CentOS 如何升级至指定版本

CentOS系统下用yum update命令默认会升级到最新版本，CentOS仓库并不维护历史版本，所以只能使用 vault.centos.org 历史版本快照进行更新。
本文以将7.0.1406升级到7.7.1908为例。

mkdir -p /etc/yum.repos.d/backup
mv /etc/yum.repos.d/*.repo /etc/yum.repos.d/backup/

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

# CentOS Vault contains rpms from older releases in the CentOS-7
# tree.
# C7.7.1908
[C7.7.1908-base]
name=CentOS-7.7.1908 - Base
baseurl=http://vault.centos.org/7.7.1908/os/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
 
[C7.7.1908-updates]
name=CentOS-7.7.1908 - Updates
baseurl=http://vault.centos.org/7.7.1908/updates/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
 
[C7.7.1908-extras]
name=CentOS-7.7.1908 - Extras
baseurl=http://vault.centos.org/7.7.1908/extras/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
 
[C7.7.1908-centosplus]
name=CentOS-7.7.1908 - CentOSPlus
baseurl=http://vault.centos.org/7.7.1908/centosplus/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1
 
[C7.7.1908-fasttrack]
name=CentOS-7.7.1908 - Fasttrack
baseurl=http://vault.centos.org/7.7.1908/fasttrack/$basearch/
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-7
enabled=1

yum repolist

yum list updates | grep "centos-release"

yum clean all
rm -rf /var/cache/yum

yum -y update

到此，更新至指定版本的任务就已完成操作了。

mv /etc/yum.repos.d/CentOS-Vault.repo /etc/yum.repos.d/backup/
mv /etc/yum.repos.d/CentOS-Vault.repo.rpmnew /etc/yum.repos.d/CentOS-Vault.repo

yum clean all
yum makecache