1 备份原始源

[root@localhost ~]# mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

2 下载新的镜像源

• 方法1：wget直接下载
  执行命令：

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

  操作如下：

  [root@localhost yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
  --2018-02-09 05：54：04-- http://mirrors.aliyun.com/repo/Centos-7.repo
  正在解析主机 mirrors.aliyun.com (mirrors.aliyun.com)... 180.101.150.31, 180.101.150.28, 180.101.150.26, ...
  正在连接 mirrors.aliyun.com (mirrors.aliyun.com)|180.101.150.31|:80... 已连接。
  已发出 HTTP 请求，正在等待回应... 200 OK
  长度：2573 (2.5K) [application/octet-stream]
  正在保存至: “/etc/yum.repos.d/CentOS-Base.repo”

  100%[==============================================================================>] 2,573 --.-K/s 用时 0s

  2018-02-09 05：54：05 (281 MB/s) - 已保存 “/etc/yum.repos.d/CentOS-Base.repo” [2573/2573])

• 方法2：curl直接下载
  执行命令：

  curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo
  

  操作如下：

  [root@localhost yum.repos.d]# curl -o /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo% Total    % Received % Xferd  Average Speed   Time    Time     Time  Current                               Dload  Upload   Total   Spent    Left  Speed100  2573  100  2573    0     0   8533      0 --：--：-- --：--：-- --：--：--  8548
  

• 方法3：在CentOS-Base.repo 写入地址

  [root@localhost yum.repos.d]# vi CentOS-Base.repo[base]name=CentOS-$releasever - Base - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/        http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=osgpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#released updates[updates]name=CentOS-$releasever - Updates - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/        http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updatesgpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that may be useful[extras]name=CentOS-$releasever - Extras - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/extras/$basearch/        http://mirrors.aliyuncs.com/centos/$releasever/extras/$basearch/#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extrasgpgcheck=1gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#additional packages that extend functionality of existing packages[centosplus]name=CentOS-$releasever - Plus - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/centosplus/$basearch/        http://mirrors.aliyuncs.com/centos/$releasever/centosplus/$basearch/#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplusgpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7#contrib - packages by Centos Users[contrib]name=CentOS-$releasever - Contrib - mirrors.aliyun.comfailovermethod=prioritybaseurl=http://mirrors.aliyun.com/centos/$releasever/contrib/$basearch/        http://mirrors.aliyuncs.com/centos/$releasever/contrib/$basearch/#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=contribgpgcheck=1enabled=0gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
  

3 更新缓存

[root@localhost yum.repos.d]# yum makecache已加载插件：fastestmirror, langpackshttp://mirrors.aliyuncs.com/centos/7/os/x86_64/repodata/repomd.xml: [Errno 12] Timeout on http://mirrors.aliyuncs.com/centos/7/os/x86_64/repodata/repomd.xml: (28, 'Connection timed out after 30000 milliseconds')正在尝试其它镜像。base                                                     | 3.6 kB  00：00：00extras                                                   | 3.4 kB  00：00：00updates                                                  | 3.4 kB  00：00：00(1/5): extras/7/x86_64/prestodelta                       | 102 kB  00：00：01(2/5): extras/7/x86_64/other_db                          | 108 kB  00：00：00(3/5): extras/7/x86_64/filelists_db                      | 636 kB  00：00：01(4/5): base/7/x86_64/other_db                            | 2.5 MB  00：00：02(5/5): base/7/x86_64/filelists_db                        | 6.7 MB  00：00：02Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com元数据缓存已建立