Centos6配置国内源
切换yum源
备份原有YUM源配置, 在配置新的YUM源之前，先备份原有的YUM源配置文件：
sudo mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak
创建新的YUM源配置文件, 创建新的YUM源配置文件 CentOS-Base.repo：
sudo touch /etc/yum.repos.d/CentOS-Base.repo
sudo nano /etc/yum.repos.d/CentOS-Base.repo
添加YUM源配置内容, 在新文件中添加以下内容（以清华大学开源镜像站为例）：
[base]
name=CentOS-6.10 - Base
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/6.10/os/$basearch/
gpgcheck=1
gpgkey=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/RPM-GPG-KEY-CentOS-6
[updates]
name=CentOS-6.10 - Updates
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/6.10/updates/$basearch/
gpgcheck=1
gpgkey=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/RPM-GPG-KEY-CentOS-6
[extras]
name=CentOS-6.10 - Extras
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/6.10/extras/$basearch/
gpgcheck=1
gpgkey=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/RPM-GPG-KEY-CentOS-6
[centosplus]
name=CentOS-6.10 - Plus
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/6.10/centosplus/$basearch/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/RPM-GPG-KEY-CentOS-6
[contrib]
name=CentOS-6.10 - Contrib
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/6.10/contrib/$basearch/
gpgcheck=1
enabled=0
gpgkey=https://mirrors.tuna.tsinghua.edu.cn/centos-vault/RPM-GPG-KEY-CentOS-6
更新YUM缓存, 保存配置文件后，执行以下命令更新YUM缓存：
sudo yum clean all
sudo yum makecache
切换epel源
创建新的YUM源配置文件 epel.repo：
sudo touch /etc/yum.repos.d/epel.repo
sudo nano /etc/yum.repos.d/epel.repo
在新文件中添加以下内容：
[epel]
name=Extra Packages for Enterprise Linux 6 - $basearch
enabled=1
failovermethod=priority
baseurl=http://mirrors.cloud.aliyuncs.com/epel-archive/6/$basearch
gpgcheck=0
gpgkey=http://mirrors.cloud.aliyuncs.com/epel-archive/RPM-GPG-KEY-EPEL-6
保存配置文件后，执行以下命令：
yum repolist
执行yum repolist命令，若成功列出仓库列表而没有报404错误，表示切换成功。