linux系统安装后自带的bash源由于在国外，安装软件包的时候会非常慢，最好替换一下yum源。
- 关于yum源的简单介绍
yum的主要功能是更方便地添加，删除和更新rpmbao，它能自带解决包的依赖，（rpm包安装有很强的包的依赖性）yum可以同时配置多个源。
- 配置yum信息
查看当前系统使用的源 [root@localhost ~]# yum repolist Loaded plugins: fastestmirror Loading mirror speeds from cached hostfile * base: mirrors.aliyun.com * extras: mirror.bit.edu.cn * updates: mirror.bit.edu.cn repo id repo name status base/7/x86_64 CentOS-7 - Base 9,591 extras/7/x86_64 CentOS-7 - Extras 446 updates/7/x86_64 CentOS-7 - Updates 2,416 repolist: 12,453
由于bash源在国外，有时安装应用会很慢，需要进行yum的修改，国内有安全可靠的yum源如阿里，网易，163等。现在配置阿里的yum源。阿里的yuan源镜像地址为：https://opsx.alibaba.com/mirror，首先下在该镜像站点中的yum，这里选择epel源。
wget https://mirrors.aliyun.com/epel/epel-release-latest-7.noarch.rpm
安装epel源
[root@localhost ~]# rpm -ivh epel-release-latest-7.noarch.rpm warning: epel-release-latest-7.noarch.rpm: Header V3 RSA/SHA256 Signature, key ID 352c64e5: NOKEY Preparing... ################################# [100%] Updating / installing... 1:epel-release-7-11 ################################# [100%]
此时看到epel源已经安装好了，如果我们不适用bash源，可以将bash源修改名称或者移走
mv CentOS-Base.repo CentOS-Base.repo.bak
查看源
1 [root@localhost ~]# yum repolist 2 Loaded plugins: fastestmirror 3 Loading mirror speeds from cached hostfile 4 * epel: mirror01.idc.hinet.net 5 repo id repo name status 6 epel/x86_64 Extra Packages for Enterprise Linux 7 - x86_64 12,449 7 repolist: 12,449
此时已经配置好了epel源，接下来再添加本地源，当没有网络环境的时候可以使用本地源安装一些工具包。
在linux系统中光盘文件为/dev/sr0，通常将该文件挂载在指定目录。下面进行挂载
[root@localhost ~]# mkdir -p /media/cdrom [root@localhost ~]# mount /dev/sr0 /media/cdrom/ mount: /dev/sr0 is write-protected, mounting read-only [root@localhost ~]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/centos-root 9.8G 1.1G 8.2G 12% / devtmpfs 482M 0 482M 0% /dev tmpfs 493M 0 493M 0% /dev/shm tmpfs 493M 6.8M 486M 2% /run tmpfs 493M 0 493M 0% /sys/fs/cgroup /dev/sda1 190M 94M 83M 54% /boot /dev/mapper/centos-data 7.6G 36M 7.2G 1% /data tmpfs 99M 0 99M 0% /run/user/0 /dev/sr0 8.1G 8.1G 0 100% /media/cdrom
挂载上后需要到/etc/yum.repos.d/中修改CentOS-Media.repo中的信息，该源文件本地源配置文件，打开内容如下：
[c7-media] name=CentOS-$releasever - Media baseurl=file:///media/CentOS/ file:///media/cdrom/ file:///media/cdrecorder/ gpgcheck=1 enabled=0 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
修改文件内容后如下：
[c7-media] name=CentOS-$releasever - Media baseurl=file:///media/cdrom/ gpgcheck=0 enabled=1 gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
再查看系统使用的源
[root@localhost yum.repos.d]# yum repolist Loaded plugins: fastestmirror c7-media | 3.6 kB 00:00:00 (1/2): c7-media/group_gz | 156 kB 00:00:00 (2/2): c7-media/primary_db | 5.7 MB 00:00:00 Loading mirror speeds from cached hostfile * epel: mirror01.idc.hinet.net repo id repo name status c7-media CentOS-7 - Media 9,591 epel/x86_64 Extra Packages for Enterprise Linux 7 - x86_64 12,449 repolist: 22,040
最后将源创建缓存以提高加载速度
[root@localhost yum.repos.d]# yum makecach Loaded plugins: fastestmirror No such command: makecach. Please use /usr/bin/yum --help [root@localhost yum.repos.d]# yum makecache Loaded plugins: fastestmirror c7-media | 3.6 kB 00:00:00 epel/x86_64/metalink | 5.6 kB 00:00:00 (1/5): c7-media/other_db | 2.5 MB 00:00:00 (2/5): c7-media/filelists_db | 6.7 MB 00:00:00 (3/5): epel/x86_64/prestodelta | 9.0 kB 00:00:00 (4/5): epel/x86_64/filelists_db | 10 MB 00:00:21 (5/5): epel/x86_64/other_db | 3.0 MB 00:01:17 Loading mirror speeds from cached hostfile * epel: mirror01.idc.hinet.net Metadata Cache Created
如果设置开机自动挂载本地源，需要在/etc/fstab添加/dev/sr0 自动挂载
# /etc/fstab
# Created by anaconda on Wed Mar 28 22:59:47 2018
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root / ext4 defaults 1 1
UUID=0cceaf55-a63f-4f0c-97c7-305c848781bc /boot ext4 defaults 1 2
/dev/mapper/centos-data /data ext4 defaults 1 2
/dev/mapper/centos-swap swap swap defaults 0 0
/dev/sr0 /media/cdrom iso9660 defaults 0 0
光盘文件类型为 iso9660
~