运行kubeadm upgrade plan
时我得到:
[preflight] Running pre-flight checks.
[upgrade] Making sure the cluster is healthy:
[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'
[upgrade/config] FATAL: unexpected error when reading kubeadm-config ConfigMap: ClusterConfiguration key value pair missing
这个 configmap 是什么,我如何获得它?