如何将CentOS7升级至CentOS8(详细步骤)

这篇文章以具体的示例来介绍一下从CentOS 7升级值CentOS 8的方法。

事前准备

最小化安装CentOS 7,具体版本如下所示:7.6.1810

  [root@liumiao ~]# uname -a  Linux devops 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux  [root@liumiao ~]# cat /etc/redhat-release   CentOS Linux release 7.6.1810 (Core)   [root@liumiao ~]#   

步骤1: 安装epel-relase、yum-utils和rpmconf

执行命令:yum install yum-utils epel-release -y

执行日志如下所示:

  ...省略  ========================================================================================================================================   Package        Arch      Version        Repository     Size  ========================================================================================================================================  Installing:   epel-release      noarch      7-11         extras      15 k   yum-utils       noarch      1.1.31-52.el7      base      121 k  Installing for dependencies:   libxml2-python      x86_64      2.9.1-6.el7_2.3      base      247 k   python-chardet      noarch      2.2.1-3.el7       base      227 k   python-kitchen      noarch      1.1.1-5.el7       base      267 k    Transaction Summary  ========================================================================================================================================  Install 2 Packages (+3 Dependent packages)  ...省略

安装命令:yum install rpmconf -y

安装日志如下所示:

  [root@liumiao ~]# yum install rpmconf -y  ...省略  ========================================================================================================================================   Package       Arch       Version        Repository     Size  ========================================================================================================================================  Installing:   rpmconf       noarch       0.3.4-1.el7       epel       21 k    Transaction Summary  ========================================================================================================================================  Install 1 Package  ...省略  Complete!
[root@liumiao ~]# 

步骤2: 安装前检查

检查配置:rpmconf -a

执行日志如下所示,如有选择直接使用缺省设定。

  [root@liumiao ~]# rpmconf -a  [root@liumiao ~]#   

检查叶节点:列出和其他RPM没有依赖的软件包

  [root@liumiao ~]# package-cleanup --leaves  Loaded plugins: fastestmirror  libsysfs-2.1.0-16.el7.x86_64  [root@liumiao ~]# 

检查不再提供的软件包:列出当前仓库中不提供升级的软件包信息

  [root@liumiao ~]# package-cleanup --orphans  Loaded plugins: fastestmirror  Loading mirror speeds from cached hostfile   * base: mirror.bit.edu.cn   * epel: hkg.mirror.rackspace.com   * extras: mirror.bit.edu.cn   * updates: ap.stykers.moe  GeoIP-1.5.0-13.el7.x86_64  ...省略  yum-plugin-fastestmirror-1.1.31-50.el7.noarch  [root@liumiao ~]#    

步骤3: 安装dnf 并执行dnf update

CentOS 8使用dnf作为缺省的包管理工具,使用yum安装自己的替代工具dnf并删除自己。

安装命令:yum install dnf -y

执行日志如下所示:

  [root@liumiao ~]# yum install dnf -y  ...省略  ========================================================================================================================================   Package                Arch           Version                 Repository        Size  ========================================================================================================================================  Installing:   dnf                  noarch          4.0.9.2-1.el7_6             extras          357 k  Installing for dependencies:   deltarpm                x86_64          3.6-3.el7                base           82 k   dnf-data                noarch          4.0.9.2-1.el7_6             extras          51 k   libcomps                x86_64          0.1.8-12.el7              extras          75 k   libdnf                 x86_64          0.22.5-1.el7_6             extras          533 k   libmodulemd              x86_64          1.6.3-1.el7               extras          141 k   librepo                x86_64          1.8.1-7.el7               base           81 k   libreport-filesystem          x86_64          2.1.11-43.el7.centos          base           40 k   libsolv                x86_64          0.6.34-4.el7              base           329 k   libyaml                x86_64          0.1.4-11.el7_0             base           55 k   python-enum34             noarch          1.0.4-1.el7               base           52 k   python2-dnf              noarch          4.0.9.2-1.el7_6             extras          414 k   python2-hawkey             x86_64          0.22.5-1.el7_6             extras          68 k   python2-libcomps            x86_64          0.1.8-12.el7              extras          47 k   python2-libdnf             x86_64          0.22.5-1.el7_6             extras          608 k    Transaction Summary  ========================================================================================================================================  Install 1 Package (+14 Dependent packages)  ...省略  [root@liumiao ~]#    

