why kubernetes dashboard service return json - kubernetes

Question

I am access my kubernetes dashboard using this url:
https://kubernetes.example.com/api/v1/namespaces/kube-system/services/kubernetes-dashboard/#/workload?namespace=default
what make me confusing is the return content just json string, not the login page. The json content is :
{
"kind": "Service",
"apiVersion": "v1",
"metadata": {
"name": "kubernetes-dashboard",
"namespace": "kube-system",
"selfLink": "/api/v1/namespaces/kube-system/services/kubernetes-dashboard",
"uid": "884240d7-8f3f-41a4-a3a0-a89649545c82",
"resourceVersion": "133822",
"creationTimestamp": "2019-09-21T16:21:19Z",
"labels": {
"addonmanager.kubernetes.io/mode": "Reconcile",
"k8s-app": "kubernetes-dashboard",
"kubernetes.io/cluster-service": "true"
},
"annotations": {
"kubectl.kubernetes.io/last-applied-configuration": "{\"apiVersion\":\"v1\",\"kind\":\"Service\",\"metadata\":{\"annotations\":{},\"labels\":{\"addonmanager.kubernetes.io/mode\":\"Reconcile\",\"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\"},\"type\":\"NodePort\"}}\n"
}
},
"spec": {
"ports": [
{
"protocol": "TCP",
"port": 443,
"targetPort": 8443,
"nodePort": 31085
}
],
"selector": {
"k8s-app": "kubernetes-dashboard"
},
"clusterIP": "10.254.75.193",
"type": "NodePort",
"sessionAffinity": "None",
"externalTrafficPolicy": "Cluster"
},
"status": {
"loadBalancer": {
}
}
}
this is my nginx forward config:
upstream kubernetes{
server 172.19.104.231:8001;
}
this is my kubernetes cluster proxy command:
kubectl proxy --address=0.0.0.0 --port=8001 --accept-hosts='^*$'

Answer 1

You are accessing the Kubernetes API to get the kubernetes-dashboard Service resource manifest. This is the JSON that you get back.
If you want to access the Service, you need to access the Service itself, not the Kubernetes API. You can do this for example with port forwarding:
kubectl port-forward svc/kubernetes-dashboard 8443:443
And then access the Service with:
curl localhost:8443/#/workload?namespace=default

Answer 2

Kubernetes documentation has clearer instructions now on how to deploy and access their dashboard:
https://kubernetes.io/docs/tasks/access-application-cluster/web-ui-dashboard/
I went to 127.0.0.1:8001 at first, and got the API JSON (as per the original question) before noticing the URL given under the kubectl proxy instruction:
http://localhost:8001/api/v1/namespaces/kubernetes-dashboard/services/https:kubernetes-dashboard:/proxy/.