集群DNS IP可以查看kubelet服务的配置中查看
下载coredns项目的kubernetes
wget https://github.com/coredns/deployment/archive/master.zip
yum -y install unzip
unzip master.zip
因为项目使用了jq命令，需要安装jq程序
由于jq来源于epel，因此需要安装扩展的yum仓库
rpm -ivh ?http://dl.fedoraproject.org/pub/epel/epel-release-latest-7.noarch.rpm
yum -y install jq
上面下载master.zip解压缩至deployment-master文件夹
cd deployment-master/kubernetes
./deploy.sh -i 10.254.0.2 | kubectl apply -f -
查看日志发现
Sep 11 22:01:05 node210 kube-proxy: E0911 22:01:05.726990 ????860 proxier.go:1451] Failed to delete kube-system/kube-dns:dns endpoint connections, error: error deleting conntrack entries for UDP peer {10.254.0.2, 172.30.17.3}, error: error looking for path of conntrack: exec: "conntrack": executable file not found in $PATH
可以看到缺少conntrack文件
yum -y install conntrack-tools
kubernetes 1.11.2安装配置Core-DNS
原文地址：http://blog.51cto.com/fengwan/2174022