什么是Docker？我个人理解：轻量化虚拟，属于Liunx容器的一种封装，将程序和依赖放入Docker容器中运行，虚拟环境，隔离跑。
Docker的安装
举个常见的例子：mac系统下使用homebrew进行安装
只需要输入：~$ brew cask install docker 就可以了，效果如下。
$ brew cask install docker
==> Creating Caskroom at /usr/local/Caskroom
==> We'll set permissions properly so we won't need sudo in the future
Password: # 输入 macOS 密码
==> Satisfying dependencies
==> Downloading https://download.docker.com/mac/stable/21090/Docker.dmg
######################################################################## 100.0%
==> Verifying checksum for Cask docker
==> Installing Cask docker
==> Moving App 'Docker.app' to '/Applications/Docker.app'.
🍺 docker was successfully installed!个人看来Docke核心有三部分：镜像（images）、容器（container）、仓库（registry）。
三者之间的关系：复制镜像可生成Docker容器，同一镜像Docker容器相同，仓库中可存放多个镜像,根据需求pull。
镜像可自定义（dockerfile：用于生成自定义镜像 ，可自行深入了解一下）
Docker安装完之后可配置下镜像加速，我配置的是网易的：找到鲸鱼小图标，点击选择preference->Daemon->registry mirrors中配置镜像加速路径:http://hub-mirror.c.163.com->Apply&Restart就可以了
Docker客户端：
~$ docker
~$ docker help
~$ docker stats --help
Usage: docker stats [OPTIONS] [CONTAINER...]
Display a live stream of container(s) resource usage statistics
Options:
-a, --all Show all containers (default shows just running)
--format string Pretty-print images using a Go template
--no-stream Disable streaming stats and only pull the first result
--no-trunc Do not truncate output常见的命令：
命令 | 作用 |
~$ docker version或~$ docker info | 查看版本或信息 |
~$ docker run ubuntu:15.10 /bin/echo "hi,baby" | 以ubuntu15.10为镜像创建docker容器，然后在该容器中run，输出“hi,baby” |
~$ docker run -i -t ubuntu:15.10 /bin/bash root@48f72bd6af73:/# cat /proc/versio | 运行容器交互 |
~$docker stop 容器Id | 终止容器 |
~$ docker stop 容器名 | 终止容器 |
- ubuntu:15.10指定要运行的镜像，Docker首先从本地主机上查找镜像是否存在，如果不存在，Docker 就会从镜像仓库 Docker Hub下载公共镜像。
- -t:在新容器内指定一个伪终端或终端。-i:允许你对容器内的标准输入 (STDIN) 进行交互。
- root@48f72bd6af73:/# cat /proc/version(在容器中运行命令 cat /proc/version和ls分别查看当前系统的版本信息和当前目录下的文件列表）注意：cat后面加空格，不然会出现No such file or directory)
一个web测试：
~$ docker pull training/webapp （载入镜像）
docker容器中运行一个 Python Flask 应用然后运行一个web应用：
parkin@parkindeMacBook-Air:~$ docker pull training/webapp
Using default tag: latest
latest: Pulling from training/webapp
e190868d63f8: Downloading
909cd34c6fd7: Downloading
0b9bfabab7c1: Downloading
a3ed95caeb02: Downloading
10bbbc0fc0ff: Downloading
fca59b508e9f: Downloading
e7ae2541b15b: Downloading
9dd97ef58ce9: Downloading
a4c1b0cb7af7: Downloading
latest: Pulling from training/webapp
e190868d63f8: Pull complete
909cd34c6fd7: Pull complete
0b9bfabab7c1: Pull complete
a3ed95caeb02: Pull complete
10bbbc0fc0ff: Pull complete
fca59b508e9f: Pull complete
e7ae2541b15b: Pull complete
9dd97ef58ce9: Pull complete
a4c1b0cb7af7: Pull complete
Digest: sha256:06e9c1983bd6d5db5fba376ccd63bfa529e8d02f23d5079b8f74a616308fb11d
Status: Downloaded newer image for training/webapp:latest~$ docker run -d -P training/webapp python app.py
注意：-P必须是大写，小写不对，-d:让容器在后台运行。-P:将容器内部使用的网络端口映射到我们使用的主机上。）
错误的：（-p小写）
parkin@parkindeMacBook-Air:~$ docker run -d -p training/webapp python app.py
docker: invalid publish opts format (should be name=value but got 'training/webapp').
See 'docker run --help'.
