Docker Compose 2020(1)Installation and Basic

Docker Compose 2020(1)Installation and Basic

Latest Docker Compose version VS Docker version
https://docs.docker.com/compose/compose-file/

On my server, check the docker version
> docker --version
Docker version 19.03.6, build 369ce74a3c

Open my docker 2375 ports if we need
> sudo vi /usr/lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H tcp://10.132.156.80:2375 -H unix:///var/run/docker.sock -H fd:// --containerd=/run/containerd/containerd.sock
> sudo systemctl daemon-reload
> sudo systemctl restart docker

I use portainer to clean up all the images and containers and other resources.

My testing server even more up to date
> docker --version
Docker version 19.03.8, build afacb8b

If we do not have docker installed, we may use this script
> curl -sSL https://get.docker.com/ | sh

Verify if my version is cool
> docker run hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world

Check the latest version for compose https://github.com/docker/compose/releases/

Current latest version  1.25.4
> sudo curl -L https://github.com/docker/compose/releases/download/1.25.4/docker-compose-`uname -s`-`uname -m` -o /usr/local/bin/docker-compose
> sudo chmod +x /usr/local/bin/docker-compose

Check version
> docker-compose --version
docker-compose version 1.25.4, build 8d51620a

Do a simple Sample
> mkdir compose-sample
> cd compose-sample/
> mkdir src
> mkdir docker
Python source
> vi src/app.py
from flask import Flask
from redis import Redis
app = Flask(__name__)
redis = Redis(host='redis', port=6379)
@app.route('/')
def hello():
        count = redis.incr('hits')
        return 'hello, Carl. I see you {} times.\n'.format(count)
if __name__ == "__main__":
        app.run(host="0.0.0.0", debug=True)

A simple flask server increase the redis count.

Running requirement file
> vi src/requirements.txt
flask
redis

Prepare the Docker Image
> mkdir docker/web
> vi docker/web/Dockerfile
FROM python:3.4
ADD . /docker
ADD ../../src /src
WORKDIR /src
RUN pip install -r requirements.txt
CMD ["python", "app.py"]

../../src is wrong in the Dockerfile, we can fix that later.

> vi docker/docker-compose.yml
version: '3'
services:
  web:
    build: ./web/
    ports:
     - "5000:5000"
  redis:
    image: "redis:3.0.7"

Change to use volumes
version: '3'
services:
  web:
    build: ./web/
    ports:
     - "5000:5000"
    volumes:
     - ../src:/src
  redis:
    image: "redis:3.0.7"

> cat docker/web/Dockerfile
FROM python:3.4
WORKDIR /src
RUN pip install -r requirements.txt
CMD ["python", "app.py"]

Try to run that
> docker-compose up

Not working, change to this
version: '3'
services:
  web:
    build: ./web/
    ports:
     - "5000:5000"
    volumes:
     - /home/carl/work/compose-sample/src:/src
  redis:
    image: "redis:3.0.7"

Check logging
> docker ps -a
CONTAINER ID        IMAGE               COMMAND                  CREATED             STATUS                     PORTS               NAMES
f74e3bacc623        redis:3.0.7         "docker-entrypoint.s…"   8 seconds ago       Up 6 seconds               6379/tcp            docker_redis_1
85dfcacda306        docker_web          "python3"                8 seconds ago       Exited (0) 6 seconds ago                       docker_web_1

Try to start the web and check why, it seems the src is not there at all.
> docker run -it --name docker_web1 docker_web:latest /bin/bash

Adjust the directory from the example as follow:
web/Dockerfile
web/src/app.py
web/src/requirements.txt
docker-compose.yml

> docker-compose up

Visit the page, it works pretty well.
http://rancher-home:5000/

References:
https://beginor.github.io/2017/06/08/use-compose-instead-of-run.html
https://docs.docker.com/compose/compose-file/
https://blog.csdn.net/pushiqiang/article/details/78682323