auth: remove SecurityContextDeny admission plugin

[mtardy]

What type of PR is this?

/kind deprecation

What this PR does / why we need it:

This PR removes the code associated with the SecurityContextDeny admission plugin. More info on why in the associated issue.

Which issue(s) this PR fixes:

Part of #111516

Special notes for your reviewer:

Changes need to be made against https://github.com/kubernetes/test-infra configs before this PR will pass the tests. It was merged a few months ago:

• remove SecurityContextDeny test-infra#29361

Does this PR introduce a user-facing change?

Removed the `SecurityContextDeny` admission plugin, deprecated since v1.27. The [Pod Security Admission](https://k8s.io/docs/concepts/security/pod-security-admission/) plugin, available since v1.25, is recommended instead.

Additional documentation e.g., KEPs (Kubernetes Enhancement Proposals), usage docs, etc.:

- [KEP]: https://kep.k8s.io/3785
- [Other doc]: https://github.com/kubernetes/kubernetes/issues/111516

[k8s-ci-robot]

Skipping CI for Draft Pull Request.
If you want CI signal for your change, please convert it to an actual PR.
You can still manually trigger a test run with /test all

[mtardy]

/sig security
/sig auth

[mtardy]

/test all

[mtardy]

/retest

[pohly]

pull-kubernetes-local-e2e is not passing at the moment, you can ignore that failure if you have checked locally that your proposed change works.

[mtardy]

pull-kubernetes-local-e2e is not passing at the moment, you can ignore that failure if you have checked locally that your proposed change works.

Oh okay, but do you know how I could fix this? I have not run the e2e tests locally.

[pohly]

So you haven't tried your changes to hack/local-up-cluster.sh at all? How did you know that you need to modify it?

[sftim]

BTW, to link to the KEP you can use https://kep.k8s.io/3785

[sftim]

LGTM

[dims]

/assign @liggitt
/lgtm

(local-up-cluster definitely looks good)

[k8s-ci-robot]

LGTM label has been added.

Git tree hash: 367da84eac9eed4650a9a6eaed97869233022d24

[cailynse]

/lgtm

🧼🧽🫧

[cici37]

/remove-sig api-machinery

[sftim]

/retest

[k8s-ci-robot]

@mtardy: The following test failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-kubernetes-local-e2e	73bec0f	link	false	/test pull-kubernetes-local-e2e

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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. I understand the commands that are listed here.

[stlaz]

/triage accepted

[pacoxu]

/milestone v1.30
/priority important-soon

[liggitt]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: liggitt, mtardy

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

The pull request process is described here

Needs approval from an approver in each of these files:

• hack/OWNERS [liggitt]
• pkg/features/OWNERS [liggitt]
• pkg/kubeapiserver/OWNERS [liggitt]
• plugin/pkg/admission/OWNERS [liggitt]
• test/OWNERS [liggitt]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[sftim]

Changelog suggestion:

-Removed the `SecurityContextDeny` admission plugin, deprecated since v1.27. The Pod Security Admission plugin, available since v1.25, is recommended instead. See https://kubernetes.io/docs/reference/access-authn-authz/admission-controllers/#securitycontextdeny for more information.
+Removed the `SecurityContextDeny` admission plugin, deprecated since v1.27.
+The [Pod Security Admission](https://k8s.io/docs/concepts/security/pod-security-admission/) plugin,
+available since v1.25, is recommended instead.

We can't link to the (removed) docs for a removed admission controller.

[mtardy]

Changelog suggestion:

-Removed the `SecurityContextDeny` admission plugin, deprecated since v1.27. The Pod Security Admission plugin, available since v1.25, is recommended instead. See https://kubernetes.io/docs/reference/access-authn-authz/admission-controllers/#securitycontextdeny for more information.
+Removed the `SecurityContextDeny` admission plugin, deprecated since v1.27.
+The [Pod Security Admission](https://k8s.io/docs/concepts/security/pod-security-admission/) plugin,
+available since v1.25, is recommended instead.

We can't link to the (removed) docs for a removed admission controller.

Thanks, I updated that!