Init systems

OpenRC is a service manager that executes system services and manages service dependencies on startup and shutdown. It is commonly used in lightweight Linux distributions like Alpine Linux, and is a core component of systems designed for simplicity and speed. OpenRC scripts are often written in shell script format and are stored in /etc/init.d/, the standard location for init scripts.

The BusyBox init system is a lightweight, minimalist alternative to traditional Linux init systems such as SysVinit or systemd. Designed primarily for embedded systems, BusyBox provides a comprehensive set of utilities in a single executable, making it ideal for resource-constrained environments like those found in Buildroot and Yocto projects. One of its key components is its init system, which is responsible for starting and stopping system services at boot and shutdown.

A systemd service is a unit configuration file that defines how a specific service should be started, stopped, and managed by the systemd system and service manager

The init system is the first process that runs when a Linux kernel boots. It sets up the environment, manages system services, and handles the launch of user-space processes. Different init systems offer varying features, such as parallel service startup, dependency management, and system monitoring.