Vagrant, VirtualBox, & Docker Lab

This lab will show you how to use Vagrant, VirtualBox, and Docker to automate the creations of development environments. As an example, it creates a Python / Flask / Redis development environment using Vagrant and VirtualBox to set up the Python development environment, and Docker to set up the Redis server.

By creating a Vagrantfile for all of your projects, you can provide developers with an "Instant Development Environment" the runs the same on their machine as every other machine eliminating the excuse "It Works on My Machine!"

Instant Development Environment

This all each developer needs to do to get a consistent development environment to code, debug, and test with:

    git clone https://github.com/rofrano/lab-vagrant.git
    cd lab-vagrant
    vagrant up

Note: Apple M1 Chip Owners

If you are lucky enough to have a new 2020 Mac with the Apple M1 chip which is based on ARM architecture, you CANNOT use VirtualBox because VirtualBox requires an Intel architecture processor to run.

The good news is that Docker has introduced the Docker Desktop for Apple silicon that runs Docker on Macs that have the Apple M1 chip. By using Docker as a provider for Vagrant, we can simulate the same experience as developers using Vagrant with VirtualBox.

To use Docker as your provider use:

vagrant up --provider=docker

This will use a Docker image that I have prepared for use with Vagrant. You can do this even if you are on an Intel Mac providing you have Docker installed. If you get an error that Docker is not running, don't forget to start Docker and run the command again.

Additions to Vagrantfile

The following additions were made to the Vagrantfile to auto provision a complete development environment:

Forward ports from vm to host

Our Python Flask apps listens on port 5000 by default so we need to forward the port from inside the VM to our workstation so that we can access it with our browser.

    config.vm.network "forwarded_port", guest: 5000, host: 5000, host_ip: "127.0.0.1"

Control the vm memory and cpus

Python Flask is very light weight and should only need a minimal VM.

    config.vm.provider "virtualbox" do |vb|
      vb.memory = "512"
      vb.cpus = 1
    end

Set up development environment

Installing all of the dependencies with Vagrant ensures that everyone gets the same environment configured exactly the same way every time.

  config.vm.provision "shell", inline: <<-SHELL
    # Update and install
    apt-get update
    apt-get install -y vim git tree python3-dev python3-pip python3-venv apt-transport-https
    apt-get upgrade python3
    apt-get -y autoremove

    # Create a Python3 Virtual Environment and Activate it in .profile
    sudo -H -u vagrant sh -c 'python3 -m venv ~/venv'
    sudo -H -u vagrant sh -c 'echo ". ~/venv/bin/activate" >> ~/.profile'
    
    # Install app dependencies in virtual environment as vagrant user
    sudo -H -u vagrant sh -c '. ~/venv/bin/activate && pip install -U pip && pip install wheel'
    sudo -H -u vagrant sh -c '. ~/venv/bin/activate && cd /vagrant && pip install -r requirements.txt'    
  SHELL

Provision Docker containers for Redis

Vagrant supports Docker natively so let's take advantage of that and provision our Redis database using Docker.

    config.vm.provision "docker" do |d|
      d.pull_images "redis:alpine"
      d.run "redis:alpine",
        args: "--restart=always -d --name redis -h redis -p 6379:6379 -v redis_data:/data"
    end

Run the Application

Once you have used vagrant up to start the vm use:

    vagrant ssh
    cd /vagrant
    python app.py

You should now be able to test the application with the following URL:

localhost:5000/hits

Every time you access the URL the counter should increase by one.