备份系统原 yum 源

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

替换 yum 源

• 华为 yum 源

# wget -O /etc/yum.repos.d/CentOS-Base.repo https://repo.huaweicloud.com/repository/conf/CentOS-7-reg.repo

• 阿里 yum 源

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

• 网易163 yum 源

#  wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo

替换 EPEL 源 - 可选

• 华为 EPEL 源

# wget -O /etc/yum.repos.d/epel.repo https://file.cnxiaobai.com/Linux/Yum/epel.repo

• 阿里 EPEL 源

# wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo

清理缓存

# yum clean all

生成新的缓存

# yum makecache

更新系统

# yum -y update