一、问题由来：

今天购买了一台vps测试学习下，结果使用yum命令安装python3，给我一堆错误，然后刚开始以为没有网络，使用curl访问百度什么都没有问题。然后觉得是yum源 的问题。所以百度搜索了下配置yum源。

最后问题解决，整理下这个文章，方便下次再遇到可以快速解决。

二、步骤：

1、访问清华镜像源：

清华镜像源

2、点击问号帮助：

进入官方帮助页面：

3、建议先备份 CentOS-Base.repo

sudo cp /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.bak

4、更改：/etc/yum.repos.d/CentOS-Base.repo

编辑/etc/yum.repos.d/CentOS-Base.repo

vi /etc/yum.repos.d/CentOS-Base.repo

将所有的mirrorlist这一行注销，将所有的baseurl改为清华镜像地址，保存即可

#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os&infra=$infra
baseurl=http://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/os/$basearch/

将里面的两行改为我的这种：

或者直接复制官方的（全文替换，我的正好是centos7，可以全文替换，不是7版本的系统，还是，一个一个替换吧）：

# CentOS-Base.repo
#
# The mirror system uses the connecting IP address of the client and the
# update status of each mirror to pick mirrors that are updated to and
# geographically close to the client.  You should use this for CentOS updates
# unless you are manually picking other mirrors.
#
# If the mirrorlist= does not work for you, as a fall back you can try the
# remarked out baseurl= line instead.
#
#


[base]
name=CentOS-$releasever - Base
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/os/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=os
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7

#released updates
[updates]
name=CentOS-$releasever - Updates
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/updates/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=updates
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7



#additional packages that may be useful
[extras]
name=CentOS-$releasever - Extras
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/extras/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=extras
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7



#additional packages that extend functionality of existing packages
[centosplus]
name=CentOS-$releasever - Plus
baseurl=https://mirrors.tuna.tsinghua.edu.cn/centos/$releasever/centosplus/$basearch/
#mirrorlist=http://mirrorlist.centos.org/?release=$releasever&arch=$basearch&repo=centosplus
gpgcheck=1
enabled=0
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-7

5、最后，更新软件包缓存

sudo yum makecache

6、安装python3

yum install python3

参考文章：
https://mirrors.cnnic.cn/help/centos/
https://blog.csdn.net/xiaojin21cen/article/details/84726193