Ubuntu 20.04 Focal 升级 Ubuntu 22.04 Jammy
本文将指导如何升级 Ubuntu 20.04 Focal 到 Ubuntu 22.04 Jammy。
前言 Ubuntu 22.04 Jammy Jellyfish 已正式发布，如果您使用 Ubuntu 20.04，那么可以参考本站教程升级。
准备工作 除非你是物理服务器，以及没有用过奇奇怪怪定制或修改的内核的 KVM 构架的 VPS 和云主机，否则升级大版本更新内核是有一定机率导致 Grub 加载失败的，切记备份重要数据！
OpenVZ 6 和 LXC 构架的 VPS 是无法升级的，因为他们没有自己独立的内核
再强调一遍，一定要备份重要数据！
以下操作需要在 root 用户下完成，请使用 sudo -i 或 su root 切换到 root 用户进行操作
更新系统 首先需要更新你当前的系统
apt update apt upgrade -y apt dist-upgrade -y apt autoclean apt autoremove -y 如果内核更新了，建议重启让最新的内核生效。
升级系统 我们有两种方法升级到最新的系统，第一种是和 Debian 类似，手工修改 apt 源文件：
首先更新 apt 源，替换 focal 为 jammy：
sed -i ‘s/focal/jammy/g’ /etc/apt/sources.list sed -i ‘s/focal/jammy/g’ /etc/apt/sources.list.d/*.list 默认的系统 apt 源文件 /etc/apt/sources.list 应该是类似这样的：
See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ jammy main restricted
deb-src http://archive.ubuntu.com/ubuntu/ jammy main restricted
Major bug fix updates produced after the final release of the
distribution.
deb http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted
deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted
N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
team. Also, please note that software in universe WILL NOT receive any
review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ jammy universe
deb-src http://archive.ubuntu.com/ubuntu/ jammy universe
deb http://archive.ubuntu.com/ubuntu/ jammy-updates universe
deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates universe
N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
team, and may not be under a free licence. Please satisfy yourself as to
your rights to use the software. Also, please note that software in
multiverse WILL NOT receive any review or updates from the Ubuntu
security team.
deb http://archive.ubuntu.com/ubuntu/ jammy multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jammy multiverse
deb http://archive.ubuntu.com/ubuntu/ jammy-updates multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates multiverse
N.B. software from this repository may not have been tested as
extensively as that contained in the main release, although it includes
newer versions of some applications which may provide useful features.
Also, please note that software in backports WILL NOT receive any review
or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse
Uncomment the following two lines to add software from Canonical’s
‘partner’ repository.
This software is not part of Ubuntu, but is offered by Canonical and the
respective vendors as a service to Ubuntu users.
deb http://archive.canonical.com/ubuntu jammy partner
deb-src http://archive.canonical.com/ubuntu jammy partner
deb http://archive.ubuntu.com/ubuntu jammy-security main restricted
deb-src http://archive.ubuntu.com/ubuntu jammy-security main restricted
deb http://archive.ubuntu.com/ubuntu jammy-security universe
deb-src http://archive.ubuntu.com/ubuntu jammy-security universe
deb http://archive.ubuntu.com/ubuntu jammy-security multiverse
deb-src http://archive.ubuntu.com/ubuntu jammy-security multiverse
国内服务器可以替换 archive.ubuntu.com 为 mirrors.tuna.tsinghua.edu.cn
然后我们再次执行更新系统：
apt update apt upgrade -y apt dist-upgrade -y 更新过程种会提示一些软件是否需要自动重启，选 Yes 即可，以及一些软件的配置文件是否需要更新，按照自己的情况选择即可，默认回车即视为使用旧的配置文件，一般会出现在 OpenSSH 等软件的更新上。
更新后删除不必要的软件和依赖：
apt autoclean apt autoremove -y 然后我们使用 reboot 命令重启系统，耐心等待后，查看最新的系统版本：
root@ubuntu ~ # lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description: Ubuntu 22.04 LTS Release: 22.04 Codename: jammy root@ubuntu ~ # uname -a Linux ubuntu 5.15.0-25 #4-Ubuntu SMP Fri Apr 1 07:36:38 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux 这时我们就已经更新到了最新的 Ubuntu 22.04 Jammy 和内核了。
第二种方法是使用 do-release-upgrade 命令
首先安装 update-manager-core 软件包：
apt install update-manager-core 然后运行 do-release-upgrade -d 即可更新，其他方法和上面一样，不再详细解释。
如果添加过一些 PPA 源，如果他们还未发布最新版本的软件，可以临时先取消，比如
add-apt-repository –remove ppa:ondrej/php
原文链接：https://u.sb/ubuntu-upgrade/