1.首先备份yum
1 /ect/yum.repos.d/CentOS-Base.repo 2 mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
2.替换yum源
替换为阿里源
1 wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
3.生成缓存
1 yum makecache
4.更新系统
1 yum -y update
ps:如果yum正在运行,要先关掉进程 rm -f /var/run/yum.pid