Docker容器
一：什么是容器
如果容器理解为独立运行的一个或一组应用，以及它们的运行态环境。 而虚拟机则为可理解为跑在上面的应用。
二：创建容器
创建文件名为Dockerfile的空目录，将以下三个文件复制到其中。
1.添加文件
Dockerfile文件
# 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"]
# Set proxy server, replace host:port with values for your servers
ENV http_proxy host:port
ENV https_proxy host:port
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)
2.创建镜像
查看文件
#ls
Dockerfile app.py requirements.txt
在“Dockerfile”文件夹下运行下面命令，创建了一个以“friendlyhello”命名的Docker镜像。
#docker build -t friendlyhello .
3.查看新建镜像
新建的镜像在Docker 镜像registry中
#docker images
REPOSITORY TAG IMAGE ID
friendlyhello latest 326387cea398
4.运行应用程序
运行该APP(应用程序)，并将4000映射到80端口
#docker run -p 4000:80 friendlyhello
并在浏览器中输入http://localhost:4000，注意如果是win7则将localhost修改为IP
5.后台运行应用程序
#docker run -d -p 4000:80 friendlyhello
6.查看容器
# docker container ls
CONTAINER ID IMAGE COMMAND CREATED
1fa4ab2cf395 friendlyhello "python app.py" 28 seconds ago
7.停止容器
#docker container stop 1fa4ab2cf395
三：分享镜像
1.登录Docker
登录到本地计算机上公共的Docker注册表。如果没有账号，可以登录到https://cloud.docker.com/中注册
#docker login
2.标记镜像
形如docker tag image username/repository:tag，意思是用户john将镜像“ friendlyhello”上传至“get-started”存储库，标记为“part2”。
#docker tag friendlyhello john/get-started:part2
3. 查看镜像
# docker images
4.发布镜像
形如“docker push username/repository:tag”，镜像一旦上传将会被公开
#docker push john/get-started:part2
5.取出镜像
输入形如“docker run -p 4000:80 username/repository:tag”如下命令
#docker run -p 4000:80 john/get-started:part2
返回如下：
Unable to find image 'john/get-started:part2' locally
part2: Pulling from john/get-started
10a267c67f42: Already exists
f68a39a6a5e4: Already exists
9beaffc0cf19: Already exists
3c1fe835fb6b: Already exists
4c9f1fa8fcb8: Already exists
ee7d8f576a14: Already exists
fbccdcced46e: Already exists
Digest: sha256:0601c866aab2adcc6498200efd0f754037e909e5fd42069adeff72d1e2439068
Status: Downloaded newer image for john/get-started:part2
* Running on http://0.0.0.0:80/ (Press CTRL+C to quit)
四：附录：
如果想知道更多容器相关命令可试着运行下列命令
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 container ls # List all running containers
docker container ls -a # List all containers, even those not running
docker container stop <hash> # Gracefully stop the specified container
docker container kill <hash> # Force shutdown of the specified container
docker container rm <hash> # Remove specified container from this machine
docker container rm $(docker container ls -a -q) # Remove all containers
docker image ls -a # List all images on this machine
docker image rm <image id> # Remove specified image from this machine
docker image rm $(docker image ls -a -q) # Remove all images from this machine
docker login # Log in this CLI session using your Docker credentials
docker tag <image> username/repository:tag # Tag <image> for upload to registry
docker push username/repository:tag # Upload tagged image to registry
docker run username/repository:tag # Run image from a registry
