dracut (initramfs)

Dracut is a tool to an initramfs for Linux systems - create - a temporary file system. This is used by the Linux kernel during the boot process until the final root file system is mounted.

The aim of dracut is to provide a universal interface for generating an initramfs that can be used by all distributions. Because so far every distribution uses a self-developed flow to generate these initramfs what usability and interoperability lowers and increases the risk of errors.

Technical Details

Dracut is modular and provides defined interfaces to relatively easy to extend the functionality.

All modules must in the scripting language for the Debian Almquist Shell ( / bin / dash ), a compact operating system shell be programmed.

Dracut offers special Dash functions to

• Files easily embed when creating the initramfs.
• Unnecessary programs in the initramfs to install (eg, awk )
• Check for dependencies among the dracut modules.
• To define hooks.

Hooks

As Hooks Dash scripts are referred to that are called or executed when certain events occur. These are ...

• Cmdline - evaluating the boot parameters.
• Pre - udev - before the hardware detection starts.
• Pre - mount - immediately before executing the mount command.
• Mount - if the directories are mounted.
• Pre -pivot - before the initramfs is leaving and will be changed in the final root directory.

History

In the summer of 2009, dracut for the first time with Fedora 12 part of a widespread Linux distribution. Meanwhile, the project is located directly at the Linux kernel project.