K8s EndpointSlice demo (with custom controller case)

endpointslice-demo1.log

[centos@kube-master ~]$ cat svc-nginx-k8s.yml 
---
kind: Service
apiVersion: v1
metadata:
  name: k8s-nginx
  labels:
    endpointslice-controller.k8s.io: multus
spec:
  selector:
    app: k8s-nginx
  ports:
  - protocol: TCP
    port: 80
---
apiVersion: apps/v1
kind: Deployment
metadata:
  name: k8s-nginx
spec:
  selector:
    matchLabels:
      app: k8s-nginx
  replicas: 1
  template:
    metadata:
      labels:
        app: k8s-nginx
    spec:
      containers:
      - name: k8s-nginx
        image: nginx
        ports:
        - containerPort: 80
        imagePullPolicy: IfNotPresent
[centos@kube-master ~]$ kubectl create -f svc-nginx-k8s.yml
service/k8s-nginx created
deployment.apps/k8s-nginx created
[centos@kube-master ~]$ kubectl get svc
NAME         TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)   AGE
k8s-nginx    ClusterIP   10.104.101.10   <none>        80/TCP    10s
kubernetes   ClusterIP   10.96.0.1       <none>        443/TCP   39h
[centos@kube-master ~]$ kubectl get endpointslices.discovery.k8s.io --show-labels
NAME              ADDRESSTYPE   PORTS   ENDPOINTS        AGE   LABELS
k8s-nginx-7lrfc   IPv4          80      10.244.1.9       16s   endpointslice.kubernetes.io/managed-by=endpointslice-controller.k8s.io,kubernetes.io/service-name=k8s-nginx
kubernetes        IPv4          6443    192.168.122.76   39h   kubernetes.io/service-name=kubernetes
### Change the endpointslice labels ('endpointslice.kubernetes.io/managed-by': 'endpointslice-controller.k8s.io' -> 'customcontroller-1')
[centos@kube-master ~]$ kubectl patch endpointslices.discovery.k8s.io/k8s-nginx-7lrfc -p '{"metadata": {"labels": { "endpointslice.kubernetes.io/managed-by": "customcontroller-1" }}}'
endpointslice.discovery.k8s.io/k8s-nginx-7lrfc patched
[centos@kube-master ~]$ kubectl get endpointslices.discovery.k8s.io --show-labels
NAME              ADDRESSTYPE   PORTS   ENDPOINTS        AGE   LABELS
k8s-nginx-7lrfc   IPv4          80      10.244.1.9       41s   endpointslice.kubernetes.io/managed-by=customcontroller-1,kubernetes.io/service-name=k8s-nginx
kubernetes        IPv4          6443    192.168.122.76   39h   kubernetes.io/service-name=kubernetes
[centos@kube-master ~]$ kubectl scale --replicas=3 deploy/k8s-nginx
deployment.apps/k8s-nginx scaled
### After scale, k8s endpointslice controller creates new endpointslice because k8s endpointslice controller ignores previous by label change.
[centos@kube-master ~]$ kubectl get endpointslices.discovery.k8s.io --show-labels
NAME              ADDRESSTYPE   PORTS   ENDPOINTS                            AGE   LABELS
k8s-nginx-7lrfc   IPv4          80      10.244.1.9                           54s   endpointslice.kubernetes.io/managed-by=customcontroller-1,kubernetes.io/service-name=k8s-nginx
k8s-nginx-9fg6w   IPv4          80      10.244.1.9,10.244.2.11,10.244.1.10   6s    endpointslice.kubernetes.io/managed-by=endpointslice-controller.k8s.io,kubernetes.io/service-name=k8s-nginx
kubernetes        IPv4          6443    192.168.122.76                       39h   kubernetes.io/service-name=kubernetes
[centos@kube-master ~]$