3个未升级的包正在阻止Ubuntu 19.10升级到Ubuntu 20.04

Question

我在焦点释放说明上找到了升级说明，但是当我遵循它们时，它们就不起作用了。我所遵循的步骤及其产出如下：

• 您可以从Ubuntu18.04LTS或Ubuntu19.10升级到Ubuntu20.04LTS。
• 在升级之前，请确保您已经安装了Ubuntu当前版本的所有更新。

sudo apt update的输出：

$ sudo apt update  
Get:2 https //download.docker.com/linux/ubuntu eoan InRelease [43.0 kB]  
Hit:1 https //packages.cloud.google.com/apt kubernetes-xenial InRelease  
Hit:3 http //old-releases.ubuntu.com/ubuntu eoan InRelease  
Hit:4 http //old-releases.ubuntu.com/ubuntu eoan-updates InRelease  
Hit:5 http //old-releases.ubuntu.com/ubuntu eoan-backports InRelease  
Hit:6 http //old-releases.ubuntu.com/ubuntu eoan-security InRelease  
Fetched 43.0 kB in 3s (15.9 kB/s)  
Reading package lists... Done  
Building dependency tree  
Reading state information... Done  
42 packages can be upgraded. Run 'apt list --upgradable' to see them.  

• 确认您也有一个网络连接到一个官方镜像或一个本地访问镜像，因为没有脱机升级选项。

$ wget mirror.enzu.com.ubuntu  
--2021-02-15 22:33:09--  http://mirror.enzu.com.ubuntu/  
Resolving  ()... 92.242.140.21  
Connecting to  ()|92.242.140.21|:80... connected.  
HTTP request sent, awaiting response... 200 OK  
Length: unspecified [text/html]  
Saving to: ‘index.html’  
  
index.html                                          [ <=>                                                                                                   ]     894  --.-KB/s    in 0s  

2021-02-15 22:33:09 (9.06 MB/s) - ‘index.html’ saved [894]  

• 如果尚未安装update-manager-core，请安装它。

$ sudo apt install update-manager-core  
Reading package lists... Done  
Building dependency tree  
Reading state information... Done  
update-manager-core is already the newest version (1:19.04.8).  
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

• 如果您使用的是19.10，请确保/etc/update-manager/release-upgrades中的提示符行设置为“normal”，如果使用的是18.04LTS，则设置为“LTS”。

$ grep Prompt /etc/update-manager/release-upgrades  
Prompt=normal

• 使用命令sudo do-release-upgrade启动升级工具

$ sudo do-release-upgrade  
Checking for a new Ubuntu release  
Your Ubuntu release is not supported anymore.  
For upgrade information, please visit:  
http://www.ubuntu.com/releaseendoflife  

Please install all available updates for your release before upgrading.  

我做错了什么？我编辑了/etc/apt/sources.list，将其指向old-releases.ubuntu.com URL，似乎apt update成功了。为什么指令会说我可以从一个特定的版本做这件事，却告诉我我做不到，因为我是从那个版本来的？

如果能给我解释一下这个问题，我将不胜感激。

$ sudo apt full-upgrade  
[sudo] password for dalex:  
Reading package lists... Done  
Building dependency tree  
Reading state information... Done  
Calculating upgrade... Done  
The following packages have been kept back:  
  kubeadm kubectl kubelet  
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.  

Answer 1

以下三个包无法升级，并且阻止升级到20.04: kubeadm kubectl kubelet。这些包对于操作系统来说并不重要，它们可以在升级后重新安装。卸载无法升级的三个包，升级可以成功地继续。

sudo apt remove kubeadm kubectl kubelet

下面是从Ubuntu16.10升级到Ubuntu17.04时发生的错误的另一个例子。

The following packages have unmet dependencies:  
click-apparmor : Depends: python3-apparmor-click (= 0.3.17) but 0.3.18 is installed
libubuntu-app-launch4 : Depends: ubuntu-app-launch (= 0.12+17.04.20170404.2-0ubuntu2) but 0.9+16.10.20160928-0ubuntu1 is installed
ubuntu-app-launch-tools : Depends: ubuntu-app-launch (= 0.12+17.04.20170404.2-0ubuntu2) but 0.9+16.10.20160928-0ubuntu1 is installed
url-dispatcher-tools : Depends: url-dispatcher (= 0.1+17.04.20170328-0ubuntu2) but 0.1+16.10.20160816.1-0ubuntu1 is installed
E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or 
specify a solution).

正如您从错误消息中看到的那样，三个名称中包含16.10的包正在阻止安装名称中包含17.04的类似包。要解决此错误，请卸载上述错误消息中的三个包，它们的名称中包含16.10。