k8s 1.20.2 coredns解析问题

环境

操作系统及内核版本

[root@controller opt]# cat /etc/redhat-release 
CentOS Linux release 7.6.1810 (Core)   
[root@controller opt]# uname -a
Linux controller 3.10.0-957.27.2.el7.x86_64 #1 SMP Mon Jul 29 17:46:05 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux

docker版本

[root@controller opt]# docker version
Client: Docker Engine - Community
 Version:           20.10.2
 API version:       1.41
 Go version:        go1.