清除yum:dnf -y remove yum yum-metadata-parser && rm -rf /etc/yum

执行日志如下所示:

  [root@liumiao ~]# dnf -y remove yum yum-metadata-parser  Dependencies resolved.  ========================================================================================================================================   Package                  Arch          Version                Repository        Size  ========================================================================================================================================  Removing:   yum                    noarch         3.4.3-161.el7.centos         @System         5.6 M   yum-metadata-parser            x86_64         1.1.4-10.el7             @System          57 k  Removing dependent packages:   yum-plugin-fastestmirror         noarch         1.1.31-50.el7             @System          53 k   yum-utils                 noarch         1.1.31-52.el7             @System         337 k    Transaction Summary  ========================================================================================================================================  Remove 4 Packages    Freed space: 6.0 M  Running transaction check  Transaction check succeeded.  Running transaction test  Transaction test succeeded.  Running transaction   Preparing    :                                                        1/1    Erasing     : yum-utils-1.1.31-52.el7.noarch                                         1/4    Erasing     : yum-plugin-fastestmirror-1.1.31-50.el7.noarch                                 2/4    Erasing     : yum-3.4.3-161.el7.centos.noarch                                        3/4    Erasing     : yum-metadata-parser-1.1.4-10.el7.x86_64                                    4/4    Verifying    : yum-3.4.3-161.el7.centos.noarch                                        1/4    Verifying    : yum-metadata-parser-1.1.4-10.el7.x86_64                                    2/4    Verifying    : yum-plugin-fastestmirror-1.1.31-50.el7.noarch                                 3/4    Verifying    : yum-utils-1.1.31-52.el7.noarch                                         4/4    Removed:   yum-3.4.3-161.el7.centos.noarch   yum-metadata-parser-1.1.4-10.el7.x86_64   yum-plugin-fastestmirror-1.1.31-50.el7.noarch      yum-utils-1.1.31-52.el7.noarch       Complete!  [root@liumiao ~]# ls /etc/yum  pluginconf.d protected.d vars  [root@liumiao ~]# rm -rf /etc/yum  [root@liumiao ~]#

就像使用yum update那样使用dnf update进行更新。

  [root@liumiao ~]# dnf upgrade  Extra Packages for Enterprise Linux 7 - x86_64                             5.6 MB/s | 16 MB   00:02    CentOS-7 - Base                                             3.5 MB/s | 10 MB   00:02    CentOS-7 - Updates                                           2.9 MB/s | 5.4 MB   00:01    CentOS-7 - Extras                                            40 kB/s | 251 kB   00:06     ...省略  ========================================================================================================================================   Package                  Arch        Version                   Repository      Size  ========================================================================================================================================  Upgrading:   epel-release                noarch       7-12                     epel         15 k   ...省略   tzdata                   noarch       2019c-1.el7                 updates       493 k  Installing dependencies:   bind-export-libs              x86_64       32:9.11.4-9.P2.el7              base         1.1 M   geoipupdate                x86_64       2.5.0-1.el7                 base         35 k   kernel                   x86_64       3.10.0-1062.4.3.el7             updates        50 M    Transaction Summary  ========================================================================================================================================  Install  3 Packages  Upgrade 164 Packages    Total download size: 259 M  Is this ok [y/N]: y  Downloading Packages:   ...省略   Installed:   bind-export-libs-32:9.11.4-9.P2.el7.x86_64     geoipupdate-2.5.0-1.el7.x86_64     kernel-3.10.0-1062.4.3.el7.x86_64        Complete!  [root@liumiao ~]#

