Docker 快速入门

Docker 入门

Docker是.......

快速上手

1. 安装

以MacOS为例, 其余操做系统的docker安装与运行,请绕道至 Docker官网

下载地址:

MacOS的Docker安装包地址

而后dmg文件安装便可.

运行

和其余软件同样, 运行Docker便可

2. 登入帐号

在 docker.io 上面注册你我的的帐号, 用于建立同步你我的的容器镜像

回到本机, 咱们使用命令行登入便可

docker login
## 后续根据提示,输入你的帐号密码登入

3. 简单命令

官方给出了一个示例命令

docker run hello-world

运行结果以下:

控制打印了一段说明文字

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
    (amd64)
 3. The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 4. 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://cloud.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/

大体介绍了 docker run xxxx 命令后,docker内部帮我完成的后续工做

4. 建立容器 (Container)

官网给出了一个docker运行python的web应用的demo. 详细步骤以下:

1. 建立一个工做目录

# 我根据我的代码习惯, 建立了以下目录, (其实咱们只须要一个新的有操做权限的目录空间)
mkdir -p ~/code/docker/demo-python
cd ~/code/docker/demo-python

2. 建立Dockerfile文件

# 切换到工做目录
cd ~/code/docker/demo-python

# 建立 Dockerfile
touch Dockerfile

vim Dockerfile
# 编辑文件 Dockerfile 内容以下

Dockerfile

# Use an official Python runtime as a parent image
FROM python:2.7-slim

# Set the working directory to /app
WORKDIR /app

# Copy the current directory contents into the container at /app
ADD . /app

# Install any needed packages specified in requirements.txt
RUN pip install --trusted-host pypi.python.org -r requirements.txt

# Make port 80 available to the world outside this container
EXPOSE 80

# Define environment variable
ENV NAME World

# Run app.py when the container launches
CMD ["python", "app.py"]

3. 增长python栈的Web服务代码

在工做目录下建立 requirements.txt 和 app.py

requirements.txt

Flask
Redis

app.py

from flask import Flask
from redis import Redis, RedisError
import os
import socket

# Connect to Redis
redis = Redis(host="redis", db=0, socket_connect_timeout=2, socket_timeout=2)

app = Flask(__name__)

@app.route("/")
def hello():
    try:
        visits = redis.incr("counter")
    except RedisError:
        visits = "<i>cannot connect to Redis, counter disabled</i>"

    html = "<h3>Hello {name}!</h3>" \
           "<b>Hostname:</b> {hostname}<br/>" \
           "<b>Visits:</b> {visits}"
    return html.format(name=os.getenv("NAME", "world"), hostname=socket.gethostname(), visits=visits)

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=80)

4. 构建

# -t 参数为 指定tagname
docker build -t demopython .

# 查看刚构建的镜像
docker images

5. 运行

# -p 参数: 使用本机4000端口映射容器中80端口服务
docker run -p 4000:80 demopython

6. 访问服务

打开浏览器访问服务 http://localhost:4000