Docker是一个轻量级的基于进程的虚拟化解决方案。简单来说，Docker是将应用程序和运行环境一起打包成一个容器，进而可以发布到其他平台上运行。
环境：Ubuntu 18.04.1 LTS
安装Docker
root@jaking-virtual-machine:~# apt-get install -y docker-engineReading package lists... Done
Building dependency tree
Reading state information... Done
...
root@jaking-virtual-machine:~# docker versionClient:
Version: 18.06.1-ce
API version: 1.38
Go version: go1.10.4
Git commit: e68fc7a Built: Fri Oct 19 19:43:14 2018
OS/Arch:linux/amd64 Experimental: falseServer:
Engine:
Version: 18.06.1-ce
API version: 1.38 (minimum version 1.12)
Go version: go1.10.4
Git commit: e68fc7a Built: Thu Sep 27 02:39:50 2018
OS/Arch: linux/amd64 Experimental: falseroot@jaking-virtual-machine:~# systemctl start dockerroot@jaking-virtual-machine:~# systemctl enable dockerSynchronizing state of docker.service with SysV service script with /lib/systemd/systemd-sysv-install.Executing: /lib/systemd/systemd-sysv-install enable docker
搜索ubuntu相关的容器
root@jaking-virtual-machine:~# docker search ubuntuNAME DESCRIPTION STARS OFFICIAL AUTOMATED
ubuntu Ubuntu is a Debian-based Linux operating sys… 8838 [OK]
dorowu/ubuntu-desktop-lxde-vnc Ubuntu with openssh-server and NoVNC 247 [OK]
rastasheep/ubuntu-sshd Dockerized SSH service, built on top of offi… 184 [OK]
consol/ubuntu-xfce-vnc Ubuntu container with "headless" VNC session… 136 [OK]
ansible/ubuntu14.04-ansible Ubuntu 14.04 LTS with ansible 95 [OK]
ubuntu-upstart Upstart is an event-based replacement for th… 92 [OK]
下载容器
root@jaking-virtual-machine:~# docker pull ubuntu-upstart
Using default tag: latest
latest: Pulling from library/ubuntu-upstart8387d9ff0016: Pull complete 3b52deaaf0ed: Pull complete 4bd501fad6de: Pull complete a3ed95caeb02: Pull complete a6dc1658c730: Pull complete 9ed623dca71b: Pull complete 998ee72febf9: Pull complete 437038dc2fba: Pull complete da0ee05a1a1d: Pull complete 1e1c3e99deb1: Pull complete 4fcc22d7b2a1: Pull complete 6c7dda5571e4: Pull complete Digest: sha256:597dfb1868012dcd04a705572dbc1542cb7598bce0eaa1c2656eb3acfc8b51d2
Status: Downloaded newer image for ubuntu-upstart:latest
查看容器的镜像
root@jaking-virtual-machine:~# docker images ubuntu-upstartREPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu-upstart latest b28219773b9b 2 years ago 253MB
从上面的结果可以看到，容器已经成功下载。利用下载的ubuntu-upstart容器，可以运行一个简单的程序，此处以“Hello Docker”为例：
root@jaking-virtual-machine:~# docker run ubuntu-upstart /bin/echo Hello DockerHello Docker
还可以使用其他容器，如使用ubuntu作为容器，下载操作如下：
root@jaking-virtual-machine:~# docker pull ubuntu
Using default tag: latest
latest: Pulling from library/ubuntu
32802c0cfa4d: Pull complete
da1315cffa03: Pull complete
fa83472a3562: Pull complete
f85999a86bef: Pull complete
Digest: sha256:6d0e0c26489e33f5a6f0020edface2727db9489744ecc9b4f50c7fa671f23c49
Status: Downloaded newer image for ubuntu:latest
root@jaking-virtual-machine:~# docker images ubuntu
REPOSITORY TAG IMAGE ID CREATED SIZE
ubuntu latest 93fd78260bd1 10 days ago 86.2MB
Docker的容器操作
当Docker中包含了容器，就如同虚拟机中安装了操作系统一样，可以运行、安装软件、做一些设置。现在就可以运行之前下载的ubuntu:
root@jaking-virtual-machine:~# docker run -i -t ubuntu /bin/bash
运行一个名为ubuntu的容器#i选项表示捕获标准输入和输出；t选项表示分配的终端和控制台root@05559b460591:/# root@05559b460591:/# uname -aLinux 05559b460591 4.15.0-36-generic #39-Ubuntu SMP Mon Sep 24 16:19:09 UTC 2018 x86_64 x86_64 x86_64 GNU/Linuxroot@05559b460591:/# exit#退出容器exit
root@jaking-virtual-machine:~# docker psCONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
从上面的命令可以看到，使用run命令运行了一个容器，但退出之后容器也关闭了，这不是想要的结果。这时可以使用选项d让容器一直在后台运行：
root@jaking-virtual-machine:~# docker run -d -i -t ubuntu /bin/bash
b19cc95aef9cb6f402062915b527864cf045debc65dbabd23a495cea32a138dd
root@jaking-virtual-machine:~# docker ps -a
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
b19cc95aef9c ubuntu "/bin/bash" 15 seconds ago Up 14 seconds kind_johnson05559b460591 ubuntu "/bin/bash" 35 minutes ago Exited (0) 9 minutes ago xenodochial_hypatia5bc78fd29b2a ubuntu-upstart "/bin/echo Hello Doc…" 42 minutes ago Exited (0) 42 minutes ago silly_jenningsc54bb6d664b7 ubuntu-upstart "/bin/echo Hello Doc…" 44 minutes ago Exited (0) 44 minutes ago jolly_thompson
从上面的命令输出可以看到一个ID为b19cc95aef9c的容器正在运行，这个ID号就是操作此容器的重要参数。
容器运行在后台时，可以使用attach登录正在运行的容器：
root@jaking-virtual-machine:~# docker attach b19cc95aef9croot@b19cc95aef9c:/# exit
exit
root@jaking-virtual-machine:~#
容器的操作还有很多命令，常用的操作还有：
docker cp :将容器中的文件复制到主机上docker rm:删除一个容器docker port:配置容器的端口转发docker start:启动一个容器docker stop:停止一个容器docker top:显示容器中的进程docker ps:列出容器docker logs:获取容器的日志除了以上这些操作外，Docker还有许多操作，可自行阅读相关文档了解。
