K8S 使用的 DNS 是 Core DNS，可以在这里添加新的域名、IP

kubectl get cm -n kube-system
NAME                                 DATA   AGE
coredns                              2      33d
extension-apiserver-authentication   6      33d
kube-proxy                           2      33d
kubeadm-config                       2      33d
kubelet-config-1.16                  1      33d

kubectl edit cm coredns -n kube-system

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
        }
        hosts {
           	172.16.3.203 	registry.linjb.com
			172.16.3.203 	minio.linjb.com
			172.16.3.203    gitlab.linjb.com

           fallthrough
        }
        prometheus :9153
        forward . /etc/resolv.conf
        cache 30
        reload
        loadbalance
    }