RuckusRD - a super awesome, yet simple, mkinitrd replacement

Copyright 2012-2024 Michael D Labriola [email protected]

Licensed under the GPLv3. See the file COPYING for details.

This utility is a derivative of fedora's livecd-creator's mayflower script, written by David Zeuthen [email protected], circa Fedora 8 (oh my gosh old).

It's been largely rewritten to be a mkinitrd replacement specifically for embedded systems and removable media, but it's also perfectly usable on normal desktop Linux systems.

Strengths:

1. Layered Squashfs Root Filesystem. When supplied with one or more sqsh_layers containing a root filesystem, an initrd created by RuckusRD will create a read-write virtual device for the rootfs by combining the squashfs image(s) (read-only by nature) with a read-write upper layer. If another block device is used for the upper layer, changes to the system will be persistent. If the upper layer is RAM, the system becomes non-persistent (any changes will go away upon reboot).

   Furthermore, when using RAM for upper layer, the lower sqsh_layers can be loaded entirely into RAM, enabling the user to unmount and remove the boot media.

   You don't HAVE to use sqsh_layers, though. You can use an initrd created by RuckusRD to boot a normal old root filesystem and still benefit from the other bits of awesomeness RuckusRD provides.

   See sqsh_layers.txt for more info.

2. Universal Initramfs. Images created by RuckusRD can be used for multiple machines with different hardware without regenerating initrd. All the kernel modules needed for early boot (e.g., sccsi, filesystems), maintenance shells (e.g., USB HID, keyboard), and networking (e.g., wired/wireless subsystems, protocols, device drivers) are included in the initramfs, along with any modules they in turn require.

   Actually, as of v0.16, ALL kernel modules are included in the initramfs so that everything the kernel was configured to be able to do is fully availabile in the maintenence shell.

   All modules and kernel headers can be injected into the root filesystem once mounted (if the initrd was created w/ -o modinject=1), making simply booting the kernel into a kernel installation mechanism (super handy for VMs or kernel testing).

3. Swiss army knife maintenance shell of doom. Just add maint to the kernel commandline. The maintenence shell provided is a fully functional embedded rootfs with BusyBox, eudev, lvm, mdadm, e2fsprogs, squashfs-tools, the OpenZFS userland tools, syslinux, efibootmgr, wired networking utilities, rsync, ssh, and fsarchiver.

4. Easy microcode loading/updating. Initramfs images created w/ RuckusRD automatically include /boot/ucode.img (subprojects/ucode.img gets generated out of ALL the latest Intel and AMD microcode as a convenience but not installed, or you can generate a machine-specific version with microcodenator).

5. Firmware loading made easy. RuckusRD initramfs images can have an appropriate fw.img (e.g., created with firmwarenator) appended to them, or even better you can use fwdev=DISK on the kernel commandline to specify a device containing fw.sqsh. This makes updating firmware independent of the initrd or kernel upgrade process. A giant fw.sqsh is built in subprojects/fw.sqsh out of ALL the latest firmware, but isn't installed. Alternatively, you can create a machine-specific set of firmware with firmwarenator.

See the manpage for more details, or docs for more developmental ramblings. ;-)

Get the latest and greatest from https://github.com/sourceruckus/ruckusrd and take a gander at the sister utilities firmwarenator and microcodenator at https://github.com/sourceruckus/firmwarenator and https://github.com/sourceruckus/microcodenator.