Fedora系统升级

根据官方指南，每次建议只升级1个版本，至多每次只能升级2个版本。

查看当前系统版本

$ uname -a
Linux localhost.localdomain 4.1.13-100.fc21.x86_64 #1 SMP Tue Nov 10 13:13:20 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

Fedora 21升级Fedora 27

Fedora 21先升级Fedora 22

耗时很长，建议在较好的网络环境下进行

$ sudo dnf upgrade --refresh
$ sudo dnf install dnf-plugin-system-upgrade
$ sudo dnf system-upgrade download --refresh --releasever=22 --allowerasing --setopt=keepcache=1

经常遇到的问题之一：提示GPG-KEY缺失

Install     257 Packages
Upgrade    1646 Packages
Remove        7 Packages
Downgrade     4 Packages
Total download size: 1.4 G

warning: /var/lib/dnf/system-upgrade/geos-3.4.2-3.fc22.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8e1431d5: NOKEY
Curl error (37): Couldn't read a file:// file for file:///etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64 [Couldn't open file /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64]

下载RPM-GPG-KEY，下载links

$ sudo rpm --import '/home/brian/Downloads/RPM-GPG-KEY-rpmfusion-free-fedora-22'
$ sudo rpmkeys --import /etc/pki/rpm-gpg/RPM-GPG-KEY-rpmfusion-free-fedora-22

更名：

$ sudo cp RPM-GPG-KEY-fedora-22-x86_64 RPM-GPG-KEY-fedora-x86_64

重新安装

$ sudo dnf system-upgrade download --refresh --releasever=22 --allowerasing --setopt=keepcache=1

根据提示导入key

warning: /var/lib/dnf/system-upgrade/geos-3.4.2-3.fc22.x86_64.rpm: Header V3 RSA/SHA256 Signature, key ID 8e1431d5: NOKEY
Importing GPG key 0x8E1431D5:
 Userid     : "Fedora (22) <fedora@fedoraproject.org>"
 Fingerprint: C527 EA07 A934 9B58 9C35 E1BF 11AD C094 8E14 31D5
 From       : /etc/pki/rpm-gpg/RPM-GPG-KEY-fedora-x86_64
Is this ok [y/N]: y
Key imported successfully
...

启动安装事务，需要很长的时间，请耐心等待。
更新+重启动

$ sudo dnf system-upgrade reboot

Fedora 22再升级Fedora 23

Fedora 22升级Fedora 23，四步即可，等待时间比较长

sudo dnf update --refresh
sudo dnf install dnf-plugin-system-upgrade
sudo dnf system-upgrade download --releasever=23
sudo dnf system-upgrade reboot

Fedora 23再升级Fedora 25

更新key，升级，重新启动：

$ sudo cp RPM-GPG-KEY-fedora-25-x86_64 RPM-GPG-KEY-fedora-x86_64

$ sudo dnf system-upgrade download --refresh --releasever=25 --allowerasing --setopt=keepcache=1

$ sudo dnf system-upgrade reboot

解决错误事务检查错误

Error: Transaction check error:
  file /usr/share/man/man1/vim.1.gz from install of vim-minimal-2:8.0.617-1.fc24.x86_64 conflicts with file from package vim-common-2:7.4.1868-1.fc22.x86_64
  file /usr/lib64/gstreamer-1.0/libgstopus.so from install of gstreamer1-plugins-base-1.8.3-2.fc24.x86_64 conflicts with file from package gstreamer1-plugins-bad-free-1.6.4-1.fc23.x86_64

删除vim和gstreamer

$ sudo dnf remove vim
# dnf remove gstreamer

解决conflicts with file from错误

# yum -y remove gstreamer1-plugins-bad-free-1.6.4-1.fc23.x86_64

继续下载更新所需库：

$ sudo dnf system-upgrade download --refresh --releasever=25 --allowerasing --setopt=keepcache=1

启动更新:

# dnf system-upgrade reboot

查看当前系统版本：

$ uname -a
Linux localhost.localdomain 4.13.16-100.fc25.x86_64 #1 SMP Mon Nov 27 19:52:46 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

Fedora 25再升级Fedora 27

经测试，支持跨版本更新哦。

$ uname -a
Linux localhost.localdomain 4.15.15-300.fc27.x86_64 #1 SMP Mon Apr 2 23:14:02 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux