dc3b976f33
dracut does not install the kernel module of the block device that contains the root filesystem if the following preconditions are met: - Running in host-only mode. - Symlinks of all block devices needed to boot the system pointing to virtual subsystems. The get_dev_module function uses "udevadm info -a" to get the corresponding kernel modules of a /sys/class/*/* or /dev/* device. This function is called in modules.d/90kernel-modules/module-setup.sh to detect if dracut must install block device drivers in host-only mode. The symlinks in /sys/dev/block/ usually point to "real" devices in /sys/devices/pci*. But, we have come across some NVMe systems where the kernel creates the symlinks in /sys/dev/block/ pointing to "virtual" devices instead. In this case, udevadm never finds any "driver" attributes following up the chain of parent devices. |
||
|---|---|---|
| .github | ||
| docs | ||
| dracut.conf.d | ||
| install.d | ||
| man | ||
| modules.d | ||
| pkgbuild | ||
| shell-completion/bash | ||
| src | ||
| test | ||
| tools | ||
| .astylerc | ||
| .dir-locals.el | ||
| .editorconfig | ||
| .gitignore | ||
| .kateconfig | ||
| .kateproject | ||
| .mailmap | ||
| .packit.yml | ||
| .shellcheckrc | ||
| .vimrc | ||
| AUTHORS | ||
| COPYING | ||
| Makefile | ||
| NEWS.md | ||
| README.md | ||
| configure | ||
| dracut-catimages.sh | ||
| dracut-functions.sh | ||
| dracut-init.sh | ||
| dracut-initramfs-restore.sh | ||
| dracut-logger.sh | ||
| dracut.conf | ||
| dracut.sh | ||
| lsinitrd.sh | ||
README.md
dracut
dracut is an event driven initramfs infrastructure.
dracut (the tool) is used to create an initramfs image by copying tools and files from an installed system and combining it with the dracut framework, usually found in /usr/lib/dracut/modules.d.
Unlike other implementations, dracut hard-codes as little as possible into the initramfs. The initramfs has (basically) one purpose in life -- getting the rootfs mounted so that we can transition to the real rootfs. This is all driven off of device availability. Therefore, instead of scripts hard-coded to do various things, we depend on udev to create device nodes for us and then when we have the rootfs's device node, we mount and carry on. This helps to keep the time required in the initramfs as little as possible so that things like a 5 second boot aren't made impossible as a result of the very existence of an initramfs.
Most of the initramfs generation functionality in dracut is provided by a bunch of generator modules that are sourced by the main dracut script to install specific functionality into the initramfs. They live in the modules.d subdirectory, and use functionality provided by dracut-functions to do their work.
Currently dracut lives on github.com and kernel.org.
The tarballs can be found here: http://www.kernel.org/pub/linux/utils/boot/dracut/ ftp://ftp.kernel.org/pub/linux/utils/boot/dracut/
Git: https://github.com/dracutdevs/dracut.git http://git.kernel.org/?p=boot/dracut/dracut.git
Project Documentation: http://www.kernel.org/pub/linux/utils/boot/dracut/dracut.html
Project Wiki: http://dracut.wiki.kernel.org
See the github issue tracker for things which still need to be done and HACKING.md for some instructions on how to get started. There is also a mailing list that is being used for the discussion -- initramfs@vger.kernel.org. It is a typical vger list, send mail to majordomo@vger.kernel.org with body of 'subscribe initramfs email@host.com'
Licensed under the GPLv2