来自服务器的错误（ServiceUnavailable）：服务器当前无法处理请求（获取nodes.metrics.k8s.io）

Question

运行“kubectl topnodes”时出现错误：

来自服务器的错误（ServiceUnavailable）：服务器当前无法处理请求（获取nodes.metrics.k8s.io）

k8s version:
kubectl version
Client Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.1", GitCommit:"eec55b9ba98609a46fee712359c7b5b365bdd920", GitTreeState:"clean", BuildDate:"2018-12-13T10:39:04Z", GoVersion:"go1.11.2", Compiler:"gc", Platform:"linux/amd64"}
Server Version: version.Info{Major:"1", Minor:"13", GitVersion:"v1.13.1", GitCommit:"eec55b9ba98609a46fee712359c7b5b365bdd920", GitTreeState:"clean", BuildDate:"2018-12-13T10:31:33Z", GoVersion:"go1.11.2", Compiler:"gc", Platform:"linux/amd64"}

[root@manager ~]# kubectl api-versions
admissionregistration.k8s.io/v1beta1
apiextensions.k8s.io/v1beta1
apiregistration.k8s.io/v1
apiregistration.k8s.io/v1beta1
apps/v1
apps/v1beta1
apps/v1beta2
authentication.k8s.io/v1
authentication.k8s.io/v1beta1
authorization.k8s.io/v1
authorization.k8s.io/v1beta1
autoscaling/v1
autoscaling/v2beta1
autoscaling/v2beta2
batch/v1
batch/v1beta1
certificates.k8s.io/v1beta1
coordination.k8s.io/v1beta1
events.k8s.io/v1beta1
extensions/v1beta1
metrics.k8s.io/v1beta1
networking.k8s.io/v1
policy/v1beta1
rbac.authorization.k8s.io/v1
rbac.authorization.k8s.io/v1beta1
scheduling.k8s.io/v1beta1
storage.k8s.io/v1
storage.k8s.io/v1beta1
v1

[root@manager ~]# kubectl get po --all-namespaces

NAMESPACE     NAME                                    READY   STATUS    RESTARTS   AGE
kube-system   coredns-86c58d9df4-km7jc                1/1     Running   0          2d21h
kube-system   coredns-86c58d9df4-vltm9                1/1     Running   0          2d21h
kube-system   etcd-manager                            1/1     Running   0          2d23h
kube-system   kube-apiserver-manager                  1/1     Running   0          5h47m
kube-system   kube-controller-manager-manager         1/1     Running   1          2d23h
kube-system   kube-flannel-ds-amd64-5g8w8             1/1     Running   0          2d23h
kube-system   kube-flannel-ds-amd64-69lcm             1/1     Running   0          2d23h
kube-system   kube-flannel-ds-amd64-9hx2f             1/1     Running   0          2d23h
kube-system   kube-proxy-9s6zm                        1/1     Running   0          2d23h
kube-system   kube-proxy-k4qwz                        1/1     Running   0          2d23h
kube-system   kube-proxy-wnzgd                        1/1     Running   0          2d23h
kube-system   kube-scheduler-manager                  1/1     Running   1          2d23h
kube-system   kubernetes-dashboard-79ff88449c-7fpw6   1/1     Running   0          2d23h
kube-system   metrics-server-68d85f76bb-pj8bs         1/1     Running   0          111m
kube-system   tiller-deploy-5478b6c547-bf82v          1/1     Running   0          4h7m

[root@manager ~]# kubectl logs -f -n kube-system metrics-server-68d85f76bb-pj8bs

I1217 06:42:43.451782       1 serving.go:273] Generated self-signed cert (apiserver.local.config/certificates/apiserver.crt, apiserver.local.config/certificates/apiserver.key)
[restful] 2018/12/17 06:42:44 log.go:33: [restful/swagger] listing is available at https://:443/swaggerapi
[restful] 2018/12/17 06:42:44 log.go:33: [restful/swagger] https://:443/swaggerui/ is mapped to folder /swagger-ui/
I1217 06:42:44.099720       1 serve.go:96] Serving securely on [::]:443

并且没有系统错误日志。我该如何解决这个问题？

操作系统是：CentOS Linux 版本 7.5.1804（核心）

Answer 1

我已经解决了这个问题，添加hostNetwork: true到metries-server.yaml：

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    k8s-app: metrics-server
  name: metrics-server
  namespace: kube-system
spec:
  selector:
    matchLabels:
      k8s-app: metrics-server
  strategy:
    rollingUpdate:
      maxUnavailable: 0
  template:
    metadata:
      labels:
        k8s-app: metrics-server
    spec:
      hostNetwork: true ## add

文档：

[root@xx yaml]# kubectl explain deployment.spec.template.spec.hostNetwork
KIND:     Deployment
VERSION:  apps/v1

FIELD:    hostNetwork <boolean>

DESCRIPTION:
     Host networking requested for this pod. Use the host's network namespace.
     If this option is set, the ports that will be used must be specified.
     Default to false.

背景：
成功运行测量，但kubectl top nodes占用：Error from server (ServiceUnavailable): the server is currently unable to handle the request (get nodes.metrics.k8s.io)。