Document hidden /logs API

[RichardoC]

Environmental Info:
K3s Version:
$ kubectl version
WARNING: This version information is deprecated and will be replaced with the output from kubectl version --short. Use --output=yaml|json to get the full version.
Client Version: version.Info{Major:"1", Minor:"24", GitVersion:"v1.24.4", GitCommit:"95ee5ab382d64cfe6c28967f36b53970b8374491", GitTreeState:"clean", BuildDate:"2022-08-17T18:54:23Z", GoVersion:"go1.18.5", Compiler:"gc", Platform:"linux/amd64"}
Kustomize Version: v4.5.4
Server Version: version.Info{Major:"1", Minor:"24", GitVersion:"v1.24.8+k3s1", GitCommit:"648004e4faeaf9e8705386342e95ec9bd211c2b8", GitTreeState:"clean", BuildDate:"2022-11-18T18:29:47Z", GoVersion:"go1.18.8", Compiler:"gc", Platform:"linux/amd64"}

Thanks,

Node(s) CPU architecture, OS, and Version:
Rancher Desktop

Version info

$ rdctl version
rdctl client version: 1.1.0, targeting server version: v0

Rancher Desktop version 1.7.0 on Ubuntu 22.04.1 x64

Cluster Configuration:
N/A

Describe the bug:
Originally reported as rancher-sandbox/docs.rancherdesktop.io#136
While experimenting with the following command, I spotted an API that's not present in upstream Kubernetes, which doesn't conform to their schema standards (it's non-json)

$ kubectl get --raw / | grep logs
"/logs",

$ kubectl get --raw /logs

acpid.log
buildkitd.log
cloud-init-output.log
containerd.log
containers/
dmesg
lima-init.log
messages
openresty/
pods/
rancher-desktop-guestagent.log
wtmp

This should be documented, and preferably be json to conform to the other APIs exposed.

Steps To Reproduce:
$ kubectl get --raw /logs

Expected behavior:
This would be documented, and return a json file rather than html

Actual behavior:
Returns an html page of files

Additional context / logs:

[brandond]

That's not something we add. I see that someone pointed you here from the RD repo, but I think they were mistaken. The few routes that K3s adds to the apiserver port are all listed at https://github.com/k3s-io/k3s/blob/master/pkg/server/router.go#L41. Except for /static, /cacerts, and /ping, they are all prefixed with /v1-k3s/.

[brandond]

Copying my response from the other issue:

Yes, this is a core Kubernetes thing:
https://github.com/kubernetes/kubernetes/blob/v1.25.5/pkg/routes/logs.go#L32-L42
https://github.com/kubernetes/kubernetes/blob/v1.25.5/pkg/controlplane/instance.go#L342-L344
https://github.com/kubernetes/kubernetes/blob/v1.25.5/cmd/kube-apiserver/app/options/options.go#L113
https://github.com/kubernetes/kubernetes/blob/v1.25.5/cmd/kube-apiserver/app/options/options.go#L173-L175

Despite being listed as slated for removal it appears to still be there, and enabled by default.

You can start K3s with --kube-apiserver-arg=enable-logs-handler=false if you want to turn it off.