我有一台安装了 Docker 的 Ubuntu 机器。（Ubuntu 版本是 20.04，但这也会影响 18.04，也可能影响非 LTS 版本。）软件包docker.io从focal-security失败：
Preparing to unpack .../docker.io_20.10.7-0ubuntu1~20.04.1_amd64.deb ...\nThe aufs storage-driver is no longer supported.\nPlease ensure that none of your containers are\nusing the aufs storage driver, remove the directory\n/var/lib/docker/aufs and try again.\ndpkg: error processing archive /var/cache/apt/archives/docker.io_20.10.7-0ubuntu1~20.04.1_amd64.deb (--unpack):\n new docker.io package pre-installation script subprocess returned error exit status 1\ndpkg: error while cleaning up:\n installed docker.io package post-installation script subprocess returned error exit status 1\n这是一个已知的错误，但根据Ubuntu Docker …