tests	Flake Rate (%)
Docker_Linux_crio	TestMultiControlPlane/serial/RestartCluster (gopogh)	2.08 (chart)

To see the flake rates of all tests by environment, click here.

[spowelljr]

Looks good to me, thanks for the PR!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: spowelljr, tony-sol

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