After I went though this tutorial

how to setup an app with redis with docker-compose

https://docs.docker.com/compose/gettingstarted/#step-3-define-services-in-a-compose-file

1. go through the tutorial on the above link
2. run docker-compose up That's it.

NOTE:

1. docker-compose automatically links the redis with the app services accessing port '6379', which is the default exposed port of redis.
2. the redis container created through this process can NOT be accessed by other containers outside of services defined in docker-compose. (docker: Error response from daemon: Cannot link to /playarounddocker_redis_1, as it does not belong to the default network)

how to setup an app with redis without docker-compose

https://docs.docker.com/get-started/part2/#build-the-app (start point is app.py)

1. cd app
2. run docker build -t docker-init ., which build an image based on Dockerfile, and Dockerfile uses app.py as an entry point
3. run docker pull redis to get redis image
4. run docker run --name redis -p 6379:6379 redis to create a container of reids. DO NOT forget to config the port!!!
5. run docker run --name hello-redis-3 --link redis -p 4040:80 docker-init, create a container of our app and link it to redis (NOTE: you have to link the redis container here. Different containers may expose same port number, so define the redis port in app.py isn't sufficient)
6. open link http://localhost:4040/ in browser

how to remove all containers / images

Delete all containers

docker rm $(docker ps -a -q)

Delete all images

docker rmi $(docker images -q)