Twisted in Docker

Abstract

Docker is often used in micro-services architectures. Those are based on different components communicating over a network. Twisted, with its native support for several networking paradigms, is often a good fit for Docker-based architectures. Docker, and containers in general, are new. Both the tooling and the consensus on how to use the tooling are evolving fast. We are giving here the foundations on how to use Docker, so we can build the understanding of how to use Twisted in Docker on top of it. Note that Docker is a Linux-based technology. Though other operating systems have similar facilities, Docker is built on taking advantage of specific Linux-kernel facilities. Docker for Windows does have the ability to run "Windows Containers," but this is beyond the scope of this chapter. Docker for Mac and Docker for Windows use a Virtual Machine running Linux, and have just enough integration with the host OS (OS X and Windows, respectively) to make the interaction seamless. However, it is important to remember that a Docker container is always running on a Linux kernel, even when running it on a Mac or Windows laptop. Intro to Docker Because Docker is both new and popular, several distinct things are called "Docker." Understanding exactly what Docker is itself is nontrivial. We try to break "Docker" here into distinct concepts. Note that each of these is often referred to as "Docker," as well as the whole comprising them. Containers Containers are processes that are run with more isolation than is possible in traditional UNIX processes.