title: CentOS7升级CentOS8date: 2020-11-28 14:42:28
tags: Linux
categories: Linux

环境

原版本

  1. [root@wing-centos ~]# cat /etc/redhat-release && uname -r
  2. CentOS Linux release 7.6.1810 (Core)
  3. 3.10.0-1062.12.1.el7.x86_64

新版本

  1. [root@wing-centos ~]# cat /etc/redhat-release && uname -r
  2. CentOS Linux release 8.3.2011
  3. 5.10.1-1.el8.elrepo.x86_64

升级步骤

安装EPEL存储库

  1. [root@wing-centos ~]# yum install epel-release -y

安装yum-utils

  1. [root@wing-centos ~]# yum install yum-utils -y
  1. [root@wing-centos ~]# yum install rpmconf -y
  1. [root@wing-centos ~]# rpmconf -a
  2. Configuration file '/etc/cloud/cloud.cfg'
  3. -rw-r--r-- 1 root root 1234 Aug  8  2019 /etc/cloud/cloud.cfg.rpmnew
  4. -rw-r--r-- 1 root root 2646 Jul  9 23:41 /etc/cloud/cloud.cfg
  6.  ==> Package distributor has shipped an updated version.
  7.    What would you like to do about it ?  Your options are:
  8.     Y or I  : install the package maintainer's version
  9.     N or O  : keep your currently-installed version
  10.       D     : show the differences between the versions
  11.       M     : merge configuration files
  12.       Z     : background this process to examine the situation
  13.       S     : skip this file
  14.  The default action is to keep your current version.
  15. *** aliases (Y/I/N/O/D/M/Z/S) [default=N] ?
  16. Your choice: N
  17. Configuration file '/etc/cloud/cloud.cfg'
  18. -rw-r--r-- 1 root root 1416 Jul 15  2019 /etc/cloud/cloud.cfg.rpmsave
  19. -rw-r--r-- 1 root root 2646 Jul  9 23:41 /etc/cloud/cloud.cfg
  21.  ==> Package distributor has shipped an updated version.
  22.  ==> Maintainer forced upgrade. Your old version has been backed up.
  23.    What would you like to do about it?  Your options are:
  24.     Y or I  : install (keep) the package maintainer's version
  25.     N or O  : return back to your original file
  26.       D     : show the differences between the versions
  27.       M     : merge configuration files
  28.       Z     : background this process to examine the situation
  29.       S     : skip this file
  30.  The default action is to keep package maintainer's version.
  31. *** aliases (Y/I/N/O/M/D/Z/S) [default=Y] ?
  32. Your choice: Y
  1. [root@wing-centos ~]# package-cleanup --leaves
  2. [root@wing-centos ~]# package-cleanup --orphans

安装dnf

CentOS 8 默认的包管理工具已经换成了dnf，使用方法基本上和yum一样的。
{% codeblock %}
[root@wing-centos ~]# yum install dnf -y
{% endcodeblock %}

删除yum

虽然CentOS8还可以使用yum，但是有dnf已经足够了，还是删了吧。
{% codeblock %}
[root@wing-centos ~]# dnf -y remove yum yum-metadata-parser
[root@wing-centos ~]# rm -rf /etc/yum
{% endcodeblock %}

升级CentOS 7 到 CentOS 8

升级包
{% codeblock %}
[root@wing-centos ~]# dnf upgrade -y
{% endcodeblock %}

安装CentOS8发行包
{% codeblock %}
[root@wing-centos ~]# dnf install -y http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-linux-repos-8-2.el8.noarch.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-linux-release-8.3-1.2011.el8.noarch.rpm http://mirror.centos.org/centos/8/BaseOS/x86_64/os/Packages/centos-gpg-keys-8-2.el8.noarch.rpm
{% endcodeblock %}

升级EPEL储存库

  1. [root@wing-centos ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
  2. [root@wing-centos ~]# dnf upgrade -y epel-release

清除dnf缓存

  1. [root@wing-centos ~] dnf clean all

删除冲突组件，有些组件会有冲突，要先卸载。

  1. [root@wing-centos ~] rpm -e kernel sysvinit-tools gdbm kexec-tools systemd-sysv python3 --nodeps

如果有多个内核版本需要单独卸载

  1. [root@wing-centos ~]# rpm -e kernel-3.10.0-1062.12.1.el7.x86_64
  2. [root@wing-centos ~]# rpm -e kernel-3.10.0-1127.19.1.el7.x86_64

为了下载速度快一点，使用阿里云镜像

  1. [root@wing-centos yum.repos.d]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-8.repo
  2. [root@wing-centos yum.repos.d]# sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '/mirrors.aliyuncs.com/d' /etc/yum.repos.d/CentOS-Base.repo
  3. [root@wing-centos yum.repos.d]# dnf install -y https://mirrors.aliyun.com/epel/epel-release-latest-8.noarch.rpm
  4. [root@wing-centos yum.repos.d]# sed -i 's|^#baseurl=https://download.fedoraproject.org/pub|baseurl=https://mirrors.aliyun.com|' /etc/yum.repos.d/epel*
  5. [root@wing-centos yum.repos.d]# sed -i 's|^metalink|#metalink|' /etc/yum.repos.d/epel*

开始升级
{% codeblock %}
[root@wing-centos ~]# dnf —allowerasing distro-sync -y
{% endcodeblock %}

升级到最新内核

  1. [root@wing-centos ~] dnf install -y https://www.elrepo.org/elrepo-release-8.el8.elrepo.noarch.rpm
  2. [root@wing-centos ~] dnf --enablerepo=elrepo-kernel -y install kernel-ml

查看系统版本

重启主机后查看系统版本是否已经更新了
{% codeblock %}
[root@wing-centos ~]# cat /etc/redhat-release && uname -r
{% endcodeblock %}

参考：
https://www.tecmint.com/upgrade-centos-7-to-centos-8/
https://developer.aliyun.com/mirror/centos?spm=a2c6h.13651102.0.0.3e221b11dZPNeJ
https://blog.csdn.net/u010039418/article/details/108588941
https://blog.yowko.com/centos7-upgrade-centos8-linux-kernel5/