Understanding the Hubs CE Infrastructure

The product known as "Mozilla Hubs" is comprised of several powerful pieces of software. For example, when you visit a Hub with your Web browser, you are interacting with the Hubs Client. You can read the client's JavaScript source code here on GitHub.

The Hubs Client itself interacts with several other pieces of software, such as:

• Reticulum, Hubs' networking and API server
• Dialog, Hubs' WebRTC voice and video communication server

The Hubs Client, Dialog, and Reticulum are just three components of a larger stack of software. Each of those stack's components are individually configured and networked to other components in order to make Hubs work properly.

Rather than require developers to download, install, configure, connect, and update each of the stack's components individually, the Hubs team has developed the product known as "Hubs Community Edition". Hubs CE simplifies and automates most of that complex deployment process using software called Kubernetes, which is a containerized software orchestration system.

If you are already familiar with containerized software and Kubernetes, tap here to skip ahead to the "Hubs' Containerized Services" section.

Containerized Software Introduction

Consider the Web browser you are using right now to view these words:

1. Unless that browser was installed onto your device from the factory, you first had to download the version of your browser corresponding to your operating system.
2. Then, you installed the browser, perhaps specifying a directory into which its application files were placed.
3. After that, you opened the browser. Perhaps you then signed into a Firefox account, or a Google account.
4. Maybe you then installed an ad blocker extension, or a password manager.
5. You might have navigated to a website and added it to your favorites bar...

Imagine if you could package up the complete state of your Web browser installation - including its configuration settings, logged-in accounts, extensions, browser history, favorites, and more - and make use of that package on any other computer, regardless of operating system.

Similarly, imagine if you could package up the complete state of any application - including its dependencies, libraries, configuration files, and application code - and run that package on any other computer...

This is possible using open-source software called Docker. A Docker Container is a process executed on a computer that runs its own packaged and configured software. You can learn more about Docker and Docker Containers here on Docker Docs.

Many components of Hubs Community Edition run inside separate Docker Containers. By themselves, these Containers don't know much about each other. For example, if you ran the Reticulum Container on your computer, but didn't run the Dialog WebRTC communication Container, people who connected to your Hub would be able to see each other, but not hear each other.

So, we need some way for these Containers to connect to each other. We need some way for people who connect to a given Hub to also be able to connect to that Hub's associated Dialog server. We need to be able to, for example, update the Dialog container's code without bringing down the Reticulum container. How do we coordinate all of these Containers? 😵‍💫

Kubernetes!