Systemd is an open-source system and service manager for Linux and other Unix-like operating systems. It is designed to be a drop-in replacement for the init system traditionally used in Unix-like operating systems. It provides a standard process for controlling, configuring, and managing system services. Systemd's primary purpose is to manage the startup and shutdown of system services, including daemons, user sessions, and other background processes. It also provides a comprehensive suite of tools for managing system resources, such as network configuration, logging, process control, and other system tasks. Systemd also includes a built-in watchdog mechanism, which can be used to detect and respond to system faults. Systemd is widely used in many Linux distributions and is becoming increasingly popular in other Unix-like operating systems.
eudev
Supervisor
Chaperone Process Manager
There is a long list of technical arguments why OpenRC is better than systemd. System popularity seems to win out these days. But as we have seen over the centuries, popularity has failed us many times. Even Upstart was better, badly enough, it faded away.