自建yum仓库，分别为网络源和本地源

配置本地源####

1. 建立本地源目录
   [root@qingcheng-db lgp]#mkdir /mnt/cdrom
   [root@qingcheng-db lgp]#mkdir /yum

2. 挂载Centos光盘
   [root@qingcheng-db lgp]#mount /dev/cdrom /mnt/cdrom
   [root@qingcheng-db lgp]#cp -r /mnt/cdrom/* /yum

3. 备份repo
   [root@qingcheng-db lgp]#cd /etc/yum.repo.d/
   [root@qingcheng-db lgp]#mkdir backup
   [root@qingcheng-db lgp]#mv CentOS-Base.repo CentOS-CR.repo CentOS-Vault.repo CentOS-Vault.repo ./backup

4. 编辑Centos-Media.repo
   [root@qingcheng-db lgp]#vim Centos-Media.repo

[base]
name=Centos
baseurl=file:///yum
enable=1
gpgckeck=0
gpgkey=file:///mnt/cdrom/RPM-GPG-KEY-CentOS-7

5. 清除yum缓存
   [root@qingcheng-db lgp]#yum clean all

配置网络源####

1. 备份源镜像文件
   [root@qingcheng-db yum.repos.d]# mv centos* ./backup

2. 下载阿里云的镜像到/etc/yum.repos.d/
   [root@qingcheng-db yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo
   http://mirrors.aliyun.com/repo/Centos-7.repo

3. 清除yum缓存
   [root@qingcheng-db yum.repos.d]# yum clean all
   [root@qingcheng-db yum.repos.d]# yum makecache