centos7运行yum报如下提示：Run "yum repolist all" to see the repos you have

centos7运行yum报如下提示：

There are no enabled repos.
 Run "yum repolist all" to see the repos you have.
 To enable Red Hat Subscription Management repositories:
     subscription-manager repos --enable <repo>
 To enable custom repositories:
     yum-config-manager --enable <repo>

解决办法：

yum -y install yum-utils

如果不能运行先试着更换yum源：

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

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

curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo