yum 问题

[root@localhost ~]# yum update
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>

出现以上报错，卸载重新安装

rpm -qa|grep yum #查看yum

rpm -e yum-plugin-fastestmirror-1.1.31-34.el7.noarch --nodeps
rpm -e yum-metadata-parser-1.1.4-10.el7.x86_64 --nodeps
rpm -e yum-3.4.3-132.el7.centos.0.1.noarch --nodeps #卸载

wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-plugin-fastestmirror-1.1.31-34.el7.noarch.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-metadata-parser-1.1.4-10.el7.x86_64.rpm
wget http://vault.centos.org/7.2.1511/os/x86_64/Packages/yum-3.4.3-132.el7.centos.0.1.noarch.rpm #下载对应包，可以去官网下载对应版本包（http://vault.centos.org/）

rpm -ivh yum-* #安装

最后下载你想要的源，就可以