/etc/apt/sources.list 在文件最前面添加以下条目
deb <http://mirrors.aliyun.com/ubuntu/> focal main restricted universe multiverse
deb-src <http://mirrors.aliyun.com/ubuntu/> focal main restricted universe multiverse
deb <http://mirrors.aliyun.com/ubuntu/> focal-security main restricted universe multiverse
deb-src <http://mirrors.aliyun.com/ubuntu/> focal-security main restricted universe multiverse
deb <http://mirrors.aliyun.com/ubuntu/> focal-updates main restricted universe multiverse
deb-src <http://mirrors.aliyun.com/ubuntu/> focal-updates main restricted universe multiverse
deb <http://mirrors.aliyun.com/ubuntu/> focal-proposed main restricted universe multiverse
deb-src <http://mirrors.aliyun.com/ubuntu/> focal-proposed main restricted universe multiverse
deb <http://mirrors.aliyun.com/ubuntu/> focal-backports main restricted universe multiverse
deb-src <http://mirrors.aliyun.com/ubuntu/> focal-backports main restricted universe multiverse
pip config set global.index-url <https://mirrors.aliyun.com/pypi/simple/>
ubuntu虚拟机通过proxychains把包发给本机,本机再去访问
sudo apt-get install openssh-server