问kubeadm -错误启动版本'‘不支持

EN

[root@master ~]#kubeadm upgrade plan --v=5
I1113 14:14:31.046080    8368 plan.go:67] [upgrade/plan] verifying health of cluster
I1113 14:14:31.046233    8368 plan.go:68] [upgrade/plan] retrieving configuration from cluster
[upgrade/config] Making sure the configuration is correct:
[upgrade/config] Reading configuration from the cluster...
[upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
I1113 14:14:31.111668    8368 common.go:122] running preflight checks
[preflight] Running pre-flight checks.
I1113 14:14:31.111843    8368 preflight.go:78] validating if there are any unsupported CoreDNS plugins in the Corefile
I1113 14:14:31.143841    8368 preflight.go:103] validating if migration can be done for the current CoreDNS release.
[preflight] Some fatal errors occurred:
    [ERROR CoreDNSUnsupportedPlugins]: start version '' not supported
    [ERROR CoreDNSMigration]: start version '' not supported
[preflight] If you know what you are doing, you can make a check non-fatal with `--ignore-preflight-errors=...`

apiVersion: v1
data:
  Corefile: |
    .:53 {
        errors
        health
        ready
        kubernetes cluster.local in-addr.arpa ip6.arpa {
           pods insecure
           fallthrough in-addr.arpa ip6.arpa
           ttl 30
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        loop
        reload
        loadbalance
    }
kind: ConfigMap
metadata:
  creationTimestamp: "2018-12-15T00:02:45Z"
  name: coredns
  namespace: kube-system
  resourceVersion: "45537229"
  selfLink: /api/v1/namespaces/kube-system/configmaps/coredns
  uid: c01fbb58-fffc-11e8-9a01-005056a31666