检查yum仓库
查看 所有repo文件
ll /etc/yum.repos.d/
检查所有仓库状态
yum repolist all |grep enable
安装epel源
查看系统中的epel包
yum list all | grep epel-release.noarch
安装epel-release.noarch包，配置epel源。
yum install -y epel-release
vi /etc/yum.repos.d/epel.repo
#中科大的epel源---建议
[epel-USTC]
name=epel-USTC--CentOS-$releasever
baseurl=https://mirrors.ustc.edu.cn/epel/$releasever/Everything/$basearch/
enabled=1
gpgcheck=0
# 华为云的epel源
[epel-huaweicloud]
name=epel-huaweicloud-CentOS-$releasever
baseurl=https://mirrors.huaweicloud.com/epel/$releasever/Everything/$basearch/
gpgcheck=0
# 清华的epel源
[epel-tsinghua]
name=Extra Packages-tsinghua for Enterprise Linux $releasever - $basearch
baseurl=https://mirrors.tuna.tsinghua.edu.cn/epel/$releasever/Everything/$basearch
enabled=1
gpgcheck=0
source /etc/yum.repos.d/epel.repo
yum install httpd -y // 检查配置结果