Init vs SystemD Linux | DevOps | Interview | Tech Arkit
What is the difference between Init (SysVinit) and SystemD in Linux. #init #systemd #sysvinit #server #linuxserver #linuxadministrator #techarkit
Boot Process: When the computer boots up, the system BIOS or UEFI firmware hands control over to the bootloader (such as GRUB). The bootloader then loads the Linux kernel into memory and passes control to it.
Kernel Initialization: The Linux kernel initializes hardware, mounts the root filesystem, and starts the init process.
init Process: The init process is the first process started by the kernel and has process ID 1. It's responsible for initializing the system and managing system services.
Runlevels: SysVinit organizes the system startup and shutdown process into runlevels. A runlevel defines a state of the system, indicating which services should be started or stopped. Common runlevels include single-user mode, multi-user mode, and graphical mode. Each runlevel has associated initialization scripts that start or stop services.
Initialization Scripts: The initialization scripts, located in directories like /etc/init.d, are shell scripts responsible for starting, stopping, and managing individual services. These scripts are executed sequentially during system startup and shutdown, following the instructions defined for each runlevel.
Dependency Handling: SysVinit relies on a simple dependency system, where services are started in a predefined order based on their dependencies. However, managing complex interdependencies between services can be challenging with SysVinit.
Manual Service Management: In SysVinit, administrators often manually manage services using commands like service or chkconfig, which interact with the initialization scripts to start, stop, enable, or disable services.
