CentOS的yum在安装时默认是将/etc/yum.repos.d/目录下.repo后缀文件都查找，然后用找到的第一个源。
如果安装有网络的源和光盘cdrom的源，在列表中CentOS-Base.repo被先找到，这里是网络源。那么光盘就不会在被安装。
可以设置文件优先级来让yum先搜索优先级高的，我们设置CentOS-Media.repo文件高，CentOS-Base.repo次之。
安装yum-priorities 来管理优先级
[root@Cent0S7 ]yum -y install yum-priorities
文件优先级设置，priority=N # N值为1-99，数字越大,优先级越低.（如果repo文件项里不写priority那默认是99，最低。）
注意:priority=1这个要放到repo文件的项里,和enabled一样;而不是一个repo文件里放一个priority=1,另一个文件放priority=2就是priority=1文件优先级高了.
以 163.repo和aliyun.repo文件做例子,在[base_aliyun]项下和[base_163]分别放了priority代表，当使用到base里的链接时，优先使用[base_aliyun]项下地址。
其他项也是一样，当然如果有些链接报错感觉没用，直接在项下加入 enabled=0 关闭此项即可。
[root@Cent0S7 ~]# vi /etc/yum.repos.d/aliyun.repo
[base_aliyun]
name=CentOS-$releasever - Base - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/os/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/os/$basearch/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/os/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
priority=1
[updates_aliyun]
name=CentOS-$releasever - Updates - mirrors.aliyun.com
failovermethod=priority
baseurl=http://mirrors.aliyun.com/centos/$releasever/updates/$basearch/
http://mirrors.aliyuncs.com/centos/$releasever/updates/$basearch/
http://mirrors.cloud.aliyuncs.com/centos/$releasever/updates/$basearch/
gpgcheck=1
gpgkey=http://mirrors.aliyun.com/centos/RPM-GPG-KEY-CentOS-7
#additional packages that may be useful
[root@Cent0S7 ~]# vi /etc/yum.repos.d/163.repo
[base_163] name=CentOS-$releasever - Base - 163.com #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os baseurl=http://mirrors.163.com/centos/$releasever/os/$basearch/ gpgcheck=1 gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7 priority=2 [updates_163] name=CentOS-$releasever - Updates - 163.com #mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo =updates baseurl=http://mirrors.163.com/centos/$releasever/updates/$basearch/ gpgcheck=1 gpgkey=http://mirrors.163.com/centos/RPM-GPG-KEY-CentOS-7
启用CentOS-Media 这个光盘源
[root@Cent0S7 ~]# sed -i 's/enabled=0/enabled=1/g' /etc/yum.repos.d/CentOS-Media.repo
安装httpd来测试：
网络和光盘Iso都设置好，没有设置优先级：
可以看到 Repository里是base也就是网络的源。
[root@Cent0S7 yum.repos.d]# yum install httpd Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * c7-media: * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com Resolving Dependencies --> Running transaction check
---- 中间略 ---- Dependencies Resolved ===================================================================================================================== Package Arch Version Repository Size ===================================================================================================================== Installing: httpd x86_64 2.4.6-97.el7.centos updates 2.7 M Installing for dependencies: apr x86_64 1.4.8-7.el7 base 104 k apr-util x86_64 1.5.2-6.el7 base 92 k httpd-tools x86_64 2.4.6-97.el7.centos updates 93 k mailcap noarch 2.1.41-2.el7 base 31 k Transaction Summary ===================================================================================================================== Install 1 Package (+4 Dependent packages) Total download size: 3.0 M Installed size: 10 M Is this ok [y/d/N]:
设置优先级后：
可以看到先搜索c7-media 也就是光盘里 c7-media是repo文件里设置的name可以随意改。
[root@Cent0S7 yum.repos.d]# yum install httpd Loaded plugins: fastestmirror, priorities Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * c7-media: * extras: mirrors.aliyun.com * updates: mirrors.aliyun.com 10867 packages excluded due to repository priority protections Resolving Dependencies --> Running transaction check
---- 中间略 ---- Dependencies Resolved ===================================================================================================================== Package Arch Version Repository Size ===================================================================================================================== Installing: httpd x86_64 2.4.6-93.el7.centos c7-media 2.7 M Installing for dependencies: apr x86_64 1.4.8-5.el7 c7-media 103 k apr-util x86_64 1.5.2-6.el7 c7-media 92 k httpd-tools x86_64 2.4.6-93.el7.centos c7-media 92 k mailcap noarch 2.1.41-2.el7 c7-media 31 k Transaction Summary ===================================================================================================================== Install 1 Package (+4 Dependent packages) Total download size: 3.0 M Installed size: 10 M Is this ok [y/d/N]:
查看列表
[root@Cent0S7 ]# yum repolist
统计安装包个数
[root@Cent0S7 ]# yum list | wc -l 10498
脚本安装：
[root@Cent0S7 ]# cat <<EOF | sudo tee yum-localrepo.sh #! /bin/bash mkdir -p /media/cdrom/ mount /dev/cdrom /media/cdrom/ echo "/dev/cdrom /mnt/cdrom iso9660 defaults 0 0" >> /etc/fstab sed -i 's/enabled=0/enabled=1/g' /etc/yum.repos.d/CentOS-Media.repo echo "priority=1" >> /etc/yum.repos.d/CentOS-Media.repo echo "priority=2" >> /etc/yum.repos.d/CentOS-Base.repo yum -y install yum-priorities yum makecache EOF
执行脚本：
[root@CentOs7]# sh yum-localrepo.sh
参考：
http://cnblogs.com/mountain2011/p/10224350.html
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