问题现象：

k8s 执行 delete操作发现pod一直处于terminating

问题排查

执行：kubectl get APIService
发现：

v1beta1.events.k8s.io           Local        True                        13d
v1beta1.extensions              Local        True                        13d
v1beta1.metrics.k8s.io     kube-system/metrics-server  False (EndpointsNotFound)   71s

有个新增的APIService 处于不正常状态，然后删除重建问题依旧，查看报错：

kubectl describe APIService 

v1beta1.metrics.k8s.io 
Name:         v1beta1.metrics.k8s.io
Namespace:    
Labels:       <none>
Annotations:  <none>
API Version:  apiregistration.k8s.io/v1
Kind:         APIService
Metadata:
  Creation Timestamp:  2021-10-11T03:01:28Z
  Resource Version:    4057041
  Self Link:           /apis/apiregistration.k8s.io/v1/apiservices/v1beta1.metrics.k8s.io
  UID:                 805aac80-69b7-4c41-bd00-b7e72f1f5fcb
Spec:
  Group:                     metrics.k8s.io
  Group Priority Minimum:    100
  Insecure Skip TLS Verify:  true
  Service:
    Name:            metrics-server
    Namespace:       kube-system
    Port:            443
  Version:           v1beta1
  Version Priority:  100
Status:
  Conditions:
    Last Transition Time:  2021-10-11T03:01:28Z
    Message:               cannot find endpoints for service/metrics-server in "kube-system"
    Reason:                EndpointsNotFound
    Status:                False
    Type:                  Available
Events:                    <none>

原因：
cannot find endpoints for service/metrics-server in "kube-system"
查看下集群中的endpoints：
执行：
kubectl get endpoints

elasticsearch-logging     10.244.1.7:9300,10.244.1.8:9300,10.244.1.7:9200 + 1 more...   13d
kube-controller-manager   <none>                                                        13d
kube-dns                  10.244.0.6:53,10.244.3.5:53,10.244.0.6:9153 + 3 more...       13d
kube-scheduler            <none>                                                        13d
node-exporter             10.244.0.4:9100,10.244.1.6:9100,10.244.2.2:9100 + 5 more...   13d

这里没有发现service/metrics-server，说明service和pod的关联出现了问题：
查看下service

apiVersion: v1
kind: Service
metadata:
  name: metrics-server
  namespace: kube-system
spec:
  ports:
  - name: https
    port: 443
    protocol: TCP
    targetPort: https

居然没有selector 这就是问题所在service根本没有跟pod进行绑定：
最终修改service.yaml重新部署

apiVersion: v1
kind: Service
metadata:
  name: metrics-server
  namespace: kube-system
spec:
  ports:
  - name: https
    port: 443
    protocol: TCP
    targetPort: https
  selector:
    app: metric-server

然后查看下endpoints：

kubectl  get endpoints -n kube-system 
NAME                      ENDPOINTS                                                     AGE
elasticsearch-logging     10.244.1.7:9300,10.244.1.8:9300,10.244.1.7:9200 + 1 more...   13d
kube-controller-manager   <none>                                                        13d
kube-dns                  10.244.0.6:53,10.244.3.5:53,10.244.0.6:9153 + 3 more...       13d
kube-scheduler            <none>                                                        13d
metrics-server            10.244.6.10:443                                               13s
node-exporter             10.244.0.4:9100,10.244.1.6:9100,10.244.2.2:9100 + 5 more...   13d

已经发现了metrics-server 问题结局。

问题原因：

主要是APIService不正常导致一直在处在状态APIService执行不下去，最终排查到是metrics-server 中的service绑定异常导致的。

名词解释：

endpoint是k8s集群中的一个资源对象，存储在etcd中，用来记录一个service对应的所有pod的访问地址。