How to beat Santa Claus

Nobody beats Santa Claus at logistics, also known as Papá Noel, or Viejito Pascuero in Chile. I mean, who else could deliver presents to every child in the world in one night? Sure, he has twenty-four hours to do it, but even so, to cover each time zone he has barely sixty minutes to land on every house, drop off the presents and take off again.

The trick is that Santa Claus uses magic, so there is little we can do about it. Until we reach that level of technological development we won’t be able to beat him.

Clarke’s third law says:

“Any sufficiently advanced technology is indistinguishable from magic”.

So the question is whether we have technology in this world that looks like magic.

Of course we have several. Think of Google. When you search for something on that service, how can it possibly find, so fast, what we need in such a vast amount of information?

It is the magic of a technology known as Information Retrieval, without which we could not have that miracle of modern society, the search engine¹.

In IT we have developed several kinds of magic, sorry, technologies that are astonishing. Technologies that, just like the Viejito Pascuero, are capable of bringing joy, or at least emotions (of all kinds).

Have you ever thought about how Netflix works?

Maybe Netflix is an example of how close we are to reaching Santa Claus’s magic.

Think about this: every minute hundreds of thousands of people press play on some device to watch a movie or TV series, the one they want to watch, the one that best fits their tastes, and on top of that they enjoy it in great quality and without technical interruptions.

How is it possible that I can watch the same movie on my phone, computer, TV or tablet without the image quality seeming to degrade?

The answer to that and other questions raised by the way Netflix works comes from a brilliant and innovative software architecture.

Microservices

Suppose you develop a website. It will have several features: user registration; if it is a commercial site then it needs a payment module and a billing one; it will probably have notifications; and the site’s own functionality: if it is a sales site, you’ll have the catalog, the shopping cart, etc.

But what happens if you have to modify the payment module? Most likely, to deploy the change you’ll have to interrupt the whole service. Can you imagine Netflix doing that?

Doesn’t it bother you when your bank tells you it will be “under maintenance” all weekend? What happens is that traditional applications, like the one I just described, or your bank’s website, are “monolithic applications”.

A change in one part of the system impacts all the rest, even if some modules don’t have much to do with each other. To make a change you have to stop the whole machine and be very careful not to break anything in the process, and that takes a lot of time.

So, how do you ensure continuous change, with no interruptions to your web service?

The key is a software development model called Microservices Architecture. Amazon and Netflix have been pioneers in developing this architectural paradigm.

Netflix is not actually a monolithic site. Even though we get the impression that it is just one big application, in reality Netflix is made up of the aggregation of more than seven hundred microservices, each one handling a specific piece of the system’s functionality.

There is a microservice in charge of billing, another one that charges your credit card, another shows a list of recently added movies, another shows the list of movies personalized to your taste, a list that was computed by several other microservices that analyze data on your behavior and try to predict your tastes. There are microservices in charge of figuring out which device you are using and picking the right format for your screen at that moment.

But there are services all along the production chain. When Netflix acquires or produces a movie, or series, it receives the original in digital format and stores it in its storage centers in the cloud. There are microservices in charge of “transcoding” that digital content into different versions. Netflix supports thousands of different devices, with different resolutions and playback speeds, and each movie is transformed so that it can be viewed correctly on each device. Of course, each copy is processed with a DRM (Digital Rights Management) algorithm to make sure the content isn’t pirated.

On top of that, you have to guarantee that the content reaches each viewer at the right speed. To achieve this, these files are distributed across what is known as a Content Delivery Network (CDN). A network of servers that store these pre-encoded copies of the videos, located in different geographic places as close as possible to the internet providers².

Originally Netflix used CDN services from companies like Akamai, but over time it had to develop its own content network, called Open Connect. It is as if Netflix handed out hard drives around the world to every internet provider, with copies of the movies it expects to stream in those places.

Sometimes when we start watching a movie on Netflix it looks a bit blurry for the first few seconds. At that moment the Netflix client is trying to figure out which is the closest CDN node that holds the movie we are watching. Once that is settled it can guarantee a constant transfer rate.

Besides, every device contains a piece of software that knows how to adapt the content to the resolution and speed of the machine we are using to watch. Many versions of this software have to be maintained, for every Smart TV, smartphone, computer or browser on the market.

This whole choreography of microservices, networks, applications and infrastructure is the closest thing I can think of to Santa’s magic. So I’m sure that some day we’ll be able to match him.

All I’d wish for this Christmas, dear Santa Claus, is that so many other services would learn from these architectures and implement them on their websites. We would all be so happy!

It has been an intense, interesting year, in which I have tried to bring you more content that is relevant and interesting to all of you. I hope you are enjoying the holidays with your loved ones. I promise that in 2018 you’ll get a lot more of La Naturaleza del Software

Merry Christmas!