访问 Ubuntu 镜像库地址： https://hub.docker.com/_/ubuntu?tab=tags&page=1。

可以通过 Sort by 查看其他版本的 Ubuntu。默认是最新版本 ubuntu:latest 。

1、拉取镜像，这边选择20.04

[root@VM-8-2-centos ~]# docker pull ubuntu:focal-20220801
focal-20220801: Pulling from library/ubuntu
3b65ec22a9e9: Pull complete
Digest: sha256:af5efa9c28de78b754777af9b4d850112cad01899a5d37d2617bb94dc63a49aa
Status: Downloaded newer image for ubuntu:focal-20220801
docker.io/library/ubuntu:focal-20220801
[root@VM-8-2-centos ~]# docker images
REPOSITORY                                                  TAG              IMAGE ID       CREATED         SIZE
ubuntu                                                      focal-20220801   3bc6e9f30f51   3 weeks ago     72.8MB

启动并进容器，确认系统版本

[root@VM-8-2-centos Nps-Server]# docker run -itd --name ubuntu20.4 ubuntu:focal-20220801
[root@VM-8-2-centos Nps-Server]# docker exec -it ubuntu20.4 bash
root@8fe2f23b184e:/# cat /etc/issue
Ubuntu 20.04.4 LTS \n \l

ubuntu 20.04更换阿里源

echo "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">/etc/apt/sources.list

更新软件列表和更新软件

apt-get update
apt-get upgrade

安装必备软件：

apt-get install net-tools inetutils-ping openssh-server samba samba-common git vim curl