正确的：（-P大写）
parkin@parkindeMacBook-Air:~$ docker run -d -P training/webapp python app.py 7360aa21c5e4076abc82b6858d4433ff87ff296452b5ef602fe8c22b78cf896
parkin@parkindeMacBook-Air:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
17360aa21c5e training/webapp "python app.py" 18 seconds ago Up 16 seconds 0.0.0.0:32768->5000/tcp ecstatic_mccarthy~$ docker ps （查看正运行的容器）
Docker 开放了 5000 端口（默认 Python Flask 端口）映射到主机端口 32768 上,访问127.0.0.1:32768会显示“Hello world！”。
parkin@parkindeMacBook-Air:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
17360aa21c5e training/webapp "python app.py" 18 seconds ago Up 16 seconds 0.0.0.0:32768->5000/tcp ecstatic_mccarthy~$ docker ps -l （查看最后一次创建的容器）
parkin@parkindeMacBook-Air:~$ docker ps -l
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cae0bfc03bfe training/webapp "python app.py" 21 seconds ago Up 19 seconds 0.0.0.0:7777->5000/tcp goofy_elgamal~$ docker run -d -p 5000:5000 training/webapp python app.py （修改端口）
注意：修改端口时 -p是小写，再次强调小写。
parkin@parkindeMacBook-Air:~$ docker run -d -p 7777:5000 training/webapp python app.py
cae0bfc03bfe972c31fddeee5f7dcfdb3e883bbb3c8ec31a01e61cb8819af340
parkin@parkindeMacBook-Air:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cae0bfc03bfe training/webapp "python app.py" 9 seconds ago Up 8 seconds 0.0.0.0:7777->5000/tcp goofy_elgamal
edcc4ba9f383 training/webapp "python app.py" 31 minutes ago Up 21 minutes 0.0.0.0:5000->5000/tcp admiring_germain
17360aa21c5e training/webapp "python app.py" 39 minutes ago Up 39 minutes 0.0.0.0:32768->5000/tcp ecstatic_mccarthy~$ docker port 容器id或者名字（web应用容器ID或名字查看容器端口映射）
parkin@parkindeMacBook-Air:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
edcc4ba9f383 training/webapp "python app.py" 14 seconds ago Up 13 seconds 0.0.0.0:5000->5000/tcp admiring_germain
17360aa21c5e training/webapp "python app.py" 8 minutes ago Up 8 minutes 0.0.0.0:32768->5000/tcp ecstatic_mccarthy
parkin@parkindeMacBook-Air:~$ docker port edcc4ba9f383
5000/tcp -> 0.0.0.0:5000
parkin@parkindeMacBook-Air:~$ docker port admiring_germain
5000/tcp -> 0.0.0.0:5000
parkin@parkindeMacBook-Air:~$ docker port 17360aa21c5e
5000/tcp -> 0.0.0.0:32768~$ docker logs -f id或者名字（查看web应用程序日志）
-f: 让 docker logs 输出容器内部的标准。应用程序使用的是 5000 端口和应用程序的访问日志。
parkin@parkindeMacBook-Air:~$ docker logs -f 17360aa21c5e
* Running on http://0.0.0.0:5000/ (Press CTRL+C to quit)
172.17.0.1 - - [14/Mar/2019 05:23:59] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:23:59] "GET /favicon.ico HTTP/1.1" 404 -
172.17.0.1 - - [14/Mar/2019 05:30:27] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:28] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:28] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:28] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:29] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:29] "GET / HTTP/1.1" 200 -
172.17.0.1 - - [14/Mar/2019 05:30:49] "GET / HTTP/1.1" 200 -
^C~$ docker top 名字（查看web应用程序进程）
parkin@parkindeMacBook-Air:~$ docker top admiring_germain
PID USER TIME COMMAND
3602 root 0:00 python app.py
parkin@parkindeMacBook-Air:~$ docker inspect~$ docker inspect 名字（docker inspect查看docker底层信息）
JSON 文件记录 Docker 容器的配置和状态信息
{
"Id": "edcc4ba9f383daac707a62d4f8bede9a6a818c99aa9639daa4db5492629e5c1d",
"Created": "2019-03-14T05:29:54.4430641Z",
"Path": "python",
"Args": [
"app.py"
],
"State": {
"Status": "running",
"Running": true,
"Paused": false,
...,
}
}
]~$ docker stop 名字（停止应用程序）
parkin@parkindeMacBook-Air:~$ docker stop admiring_germain
admiring_germain~$ docker start 名字（重启应用程序）
parkin@parkindeMacBook-Air:~$ docker start admiring_germain
admiring_germain~$ docker rm 名字（移除应用程序）
注意：移除容器的时候必须先停止容器，否则会报错。
未关闭：
parkin@parkindeMacBook-Air:~$ docker rm admiring_germain
Error response from daemon: You cannot remove a running container edcc4ba9f383daac707a62d4f8bede9a6a818c99aa9639daa4db5492629e5c1d. Stop the container before attempting removal or force remove
已关闭：
parkin@parkindeMacBook-Air:~$ docker stop admiring_germain
admiring_germain
parkin@parkindeMacBook-Air:~$ docker rm admiring_germain
admiring_germain
parkin@parkindeMacBook-Air:~$ docker ps
CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES
cae0bfc03bfe training/webapp "python app.py" 28 minutes ago Up 28 minutes 0.0.0.0:7777->5000/tcp goofy_elgamal
17360aa21c5e training/webapp "python app.py" About an hour ago Up About an hour 0.0.0.0:32768->5000/tcp ecstatic_mccarthy
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