我们有一台旧的 Ubuntu 14 服务器，我们在该服务器上安装了 certbot 并加密 SSL 证书。然后我们将服务器升级到 ubuntu 20。
从那时起，每当我尝试使用sudo certbot --apache或更新命令更新或生成新证书时，都会收到此错误：
Bootstrapping dependencies for Debian-based OSes... (you can skip this with --no-bootstrap)
Hit:1 http://us-west-2.ec2.archive.ubuntu.com/ubuntu focal InRelease
Hit:2 http://us-west-2.ec2.archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:3 http://us-west-2.ec2.archive.ubuntu.com/ubuntu focal-backports InRelease
Hit:4 https://download.docker.com/linux/ubuntu focal InRelease
Hit:5 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu focal InRelease
Hit:6 http://ppa.launchpad.net/ondrej/php/ubuntu focal InRelease
Get:7 http://security.ubuntu.com/ubuntu focal-security InRelease [114 kB]
Fetched 114 kB in 2s (72.8 kB/s)
Reading package lists... Done
Reading package lists... Done
Building dependency tree
Reading state information... Done
Note, selecting 'python-is-python2' instead of 'python'
Note, selecting 'python-dev-is-python2' instead of 'python-dev'
Package python-virtualenv is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
E: Package 'python-virtualenv' has no installation candidate
我尝试过无数的论坛和技巧，包括这个谷歌热门话题 ->https://stackoverflow.com/questions/62314556/how-to-install-virtualenv-on-ubuntu-20-04-gcp-instance，但还没有运气 :( 有什么想法吗？