报错信息：
KubeControllerManager has disappeared from Prometheus target discovery.
集群版本：

• k8s 1.18
• kube-prometheusr elease1.6
• docker 19.3

根据ServiceMonitor—> Service—>endpoints(pod) 服务发现机制查看到KubeControllerManager没有对应的svc 所以我们需要创建svc，配置文件如下：

kind: Service
apiVersion: v1
metadata:
  name: kube-controller-manager
  labels:
    k8s-app: kube-controller-manager
  namespace: kube-system
spec:
  clusterIP: None
  ports:
    - protocol: TCP
      port: 10257
      targetPort: 10257
      name: https-metrics
  selector:
    component: kube-controller-manager

重新apply下配置文件，查看prometheusr target即可

prometheusr 如果显示targetDown的话，修改配置文件/etc/kubernetes/manifests/kube-controller-manager.yaml 相关字段，保存自动重启，集群的话主节点都要修改

- --bind-address=0.0.0.0