Azure虚拟机中Ubuntu 18.04升级至20.04失败，依赖问题无法解决

看起来你在Azure虚拟机上升级Ubuntu 18.04到20.04时碰到了相当棘手的依赖阻塞问题，我先帮你梳理下目前的操作轨迹和遇到的核心问题：

背景与初始尝试 #

因为Ubuntu 18.04已停止支持，你需要升级到20.04，但最直接的升级命令sudo do-release-upgrade意外失败（没有终端响应输出），于是转而尝试手动更新包管理流程。

已执行操作及对应结果 #

1. 执行sudo apt update
   更新过程正常完成，最终提示有2个可升级包：

   Hit:1 http://azure.archive.ubuntu.com/ubuntu focal InRelease
   Get:2 http://azure.archive.ubuntu.com/ubuntu focal-updates InRelease [114 kB]
   Get:3 http://azure.archive.ubuntu.com/ubuntu focal-backports InRelease [108 kB]
   Hit:4 http://security.ubuntu.com/ubuntu focal-security InRelease
   Get:5 http://azure.archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages [2917 kB]
   Get:6 http://azure.archive.ubuntu.com/ubuntu focal-updates/restricted amd64 Packages [2419 kB]
   Fetched 5558 kB in 2s (2538 kB/s)
   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   2 packages can be upgraded. Run 'apt list --upgradable' to see them.
   

2. 执行sudo apt upgrade
   触发依赖未满足错误，提示几个linux-tools包缺少对应的linux-azure-tools依赖：

   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   You might want to run 'apt --fix-broken install' to correct these.
   The following packages have unmet dependencies:
   linux-tools-5.4.0-1059-azure : Depends: linux-azure-tools-5.4.0-1059 but it is not installed
   linux-tools-5.4.0-1100-azure : Depends: linux-azure-tools-5.4.0-1100 but it is not installed
   linux-tools-5.4.0-1109-azure : Depends: linux-azure-tools-5.4.0-1109 but it is not installed
   E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
   

3. 执行sudo apt --fix-broken install
   系统尝试自动修复依赖，准备安装缺失的linux-azure-tools包，但最终执行失败：

   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   Correcting dependencies... Done
   # 此处省略自动安装可清理包列表
   The following additional packages will be installed:
   linux-azure-tools-5.4.0-1059 linux-azure-tools-5.4.0-1100 linux-azure-tools-5.4.0-1109
   The following NEW packages will be installed:
   linux-azure-tools-5.4.0-1059 linux-azure-tools-5.4.0-1100 linux-azure-tools-5.4.0-1109
   0 upgraded, 3 newly installed, 0 to remove and 2 not upgraded.
   3 not fully installed or removed.
   Need to get 0 B/15.8 MB of archives.
   After this operation, 74.0 MB of additional disk space will be used.
   Do you want to continue? [Y/n]
   
   E: Sub-process /usr/bin/dpkg exited unexpectedly
   

4. 执行sudo dpkg --configure -a
   依然无法解决依赖问题，三个linux-tools包因缺失依赖无法完成配置：

   dpkg: dependency problems prevent configuration of linux-tools-5.4.0-1059-azure:
   linux-tools-5.4.0-1059-azure depends on linux-azure-tools-5.4.0-1059; however:
   Package linux-azure-tools-5.4.0-1059 is not installed.
   
   dpkg: error processing package linux-tools-5.4.0-1059-azure (--configure):
   dependency problems - leaving unconfigured
   # 此处省略另外两个包的类似错误信息
   Errors were encountered while processing:
   linux-tools-5.4.0-1059-azure
   linux-tools-5.4.0-1109-azure
   linux-tools-5.4.0-1100-azure
   

5. 尝试sudo apt autoremove
   同样被未满足的依赖阻塞，无法执行：

   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   You might want to run 'apt --fix-broken install' to correct these.
   The following packages have unmet dependencies:
   linux-tools-5.4.0-1059-azure : Depends: linux-azure-tools-5.4.0-1059 but it is not installed
   linux-tools-5.4.0-1100-azure : Depends: linux-azure-tools-5.4.0-1100 but it is not installed
   linux-tools-5.4.0-1109-azure : Depends: linux-azure-tools-5.4.0-1109 but it is not installed
   E: Unmet dependencies. Try 'apt --fix-broken install' with no packages (or specify a solution).
   

可能的解决方向 #

1. 强制移除有问题的包后再修复
   先尝试强制移除那些因依赖缺失无法配置的linux-tools包，再重新修复依赖：

   sudo dpkg --remove --force-remove-reinstreq linux-tools-5.4.0-1059-azure linux-tools-5.4.0-1100-azure linux-tools-5.4.0-1109-azure
   sudo apt --fix-broken install
   

   完成后再重新运行sudo apt update && sudo apt upgrade，之后尝试sudo do-release-upgrade。

2. 手动下载缺失的依赖包安装
   针对三个缺失的linux-azure-tools包，从Ubuntu官方包仓库找到对应amd64架构的.deb文件（版本号分别为5.4.0-1059、5.4.0-1100、5.4.0-1109），用dpkg手动安装：

   sudo dpkg -i linux-azure-tools-5.4.0-1059_*.deb linux-azure-tools-5.4.0-1100_*.deb linux-azure-tools-5.4.0-1109_*.deb
   sudo apt --fix-broken install
   

3. 重置包管理状态
   如果上面的方法都无效，可以尝试清理dpkg的缓存并重新初始化：

   sudo rm /var/lib/dpkg/lock-frontend
   sudo rm /var/cache/apt/archives/lock
   sudo dpkg --configure -a
   sudo apt clean && sudo apt update
   

备注：内容来源于stack exchange，提问作者Piotr Śródka