更换本地的yum源为阿里云提供的镜像

阿里云提供的yum镜像地址为：http://mirrors.aliyun.com/

Mirror	Last update	Help
CPAN	2016-03-31 15:49:25
CRAN	2016-05-07 04:39:28
CTAN	2016-05-07 04:11:50
apache	2016-05-07 01:23:34
archlinux	2016-05-07 16:56:19	help
centos	2016-05-07 02:50:21	help
ceph	2016-05-07 03:15:51	help
cygwin	2016-05-07 09:01:43	help
debian	2016-05-07 16:06:24	help
debian-backports	2016-05-07 16:50:04	help
debian-cd	2016-05-04 01:05:05
debian-security	2016-05-07 16:30:13	help
deepin	2016-05-07 03:00:08	help
docker-engine	2016-05-07 02:05:05	help
docker-toolbox	2016-05-07 03:00:04	help
dotdeb	2016-05-07 00:05:36	help
epel	2016-05-07 14:26:46	help
fedora	2016-05-07 02:57:58	help
freebsd	2016-05-06 23:29:36	help
gentoo	2016-05-07 00:43:20	help
gentoo-portage	2016-05-07 04:00:55	help
gentoo-portage-prefix	2015-01-28 06:09:50
kali	2016-05-07 02:19:28
kali-security	2015-06-26 02:22:01
linux-kernel	2016-05-07 04:00:41
macports	2016-05-06 03:03:19
mariadb	2016-05-07 15:30:30
mongodb	2016-05-07 02:36:46
oldubuntu-releases	2016-05-07 02:30:07
opensuse	2016-05-07 13:29:16	help
packman	2016-05-07 02:20:09	help
pypi	2016-05-07 02:57:07	help
raspbian	2016-05-07 03:16:21	help
rpmfusion	2016-05-07 04:01:39
rubygems	2016-05-07 03:21:58	help
sabayonlinux	2016-05-07 01:30:07
scientificlinux	2016-05-07 12:21:28	help
ubuntu	2016-05-07 19:01:04	help
ubuntu-releases	2016-05-07 02:24:30
zabbix	2016-05-07 02:40:20

找到自己的使用系统，点击help，可以查看更换说明，以centos为例：http://mirrors.aliyun.com/help/centos

1、备份

mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup

2、下载新的CentOS-Base.repo 到/etc/yum.repos.d/

CentOS 5

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-5.repo

CentOS 6

wget -O /etc/yum.repos.d/CentOS-Base.repo http://mirrors.aliyun.com/repo/Centos-6.repo

CentOS 7

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

3、之后运行yum makecache生成缓存