docker compose build learning process

basic grammatical structure

version: "3.8"

services: # 容器
  servicename: # 服务名字，这个名字也是内部 bridge网络可以使用的 DNS name
    image: # 镜像的名字
    command: # 可选，如果设置，则会覆盖默认镜像里的 CMD命令
    environment: # 可选，相当于 docker run里的 --env
    volumes: # 可选，相当于docker run里的 -v
    networks: # 可选，相当于 docker run里的 --network
    ports: # 可选，相当于 docker run里的 -p
  servicename2:

volumes: # 可选，相当于 docker volume create

networks: # 可选，相当于 docker network create

Take Python Flask + Redis exercise: as an example, transform it into a docker-compose file

Create a new flask-redis folder with app.py, Dockerfile

#app.py文件


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

app = Flask(__name__)
redis = Redis(host=os.environ.get('REDIS_HOST', '127.0.0.1'), port=6379)


@app.route('/')
def hello():
    redis.incr('hits')
    return f"Hello Container World! I have been seen {redis.get('hits').decode('utf-8')} times and my hostname is {socket.gethostname()}.\n"

#Dockerfile文件

FROM python:3.9.5-slim

RUN pip install flask redis && \
    groupadd -r flask && useradd -r -g flask flask && \
    mkdir /src && \
    chown -R flask:flask /src

USER flask

COPY app.py /src/app.py

WORKDIR /src

ENV FLASK_APP=app.py REDIS_HOST=redis

EXPOSE 5000

CMD ["flask", "run", "-h", "0.0.0.0"]

1. Pull the redis image

docker image pull redis

2. Pull the python image

docker pull python:3.9.5-slim

3. Enter the current folder of flask-redis and execute

docker image build -t flask-redis .

4. Enter docker image ls, there are 3 images

5. Create a network

docker network create -d bridge demo-network

6. Create the container

docker container run -d --name redis-server --network demo-network redis
docker container run -d --network demo-network --name flask-demo --env REDIS_HOST=redis-server -p 5000:5000 flask-demo

After you are familiar with this chapter, you will first build two images of flask-redis and redis, and then run two containers. But the content of the docker-compose.yml file is not used.

Create a new docker-compose.yml file

#docker-compose.yml文件

version: "3.8"

services:
  flask-redis:
    container_name: flask-redis
    image: flask-redis:latest
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    container_name: redis-latest
    image: redis:latest
    networks:
      - demo-network

networks:
  demo-network:

Then execute the docker-compose up -d command to run two containers at the same time, that is, to complete the image building and container operation directly through the docker-compose command, which is in place in one step.

6. Use the docker container rm xxx xxx command to delete the two containers created before, and keep the previous image file

7. Execute docker-compose

docker-compose up

This command is to create two containers and start them normally after you have the flask-redis image

Press ctrl+c to exit and stop.

Enter to view the container, and you can see that two containers whose status is exited are automatically created for you.

docker container ls -a

Use the command -d to run in the background instead

docker-compose up -d

But I bought this Ali server, but it cannot be opened normally through the ip address + port number.

Later, I found out that the Alibaba Cloud server I purchased was caused by the port not being opened.

You can also see it by running the docker-compose ps command

docker-compose ps

The main thing is that the docker-compose ps command must be run in the current directory.

Execute docker-compose stop to stop running

docker-compose stop

Ability to view stopped containers

Execute delete, all will be deleted

docker-compose rm

You also need to create the network just now, docker-compose will not delete it for you, you have to manually delete it yourself.

For learning reference only.

The above are based on the premise of building a flask-redis image in advance, to docker-compose

What if we don't have this mirror image? Next, by modifying the docker-compose.yml file, the flask-redis image is automatically built, and two containers are created and run normally.

For example, I have a flask-py folder, a flask folder, and docker-compose.yml. These two are at the same level.

version: "3.8"

services:
  #flask是容器名称
  flask:
    #通过build构建镜像
    build:
      context: ./flask  #构建的文件夹./flask  context意思是要的build的目录
      dockerfile: Dockerfile  # Dockerfile的名字
    image: flask:latest  #镜像的名称
    environment:
      - REDIS_HOST=redis-server
    networks:
      - demo-network
    ports:
      - 8080:5000

  redis-server:
    container_name: redis-latest
    image: redis:latest
    networks:
      - demo-network

networks:
  demo-network:

Then delete the flask-redis image created before, docker image rm xxx(id)

Then upload the flask-py folder, and then cd into it

Excuting an order