kubeadm: add test to detect panics when given certain feature gates

[ereslibre]

What type of PR is this?
/kind feature

What this PR does / why we need it:
This integration test allows us to detect if a given feature gate will
panic kubeadm. This builds on the assumption that a golang panic makes
the process exit with the code 2.

These tests are not trying to check if the init process succeeds or
not, their only purpose is to ensure that the exit code of the
kubeadm init invocation is not 2, thus, reflecting a golang panic.

Some refactors had to be made to the test code, so we return the exit
code along with stdout and stderr.

Which issue(s) this PR fixes:
Fixes kubernetes/kubeadm#1803

Does this PR introduce a user-facing change?:

NONE

/assign @neolit123
/assign @Arvinderpal

[k8s-ci-robot]

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In response to this:

What type of PR is this?
/kind test

What this PR does / why we need it:
This integration test allows us to detect if a given feature gate will
panic kubeadm. This builds on the assumption that a golang panic makes
the process exit with the code 2.

These tests are not trying to check if the init process succeeds or
not, their only purpose is to ensure that the exit code of the
kubeadm init invocation is not 2, thus, reflecting a golang panic.

Some refactors had to be made to the test code, so we return the exit
code along with stdout and stderr.

Which issue(s) this PR fixes:
Fixes kubernetes/kubeadm#1803

Does this PR introduce a user-facing change?:

NONE

/assign @neolit123
/assign @Arvinderpal

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[k8s-ci-robot]

@ereslibre: The label(s) kind/test cannot be applied. These labels are supported: api-review, community/discussion, community/maintenance, community/question, cuj/build-train-deploy, cuj/multi-user, platform/aws, platform/azure, platform/gcp, platform/minikube, platform/other

In response to this:

What type of PR is this?
/kind test

What this PR does / why we need it:
This integration test allows us to detect if a given feature gate will
panic kubeadm. This builds on the assumption that a golang panic makes
the process exit with the code 2.

These tests are not trying to check if the init process succeeds or
not, their only purpose is to ensure that the exit code of the
kubeadm init invocation is not 2, thus, reflecting a golang panic.

Some refactors had to be made to the test code, so we return the exit
code along with stdout and stderr.

Which issue(s) this PR fixes:
Fixes kubernetes/kubeadm#1803

Does this PR introduce a user-facing change?:

NONE

/assign @neolit123
/assign @Arvinderpal

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.

[neolit123]

thanks @ereslibre

/lgtm
/approve

[neolit123]

/retest

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ereslibre, neolit123

The full list of commands accepted by this bot can be found here.

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Needs approval from an approver in each of these files:

• cmd/kubeadm/OWNERS [ereslibre,neolit123]

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[neolit123]

/priority important-longterm