-This is the simple skeleton of a new initrd infrastructure.
-Information about our goals and aims can be found at
-https://fedoraproject.org/wiki/Initrdrewrite
+dracut
+------
+dracut is an event driven initramfs infrastructure.
-One of the biggest goals is that we're using common pieces from the
-system as much as possible and we also want to do this in a way that
-can eventually get some cross-distro buy-in. But for now, it's a
-playground to see what of our ideas are actually feasible.
+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 existing initramfs's, this is an attempt at having as little as
+possible hard-coded into the initramfs as possible. 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. It's likely that
+we'll grow some hooks for running arbitrary commands in the flow of
+the script, but it's worth trying to resist the urge as much as we can
+as hooks are guaranteed to be the path to slow-down.
-Licensed under the GPLv2
+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.
+
+Some general rules for writing modules:
+ * Use one of the inst family of functions to actually install files
+ on to the initramfs. They handle mangling the pathnames and (for binaries,
+ scripts, and kernel modules) installing dependencies as appropriate so
+ you do not have to.
+ * Scripts that end up on the initramfs should be POSIX compliant. dracut
+ will try to use /bin/dash as /bin/sh for the initramfs if it is available,
+ so you should install it on your system -- dash aims for strict POSIX
+ compliance to the extent possible.
+ * Hooks MUST be POSIX compliant -- they are sourced by the init script,
+ and having a bashism break your user's ability to boot really sucks.
+ * Generator modules should have a two digit numeric prefix -- they run in
+ ascending sort order. Anything in the 90-99 range is stuff that dracut
+ relies on, so try not to break those hooks.
+ * Hooks must have a .sh extension.
+ * Generator modules are described in more detail in README.modules.
+ * We have some breakpoints for debugging your hooks. If you pass 'rdbreak'
+ as a kernel parameter, the initramfs will drop to a shell just before
+ switching to a new root. You can pass 'rdbreak=hookpoint', and the initramfs
+ will break just before hooks in that hookpoint run.
+
+Also, there is an attempt to keep things as distribution-agnostic as
+possible. Every distribution has their own tool here and it's not
+something which is really interesting to have separate across them.
+So contributions to help decrease the distro-dependencies are welcome.
+
+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:
+ git://git.kernel.org/pub/scm/boot/dracut/dracut.git
+ http://git.kernel.org/pub/scm/boot/dracut/dracut.git
+ https://git.kernel.org/pub/scm/boot/dracut/dracut.git
+
+ git@github.com:dracutdevs/dracut.git
-Copyright 2008, Red Hat, Inc. -- Jeremy Katz <katzj@redhat.com>
+Git Web:
+ 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 TODO file for things which still need to be done and HACKING 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
projects / thirdparty / dracut.git / blobdiff