使用dnf更新CentOS 8的包

执行日志如下所示:

  [root@liumiao ~]# dnf -y upgrade http://mirror.bytemark.co.uk/centos/8/BaseOS/x86_64/os/Packages/centos-release-8.0-0.1905.0.9.el8.x86_64.rpm    Extra Packages for Enterprise Linux 7 - x86_64                             4.3 MB/s | 16 MB   00:03    Last metadata expiration check: 0:00:01 ago on Wed 20 Nov 2019 07:58:07 AM EST.  centos-release-8.0-0.1905.0.9.el8.x86_64.rpm                               13 kB/s | 26 kB   00:01    Dependencies resolved.  ========================================================================================================================================   Package             Arch           Version                 Repository           Size  ========================================================================================================================================  Upgrading:   centos-release          x86_64          8.0-0.1905.0.9.el8           @commandline          26 k    Transaction Summary  ========================================================================================================================================  Upgrade 1 Package    Total size: 26 k  Downloading Packages:  Running transaction check  Transaction check succeeded.  Running transaction test  Transaction test succeeded.  Running transaction   Preparing    :                                                        1/1    Upgrading    : centos-release-8.0-0.1905.0.9.el8.x86_64                                    1/2    Cleanup     : centos-release-7-7.1908.0.el7.centos.x86_64                                  2/2    Verifying    : centos-release-8.0-0.1905.0.9.el8.x86_64                                    1/2    Verifying    : centos-release-7-7.1908.0.el7.centos.x86_64                                  2/2    Upgraded:   centos-release-8.0-0.1905.0.9.el8.x86_64                                                   Complete!  [root@liumiao ~]#

更新epel仓库

执行日志如下所示:

  [root@liumiao ~]# dnf -y upgrade https://dl.fedoraproject.org/pub/epel/epel-release-latest-8.noarch.rpm  Extra Packages for Enterprise Linux 7 - x86_64                             578 kB/s | 16 MB   00:28    CentOS-8 - Base                                             635 kB/s | 7.9 MB   00:12    CentOS-8 - Extras                                            1.7 kB/s | 2.1 kB   00:01    CentOS-8 - AppStream                                          1.3 MB/s | 6.3 MB   00:04    epel-release-latest-8.noarch.rpm                                    7.7 kB/s | 21 kB   00:02    Dependencies resolved.  ========================================================================================================================================   Package              Arch             Version            Repository             Size  ========================================================================================================================================  Upgrading:   epel-release            noarch            8-7.el8            @commandline            21 k    Transaction Summary  ========================================================================================================================================  Upgrade 1 Package    Total size: 21 k  Downloading Packages:  Running transaction check  Transaction check succeeded.  Running transaction test  Transaction test succeeded.  Running transaction   Preparing    :                                                        1/1    Upgrading    : epel-release-8-7.el8.noarch                                          1/2    Cleanup     : epel-release-7-12.noarch                                            2/2    Verifying    : epel-release-8-7.el8.noarch                                          1/2    Verifying    : epel-release-7-12.noarch                                            2/2    Upgraded:   epel-release-8-7.el8.noarch                                                         Complete!  [root@liumiao ~]# 

 此时确认版本信息,已经发生了变化

  [root@liumiao ~]# cat /etc/redhat-release   CentOS Linux release 8.0.1905 (Core)   [root@liumiao ~]#   

步骤4: 删除无用文件和CentOS 7的内核并安装CentOS 8的内核

删除无用的临时文件:dnf clean all

执行日志如下所示:

  [root@liumiao ~]# dnf clean all  62 files removed  [root@liumiao ~]#

删除CentOS 7的旧核: rpm -e `rpm -q kernel`

执行日志如下所示:

