Docker 要求 Ubuntu 系统的内核版本高于 3.10 ，查看本页面的前提条件来验证你的 Ubuntu 版本是否支持 Docker。
通过 uname -r 命令查看你当前的内核版本
uname -r 4.15.0-20-generic
版本是4.15所以就没问题
然后使用脚本安装Docker
1.获取最新版本的Docker安装包
wget -qO- https://get.docker.com/ | sh
安装完会有个提示：
If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like: sudo usermod -aG docker limingxing(我的用户名) Remember that you will have to log out and back in for this to take effect!
当要以非root用户可以直接运行docker时，需要执行 sudo usermod -aG docker runoob 命令（每次都是）
2.启动docker后台服务
sudo service docker start
3.测试运行hello world
sudo docker run hello-world
运行结果为(可以好好读一下setps)：
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
9bb5a5d4561a: Pull complete
Digest: sha256:3e1764d0f546ceac4565547df2ac4907fe46f007ea229fd7ef2718514bcec35d
Status: Downloaded newer image for hello-world:latest Hello from Docker!
This message shows that your installation appears to be working correctly. To generate this message, Docker took the following steps:
. The Docker client contacted the Docker daemon.
. The Docker daemon pulled the "hello-world" image from the Docker Hub.
(amd64)
. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal. To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/ For more examples and ideas, visit:
https://docs.docker.com/engine/userguide/
鉴于国内网络问题，后续拉取 Docker 镜像十分缓慢，我们可以需要配置加速器来解决，我使用的是网易的镜像地址：http://hub-mirror.c.163.com。
新版的 Docker 使用 /etc/docker/daemon.json（Linux）来配置 Daemon。
请在该配置文件中加入（没有该文件的话，请先建一个）：
{
"registry-mirrors": ["http://hub-mirror.c.163.com"]
}4.15.0-20-generic