hello-python-docker

Sample of a Python webapp dockerized as decribed in https://docs.docker.com/get-started/part2/.

The dockefile creates an images which is based on python:2.7-slim and runs a simple web app the uses the Flask framework to run. Port 80 is exposed to make the web app available to the world outside the container.

The application code is located in the file app.py. The dependencies are listed in file requirements.txt.

The events like startup and visit count are logged to the file app.log inside the container for testing purposes.

Build the image

To build the image use docker build --tag=hello-python .

Use docker image ls to see the image in your local repository.

Build and run the container

To run the app in a container in background and make it available at port 4000 at your local machine (e.g. http://localhost:4000/) use docker run -d -p 4000:80 hello-python.

Use docker ps or docker ls or docker ls -a to explore the containers in your system. Use docker start <container id> to start a container. Use docker stop <container id> to stop a container.

The image is also published at https://cloud.docker.com/repository/docker/ashburnere/hello-python-docker.

Use docker run -d -p 4000:80 ashburnere/hello-python-docker:v1 if you want to run the app directly from the image from the docker repository.

Useful Docker commands

Here is a list of useful Docker commands:

Docker basics

docker build -t <container id|name> . # Create image using the current directory's Dockerfile
docker run -p 4000:80 <container id|name> # Run the container with the given name or ID with mapping port 4000 to 80
docker run -d -p 4000:80 <container id|name> # 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 for upload to registry
docker push username/repository:tag # Upload tagged image to registry
docker run username/repository:tag # Run image from a registry
docker start <container id|name> # Start container
docker stop <container id|name> # Stop container
docker exec -it <container id|name> /bin/sh # Open shell in running container
docker rmi <image> # Remove image with name
docker container logs -f <container id|name> # View the logs of the given container

Docker services

docker stack ls # List stacks or apps
docker swarm init # Initialze docker swarm
docker stack deploy -c <composefile> <appname> # Run the specified Compose file
docker service ls # List running services associated with an app
docker service ps <service> # List tasks associated with an app
docker inspect <task or container> # Inspect task or container
docker container ls -q # List container IDs
docker stack rm <appname> # Tear down an application
docker swarm leave --force # Take down a single node swarm from the manager