Centos7-Yum-使用光盘作为Yum源及变更阿里云为yum源

YUM源为本地光盘:

挂载光盘
# mkdir /mnt/centos/
# mount -t iso 9660 /dev/cdrom /mnt/cdrom/  //光驱设备
# mount -o loop /usr/local/centos-7-x86_64.iso /mnt/cdrom

变更yum文件
# vim /etc/yum.repos.d/CentOS-CD.repo
baseurl=file:///mnt/cdrom/
enable=1

若需要关闭网络YUM源则
#  mv CentOS-Base.repo CentOS-Base.repo.bak 

若需要设置开机挂载
# vim /etc/rc.local (开机启动时，会执行该文件内的操作)
mount -t iso 9660 /dev/cdrom /mnt/cdrom/  任意一条
mount -o loop /usr/local/centos-7-x86_64.iso /mnt/cdrom 任意一条

YUM源变更为阿里云:

方法一:下载相关repo文件

# cd /etc/yum.repo.d
# mv CentOS-Base.repo CentOS-Base.repo.bak
# wget http://mirrors.aliyun.com/repo/Centos-7.repo
# mv Centos-7.repo CentOS-Base.repo
# yum clean all
# yum maecache
# yum -C search 包名