  [root@liumiao ~]# rpm -e `rpm -q kernel`  [root@liumiao ~]#  

确认删除冲突的包

  [root@liumiao ~]# rpm -e --nodeps sysvinit-tools  [root@liumiao ~]# 

更新CentOS 8系统

  [root@liumiao ~]# dnf -y --releasever=8 --allowerasing --setopt=deltarpm=false distro-sync  Extra Packages for Enterprise Linux 8 - x86_64                             2.0 MB/s | 3.5 MB   00:01    CentOS-8 - Base                                             160 kB/s | 7.9 MB   00:50    CentOS-8 - AppStream                                          1.6 MB/s | 6.3 MB   00:03    CentOS-8 - Extras                                            950 B/s | 2.1 kB   00:02    Last metadata expiration check: 0:00:02 ago on Wed 20 Nov 2019 08:09:51 AM EST.  Dependencies resolved.  ========================================================================================================================================   Package                Arch      Version                        Repository     Size  ========================================================================================================================================  Upgrading:   rpmconf                noarch     1.0.20-1.el8                      epel        26 k  ...省略  Removed:   deltarpm-3.6-3.el7.x86_64           libselinux-python-2.5-14.1.el7.x86_64    libxml2-python-2.9.1-6.el7_2.3.x86_64      newt-python-0.52.15-4.el7.x86_64       python-2.7.5-86.el7.x86_64         python-chardet-2.2.1-3.el7.noarch        python-firewall-0.6.3-2.el7_7.2.noarch    python-kitchen-1.1.1-5.el7.noarch      python-libs-2.7.5-86.el7.x86_64         python-linux-procfs-0.4.11-4.el7.noarch    python-schedutils-0.4-6.el7.x86_64     python-slip-0.4.0-4.el7.noarch          python-slip-dbus-0.4.0-4.el7.noarch      python-urlgrabber-3.10-9.el7.noarch     python2-dnf-4.0.9.2-1.el7_6.noarch        python2-hawkey-0.22.5-1.el7_6.x86_64     python2-libcomps-0.1.8-12.el7.x86_64    python2-libdnf-0.22.5-1.el7_6.x86_64       pyxattr-0.5.1-5.el7.x86_64          rpm-python-4.11.3-40.el7.x86_64       systemd-sysv-219-67.el7_7.2.x86_64        Complete!  [root@liumiao ~]# 

此时通过uname -a确认内核状态,仍是3.10.

  [root@liumiao ~]# uname -a  Linux devops 3.10.0-957.el7.x86_64 #1 SMP Thu Nov 8 23:39:32 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux  [root@liumiao ~]# cat /etc/redhat-release   CentOS Linux release 8.0.1905 (Core)   [root@liumiao ~]#

由于前文已经更新,此时如执行dnf -y install kernel-core会提示already updated,接下来更新一下CentOS 8的最小化安装的相关package,执行如下命令即可:

  [root@liumiao ~]# dnf -y groupupdate "Core" "Minimal Install"  Last metadata expiration check: 0:13:34 ago on Wed 20 Nov 2019 08:09:51 AM EST.  Dependencies resolved.  ========================================================================================================================================   Package                 Arch       Version                      Repository      Size  ========================================================================================================================================  Installing group/module packages:   dnf-plugin-spacewalk          noarch      2.8.5-11.module_el8.0.0+180+337688dc       AppStream       24 k   dnf-plugins-core            noarch      4.0.2.2-3.el8                   BaseOS        59 k  ...省略  [root@liumiao ~]#

步骤5: 重启系统

重启之后即可确认内核和版本文件信息均已升至最新

  [root@liumiao ~]# uname -a  Linux devops 4.18.0-80.11.2.el8_0.x86_64 #1 SMP Tue Sep 24 11:32:19 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux  [root@liumiao ~]# cat /etc/redhat-release   CentOS Linux release 8.0.1905 (Core)   [root@liumiao ~]# 

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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