Infra

Vagrant You put code into environments Run provisioning script onto VM => installs correct software (node.js version, user permissions, config)

Docker You build your environment and can run it anywhere Runs off of containers. Dockerfile builds a docker image. Docker image: complete app code that will sit on top of a machine (you don't store the machine on the image) Run docker image in a container. Push that image to Docker Hub (or others) Any other machine can run your IMAGE. [docker run myProjectImage] -> Since the image contains the entire image you don't need to install any software on that new machine -> In other words, no need to install npm, node.js, etc. -> Cloud Clusters: All the computers to act as one; share resources. Spin up containers all run in the cluster. nginx: Can spin up an nginx container and load balance the containers and provide a port to allow one to access the app.

Python & Docker Docker container interacts directly with host kernel. Spin up more processes? Spin up more containers. Docker host? The image contains everything (code, modules, dependencies, etc.) Docker build: Dependencies, nginx, wsgi, etc. Docker run: Makes instance of the app, creates a container (running instance of the app) Docker engine. Call the Dockerfile.

FROM python:3.4

# Set PYTHONUNBUFFERED so output is displayed in the Docker log
# Helps out put logs in console
ENV PYTHONUNBUFFERED=1

# app (service) is exposed on port 8000
EXPOSE 8000
# here is the location of the django app itself 
WORKDIR /usr/src/app

# Install dependencies
# takes req.txt and copies it into the Docker image 
COPY requirements.txt requirements.txt 
RUN pip install -r requirements.txt

# Copy the rest of the application's code
# copy all the source code 
COPY . /usr/src/app

# Run the app: run django migrations & runserver
# not good for production practices. 
CMD ["./run_app.sh"]

Docker build -t nameApp # -t: tag Docker image with a name Container: chained images