Centos6.6升级到Centos7.2： 新版的7.4不支持直接升级

step 1：

[root@localhost ~]# cat /etc/yum.repos.d/upgrade.repo

[upgrade]

name=upgrade

baseurl=http://dev.centos.org/centos/6/upg/x86_64/

enable=1

gpgcheck=0

step 2：

yum erase openscap

yum install http://dev.centos.org/centos/6/upg/x86_64/Packages/openscap-1.0.8-1.0.1.el6.centos.x86_64.rpm

yum install openscap-1.0.8

[root@localhost ~]# yum install preupgrade-assistant-contents redhat-upgrade-tool preupgrade-assistant

step 3:

[root@localhost ~]# preupg

step 4：

http://vault.centos.org/centos/7.2.1511/os/x86\_64/

[root@localhost ~]# rpm --import http://mirrors.163.com/centos/7.0.1406/os/x86_64/RPM-GPG-KEY-CentOS-7

[root@localhost ~]# redhat-upgrade-tool --network 7 --instrepo http://mirrors.163.com/centos/7.0.1406/os/x86_64/

(265/266): zlib-1.2.7-13.el7.x86_64.rpm | 89 kB 00:00

(266/266): zlib-devel-1.2.7-13.el7.x86_64.rpm | 49 kB 00:00

testing upgrade transaction rpm transaction 100%

[===========================================] rpm install 100%

[===========================================] setting up system for upgrade Finished. Reboot to start upgrade.

升级centos7过程其实非常的简单了，这个也是linux内核系统的一个优点了，升级系统可以直接使用简单的命令完以