入门-container-最底层入门-container-最底层

最底层是container，第二层是service，最高层是stack。
前提

dockers version:1.13或者更高(17.03.1-ce)

用Dockerfile定制container
dockerfile定义了container的环境里面的内容。在container里面的资源(如网络接口和磁盘驱动)都是虚拟的，和物理机分离的，所以必须映射端口、指定要copy的文件。
创建一个空目录，创建一个Dockerfile文件。

# Use an official python runtime as a base 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 -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"]

需要在container中运行的App
在Dockerfile的同级目录中添加两个文件：requirements.txt和app.py。
【入门-container-最底层】Dockerfile中的ADD命令将这两个文件存放在image中，EXPOSE命令可以让我们通过HTTP访问。
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 = "cannot connect to Redis, counter disabled"html = "Hello {name}! " \ "Hostname: {hostname} " \ "Visits: {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)

在一个container中获取hostname得到的是container ID。

构建这个app

docker build -t friendlyhello .

运行app

docker run -p 4000:80 friendlyhellodocker run -d -p 4000:80 friendlyhellodocker psdocker stop 1fa4ab2cf395

分享image

A registry is a collection of repositories, and a repository is a collection of images.

登陆docker id docker login
给image打标签本地image和一个registry中的一个repository建立联系的标记为username/repository:tag。
docker tag friendlyhello john/get-started:part1
发布image docker push username/repository:tag
从远程仓库获取image docker run -p 4000:80 username/repository:tag

在构建和运行image的时候，如果没有指定:tag，将会使用:latest。运行的时候如果没有tag则运行:latest的版本(不见得是最新的版本)。

docker build -t friendlyname .# Create image using this directory's Dockerfile docker run -p 4000:80 friendlyname# Run "friendlyname" mapping port 4000 to 80 docker run -d -p 4000:80 friendlyname# Same thing, but in detached mode docker ps# See a list of all running containers docker stop# Gracefully stop the specified container docker ps -a# See a list of all containers, even the ones not running docker kill# Force shutdown of the specified container docker rm# Remove the specified container from this machine docker rm $(docker ps -a -q)# Remove all containers from this machine docker images -a# Show all images on this machine docker rmi # Remove the specified image from this machine docker rmi $(docker images -q)# Remove all images from this machine docker login# Log in this CLI session using your Docker credentials docker tag username/repository:tag# Tag for upload to registry docker push username/repository:tag# Upload tagged image to registry docker run username/repository:tag# Run image from a registry