The first thing to do before we dive into Celery and the other Python packages that we will explore is set up a test environment. We are developing distributed applications, which means that we ideally need a multimachine environment.

Those of you who have access to at least two machines in a properly set up network environment (meaning that these test machines have DNS-resolvable names) can skip to the next section. All the rest, please keep reading.

For those without easy access to multiple machines for development and testing, there are still a number of solutions that are easy to implement and either free or very inexpensive.

One is to simply use virtual machines running on the local host (for instance, using VirtualBox: https://www.virtualbox.org). Just create a couple of VMs, install your favorite Linux distribution on it, and keep them running in the background. Since these do not need a graphical desktop for development purposes, they can be very...