Starting and Stopping Services
A service, also called a daemon, is a running program or a process that provides a particular function. Your Linux server's primary job is to offer services. As a Linux server administrator, one of your primary jobs is managing these services.
The cupsd daemon is an example of a service your Linux server can provide. This service is responsible for printing and is covered in Chapter 16, “Configuring a Print Server.”
How do you start the cupsd daemon? How do you stop it? How do you get it to be started at system boot time? What if you have a special program you want to start on your server? How do you get it to start at boot time? All these questions and more will be answered in this chapter. Soon, you will have an excellent grasp on managing these services.
In order to understand service management, you need to understand the init daemon. The init daemon can be thought of as the “mother of all processes.” This daemon is the first process to be started by the kernel on the Linux server. The Linux kernel has a process ID (PID) of 0. Thus, the init daemon has a parent process ID (PPID) of 0, and a PID of 1. Once started, init is responsible for spawning (launching) processes configured to be started at the ...