yum安装报错：This system is not registered with an entitlement server. You can use subscription-manager t

Linux在进行yum安装有时候会报错

This system is not registered with an entitlement server. You can use subscription-manager to register.
译：该系统没有在授权服务器上注册。您可以使用订阅管理器进行注册。

楼主是在安装k8s遇到的问题配置好yum源之后报错无法安装。
解决办法：
1.重新配置yum源，并清理掉之前系统的yum配置

2.目录： /etc/yum.repos.d/kubernetes.repo

cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

3.配置成阿里源

wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo

4.问题解决

yum install --setopt=obsoletes=0 kubeadm-1.17.4-0 kubelet-1.17.4-0 kubect11.17.4-0 -y