Processes and services
Let’s talk about the subtle difference between processes and services. You can think of a service as some packaging around a piece of software that makes it easier to manage as a running process.
A service adds convenient features to how a program (and the resulting process spawned by that program) is handled by the system. For example, it lets you define dependencies between different processes, control startup order, add environment variables for the process to start with, limit resource usage, control permissions, and many other useful things. To tie a bow around the whole package, a service provides a simple name to reference your program. We’ll show you how to create your own service in the later Chapter 10, Configuring Software.
In the rest of this chapter, we’ll stick to managing existing services.
