k8s pod之间DNS解析问题:Temporary failure in name resolution
1.ubuntu 系统重启， k8s 网关需要
# 允许所有数据包通过
iptables -P FORWARD ACCEPT
2.查看coredns是否正常
kubectl get po -n kube-system | grep coredns
kubectl get service -n kube-system | grep kube-dns
kubectl get endpoints kube-dns -n kube-system