kubernetes: Ephemeral container fails to be created for Static Pod

What happened?

I created an ephemeral container for a Static Pod using the kubectl debug command. The command succeed.

❯ kubectl debug --image=busybox --share-processes=true --target=kube-apiserver -n kube-system kube-apiserver-kind-control-plane -- sleep infinity
Targeting container "kube-apiserver". If you don't see processes from this container it may be because the container runtime doesn't support this feature.
Defaulting debug container name to debugger-vgkn4.

The API server accepted the ephemeral container:

❯ kubectl -n kube-system get pod kube-apiserver-kind-control-plane --output=jsonpath='{.spec.ephemeralContainers}'
[{"command":["sleep","infinity"],"image":"busybox","imagePullPolicy":"Always","name":"debugger-vgkn4","resources":{},"targetContainerName":"kube-apiserver","terminationMessagePath":"/dev/termination-log","terminationMessagePolicy":"File"}]

However, the container is not created.

Its status is also not available:

❯ kubectl -n kube-system get pod kube-apiserver-kind-control-plane --output=jsonpath='{.status.ephemeralContainerStatuses}'

What did you expect to happen?

I expected one of these:

(a) the API server rejects the request to create an ephemeral container for a Static Pod (b) kubelet creates the ephemeral container, and update the Static Pod’s status sub-resource

How can we reproduce it (as minimally and precisely as possible)?

Using a recent version of docker engine, kind v0.17 or newer, and kubectl v1.25.0 or newer, create a cluster and create an ephemeral container running sleep infinity. Since the ephemeral container is not running, the output of grep is 0.

kind create cluster
kubectl debug --image=busybox --share-processes=true --target=kube-apiserver -n kube-system kube-apiserver-kind-control-plane -- sleep infinity
docker exec -it kind-control-plane ps -axw | grep --count "sleep infinity"

Anything else we need to know?

The Ephemeral Containers KEP does not address Static Pods.

Kubernetes version

$ kubectl version --short
Client Version: v1.25.3
Kustomize Version: v4.5.7
Server Version: v1.25.3

Cloud provider

OS version

# On Linux:
$ cat /etc/os-release
# paste output here
$ uname -a
# paste output here

# On Windows:
C:\> wmic os get Caption, Version, BuildNumber, OSArchitecture
# paste output here

Install tools

Container runtime (CRI) and version (if applicable)

Related plugins (CNI, CSI, …) and versions (if applicable)