Docker Container and Vagrant / Virtualbox 101s

Some simple recipes for getting started with running some demo virtual applications in variety of ways.

Docker and Zeit Now flaskdemo

This first demo creates a simple flask app and a Dockerfile with just enough to get it running; it runs locally if you have docker installed locally, and will also run on Zeit Now .

Create a new directory flaskdemo and create a couple of files in it, specifically:

flaskdemo.py

from flask import Flask app = Flask(__name__) @app.route('/') def hello_world(): return 'Hello, World!' if __name__ == "__main__": app.run(host='0.0.0.0', port=5005)

Dockerfile

FROM python:3.6-slim-stretch RUN pip3 install flask EXPOSE 5005 COPY ./flaskdemo.py /var/flaskdemo.py CMD ["python3","/var/flaskdemo.py"]

Download and run the Zeit Now application, then on the command line cd into the flaskdemo folder and type: now to launch the application and now ls to lookup the URL where it’s running.

If you prefer, and have docker installed locally:

on the command line, cd into the directory and then build the Docker container with the command docker build -t myflaskdemo . (the dot / . is important it says “the path to the Dockerfile is the current directory) run the container with: docker run -d -p 8087:5005 myflaskdemo and you should see a hello message on port 8087.

Compare this with what I had to do to get a flask app running via the Reclaim CPanel .

Docker demo Jupyter notebook powered API

This demo shows how to knock up an API server where the API is defined in a Jupyter notebook and published using the Jupyter Kernel Gateway (see also Building a JSON API Using Jupyter Notebooks in Under 5 Minutes ). This is probably all overkill but it make for a literate definition of your API defining code…

Create a new directory jupyterkgdemo and copy the following Jupyter notebook into it ( gist/psychemedia/jupyterkgdemo.ipynb ):

jupyterkgdemo.ipynb

Add the following Dockerfile :

FROM python:3.5-slim-stretch RUN pip3 install jupyter_kernel_gateway EXPOSE 5055 COPY ./jupyterkgdemo.ipynb /var/jupyterkgdemo.ipynb CMD ["/usr/local/bin/jupyter","kernelgateway","--ip=0.0.0.0","--KernelGatewayApp.api='kernel_gateway.notebook_http'","--KernelGatewayApp.seed_uri='/var/jupyterkgdemo.ipynb'", "--port=5055"]

With Docker installed locally:

on the command line, cd into the directory and then build the Docker container with the command docker build -t myjupyyterapidemo . (the dot / . is important it says “the path to the Dockerfile is the current directory) run the container with: docker run -d -p 8089:5055 myjupyyterapidemo and you should see a message on port 8089; go to localhost:8089/hello/whoever and you should get a message personalised to whoever .

Note that this doesn’t seem to run on Zeit Now ; another port seems to be detected that I think breaks things?

Vagrant Demo

Vagrant is a tool that helps automate the deployment of virtual machines using Virtualbox. In some senses, it’s overkill; in others, it means we don’t have to provide instructions about setting up various Virtualbox bits and bobs…

Install vagrant and then add the following files to a vagrantdemo folder:

First, the simple flask app demo code we used before:

flaskdemo.py

from flask import Flask app = Flask(__name__) @app.route('/') def hello_world(): return 'Hello, World!' if __name__ == "__main__": app.run(host='0.0.0.0', port=5005)

We can run this as a linux service inside the VM we means we need to provide a service definition file:

flaskservice.service

[Unit] Description=Demo Flask Server After=network.target [Service] Type=simple PIDFile=/run/flaskdemo.pid WorkingDirectory=/var/flaskdemo ExecStart=/usr/bin/python3 flaskdemo.py Restart=always RestartSec=10 #KillMode=mixed [Install] WantedBy=multi-user.target

To install the packages we need, and copy the local files into the correct locations inside the VM, we can define a config shell script:

flaskserver.sh

#!/usr/bin/env bash apt-get update && apt-get install -y python3 python3-dev python3-pip && apt-get clean pip3 install flask THISDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )" mkdir -p /var/flaskdemo cp $THISDIR/flaskdemo.py /var/flaskdemo/ cp $THISDIR/flaskserver.service /lib/systemd/system/flaskserver.service # Enable autostart systemctl enable flaskserver.service # Refresh service config systemctl daemon-reload systemctl restart flaskserver

Now we need a Vagrantfile to marshal the VM:

Vagrantfile

Vagrant.configure("2") do |config| config.vm.box = "bento/ubuntu-16.04" config.vm.network :forwarded_port, guest: 5005, host: 8077, auto_correct: true config.vm.synced_folder ".", "/vagrant" config.vm.provision :shell, :inline => <<-SH cd /vagrant/ source ./flaskserver.sh SH end

On the command line, cd into the folder and run vagrant up . You should be able to see the hello world on localhost:8077 .