Kubernetes dashboard through kubectl proxy - port confusion - kubernetes

Question

I have seen that the standard way to access http services through the kubectl proxy is the following:
http://api.host/api/v1/namespaces/NAMESPACE/services/SERVICE_NAME:SERVICE_PORT/proxy/
Why is it that the kubernetes-dashboard uses https:kubernetes-dashboard: for SERVICE_NAME:SERVICE_PORT?
I would assume from the following that it would be kubernetes_dashboard:443.
kubectl -n kube-system get service kubernetes-dashboard -o wide
NAME TYPE CLUSTER-IP EXTERNAL-IP PORT(S) AGE SELECTOR
kubernetes-dashboard ClusterIP 10.233.50.212 <none> 443:31663/TCP 15d k8s-app=kubernetes-dashboard
Additionally, what is the meaning of the port show 443:31663 when all other services will just have x/TCP (x being one number instead of x:y)
Lastly, kubectl cluster-info will show
Kubernetes master is running at https://x.x.x.x:x
kubernetes-dashboard is running at https://x.x.x.x:x/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy
I have created a simple service but it does not show here and I am confused how to determine what services show here or not.

Answer 1

Why is it that the kubernetes-dashboard uses
https:kubernetes-dashboard: for SERVICE_NAME:SERVICE_PORT?
Additionally, what is the meaning of the port show 443:31663 when all
other services will just have x/TCP (x being one number instead of
x:y)
As described in Manually constructing apiserver proxy URLs, the default way is
http://kubernetes_master_address/api/v1/namespaces/namespace_name/services/service_name[:port_name]/proxy
By default, the API server proxies to your service using http. To use
https, prefix the service name with https::
http://kubernetes_master_address/api/v1/namespaces/namespace_name/services/https:service_name:[port_name]/proxy
The supported formats for the name segment of the URL are:
<service_name> - proxies to the default or unnamed port using http
<service_name>:<port_name> - proxies to the specified port using http
https:<service_name>: - proxies to the default or unnamed port using https (note the trailing colon)
https:<service_name>:<port_name> - proxies to the specified port using https
Next:
I have created a simple service but it does not show here and I am
confused how to determine what services show here or not.
What is what I found and tested for you:
cluster-info API reference:
Display addresses of the master and services with label kubernetes.io/cluster-service=true To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
So, as soon as you add kubernetes.io/cluster-service: "true" label - the service starts to be seen under kubectl cluster-info.
BUT!! There is an expected behavior when you see that you service disappear from output in couple of minutes. Explanation has been found here - I only copy paste it here for future reference.
The other part is the addon manager. It uses this annotation to
synchronizes the cluster state with static manifest files. The
behavior was something like this:
1) addon manager reads a yaml from disk -> deploys the contents
2) addon manager reads all deployments from api server with annotation cluster-service:true -> deletes all that do not exist as files
As a result, if you add this annotation, addon manager will remove dashboard after a minute or so.
So,
dashboard is deployed after cluster creation -> annotation should not be set:
https://github.com/kubernetes/dashboard/blob/b98d167dadaafb665a28091d1e975cf74eb31c94/src/deploy/kubernetes-dashboard.yaml
dashboard is deployed part of cluster creation -> annotation should be set:
https://github.com/kubernetes/kubernetes/blob/master/cluster/addons/dashboard/dashboard-controller.yaml
At least this was the behavior some time ago. I think kubeadm does not use addon-manager. But it is still part of kube-up script.
Solution for this behavior also exists: add additional label addonmanager.kubernetes.io/mode: EnsureExists
Explanation is here
You final service should look like:
# ------------------- Dashboard Service ------------------- #
kind: Service
apiVersion: v1
metadata:
labels:
k8s-app: kubernetes-dashboard
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: EnsureExists
name: kubernetes-dashboard
namespace: kube-system
spec:
ports:
- port: 443
targetPort: 8443
selector:
k8s-app: kubernetes-dashboard
kubectl get svc kubernetes-dashboard -n kube-system -o yaml
apiVersion: v1
kind: Service
metadata:
annotations:
kubectl.kubernetes.io/last-applied-configuration: |
{"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"addonmanager.kubernetes.io/mode":"EnsureExists","k8s-app":"kubernetes-dashboard","kubernetes.io/cluster-service":"true"},"name":"kubernetes-dashboard","namespace":"kube-system"},"spec":{"ports":[{"port":443,"targetPort":8443}],"selector":{"k8s-app":"kubernetes-dashboard"}}}
labels:
addonmanager.kubernetes.io/mode: EnsureExists
k8s-app: kubernetes-dashboard
kubernetes.io/cluster-service: "true"
kubectl cluster-info
Kubernetes master is running at https://*.*.*.*
...
kubernetes-dashboard is running at https://*.*.*.*/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy
...