centos7配置yum源、epel源为国内镜像

缺省yum源的服务器通常在国外，安装时速度比较慢。为了提高安装rpm包的速度，可以将yum源配置为国内的阿里repo。

1、先备份系统原有的repo

[root@localhost ~]#cd /etc/yum.repos.d/

[root@localhost yum.repos.d]#ls

CentOS-Base.repo CentOS-Debuginfo.repo CentOS-Media.repo CentOS-Vault.repo webtatic-archive.repo webtatic-testing.repo
CentOS-CR.repo CentOS-fasttrack.repo CentOS-Sources.repo epel.repo

[root@localhost yum.repos.d]#mkdir backup

[root@localhost yum.repos.d]# mv * ./backup/

2、获取阿里centos7的base-repo

[root@localhost yum.repos.d]# wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-7.repo

[root@localhost yum.repos.d]# ls
backup CentOS-Base.repo

3、清除并重新生成yum cache

[root@localhost yum.repos.d]# yum clean all

[root@localhost yum.repos.d]# yum makecache

4、测试一下新的yum源是否可用

[root@localhost yum.repos.d]# yum install -y screen
Loaded plugins: fastestmirror, langpacks
Loading mirror speeds from cached hostfile
* base: mirrors.aliyun.com
* extras: mirrors.aliyun.com
* updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package screen.x86_64 0:4.1.0-0.25.20120314git3c2946.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

==================================================================================================================================================
Package                     Arch                        Version                                                  Repository                 Size
==================================================================================================================================================
Installing:
screen                      x86_64                      4.1.0-0.25.20120314git3c2946.el7                         base                      552 k

Transaction Summary
==================================================================================================================================================
Install 1 Package

Total download size: 552 k
Installed size: 914 k
Downloading packages:
screen-4.1.0-0.25.20120314git3c2946.el7.x86_64.rpm                                                                         | 552 kB 00:00:00
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : screen-4.1.0-0.25.20120314git3c2946.el7.x86_64                                                                                 1/1
Verifying : screen-4.1.0-0.25.20120314git3c2946.el7.x86_64                                                                                 1/1

Installed:
screen.x86_64 0:4.1.0-0.25.20120314git3c2946.el7

Complete!