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前言

Centos7.6升级系统版本到Centos7.9
参考：https://www.cnblogs.com/wutao-007/p/16921927.html

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一、查看当前版本

cat /etc/redhat-release 

结果输出

CentOS Linux release 7.6.1810 (Core) 

二、更换yum源并升级

1.更换yum源

备份已有源文件后更换为阿里云的源文件

yum install wget -y
mkdir -p /etc/yum.repos.d/CentOS-Base.repo.backup
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
wget -O /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo
yum makecache
wget -O /etc/yum.repos.d/epel-7.repo http://mirrors.aliyun.com/repo/epel-7.repo
yum -y install epel-release

2.执行升级并重启

yum update -y;reboot;

输出

已安装:iwl7260-firmware.noarch 0:25.30.13.0-82.el7_9                  kernel.x86_64 0:3.10.0-1160.108.1.el7                 作为依赖被安装:bc.x86_64 0:1.06.95-13.el7    bind-export-libs.x86_64 32:9.11.4-26.P2.el7_9.15    geoipupdate.x86_64 0:2.5.0-2.el7 

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三、查看升级结果

cat /etc/redhat-release 

结果输出

CentOS Linux release 7.9.2009 (Core)

总结

记录一下centos7.6升级到7.9的方法。