This system doesn't provide enough entropy to quickly generate high-quality random numbers

This system doesn't provide enough entropy to quickly generate high-quality random numbers.Installing the rng-utils/rng-tools, jitterentropy or haveged packages may help.On virtualized Linux environments, also consider using virtio-rng.The service will not start until enough entropy has been collected.

当然是安装喽，运行如下命令安装

sudo apt-get install rng-tools
sudo rngd -r /dev/urandom

在次运行刚才的命令，提示就没了。