How to ADD one module to initrd using mkinitrd

Question

I've cloned a Linux (Fedora) server system from an IDE drive to a SATA drive but it doesn't boot, failing at switch root. I've done a clean install on the target drive and have learned thru inspection of the initrd files that when installing fedora on a SATA drive it includes the ahci module, which was not used when I had no SATA drives during the installation of my working system.

So I'd like to run mkinitrd to build the new initrd, same as the old but adding the ahci module (probably as a preload)

I'm doing too much guessing, so I wanted to park this question here: Whats the easiest way to build a new initrd from the existing one, just adding a single module?

Here is the diff of the two init files

 diff /media/disk/SATA_initrd/initrd/init /media/disk/PATA_initrd/initrd/init 
50a51,52
> echo "Loading crc-t10dif module"
> modprobe -q crc-t10dif
57,60d58
< echo "Loading ahci module"
< modprobe -q ahci
< echo Waiting for driver initialization.
< stabilized --hash --interval 250 /proc/scsi/scsi
66a65,68
> echo "Loading pata_amd module"
> modprobe -q pata_amd
> echo Waiting for driver initialization.
> stabilized --hash --interval 250 /proc/scsi/scsi

and the init file from the initrd that I want to modify.

#!/bin/nash

mount -t proc /proc /proc
setquiet
echo Mounting proc filesystem
echo Mounting sysfs filesystem
mount -t sysfs /sys /sys
echo Creating /dev
mount -o mode=0755 -t tmpfs /dev /dev
mkdir /dev/pts
mount -t devpts -o gid=5,mode=620 /dev/pts /dev/pts
mkdir /dev/shm
mkdir /dev/mapper
echo Creating initial device nodes
mknod /dev/null c 1 3
mknod /dev/zero c 1 5
mknod /dev/systty c 4 0
mknod /dev/tty c 5 0
mknod /dev/console c 5 1
mknod /dev/ptmx c 5 2
mknod /dev/tty0 c 4 0
mknod /dev/tty1 c 4 1
mknod /dev/tty2 c 4 2
mknod /dev/tty3 c 4 3
mknod /dev/tty4 c 4 4
mknod /dev/tty5 c 4 5
mknod /dev/tty6 c 4 6
mknod /dev/tty7 c 4 7
mknod /dev/tty8 c 4 8
mknod /dev/tty9 c 4 9
mknod /dev/tty10 c 4 10
mknod /dev/tty11 c 4 11
mknod /dev/tty12 c 4 12
mknod /dev/ttyS0 c 4 64
mknod /dev/ttyS1 c 4 65
mknod /dev/ttyS2 c 4 66
mknod /dev/ttyS3 c 4 67
echo Setting up hotplug.
hotplug
echo Creating block device nodes.
mkblkdevs
echo "Loading ehci-hcd module"
modprobe -q ehci-hcd
echo "Loading ohci-hcd module"
modprobe -q ohci-hcd
echo "Loading uhci-hcd module"
modprobe -q uhci-hcd
mount -t usbfs /proc/bus/usb /proc/bus/usb
echo "Loading ext3 module"
modprobe -q ext3
echo "Loading crc-t10dif module"
modprobe -q crc-t10dif
echo "Loading scsi_mod module"
modprobe -q scsi_mod
echo "Loading sd_mod module"
modprobe -q sd_mod
echo "Loading libata module"
modprobe -q libata
echo "Loading ata_generic module"
modprobe -q ata_generic
echo "Loading pata_acpi module"
modprobe -q pata_acpi
echo Waiting for driver initialization.
stabilized --hash --interval 250 /proc/scsi/scsi
echo "Loading pata_amd module"
modprobe -q pata_amd
echo Waiting for driver initialization.
stabilized --hash --interval 250 /proc/scsi/scsi
echo "Loading dm-mod module"
modprobe -q dm-mod
echo "Loading dm-mirror module"
modprobe -q dm-mirror
echo "Loading dm-zero module"
modprobe -q dm-zero
echo "Loading dm-snapshot module"
modprobe -q dm-snapshot
echo Making device-mapper control node
mkdmnod
modprobe scsi_wait_scan
rmmod scsi_wait_scan
mkblkdevs
echo Scanning logical volumes
lvm vgscan --ignorelockingfailure
echo Activating logical volumes
lvm vgchange -ay --ignorelockingfailure  VolGroup00
resume /dev/VolGroup00/LogVol01
echo Creating root device.
mkrootdev -t ext3 -o defaults,ro /dev/VolGroup00/LogVol00
echo Mounting root filesystem.
mount /sysroot
echo Setting up other filesystems.
setuproot
loadpolicy
echo Switching to new root and running init.
switchroot
echo Booting has failed.
sleep -1

Answer 1

You do not need to worry about all the already installed modules. To begin with, boot into the rescue disk.

chroot /mnt/sysimage      # this is for Fedora specifically - YMMV
cp /boot/initrd-2.26.27.24-78.2.53-fc9.x86_64.img \
     /boot/initrd-2.26.27.24-78.2.53-fc9.x86_64.old
mkinitrd --preload ahci -f /boot/initrd-2.26.27.24-78.2.53-fc9.x86_64.img \
     2.26.27.24-78.2.53-fc9.x86_64

exit and reboot the system. 

slick

You don't have to worry about all the modprobes before the "driver initialization"

ignore  --> use the --preload *MODNAME* in the arguments to mkinitrd
ignore  --> for all the rest use --with

JUST add a --preload ahci

helpful links:

• http://www.mail-archive.com/fedora-package-announce@redhat.com/msg21104.html
• http://www.justlinux.com/forum/showthread.php?p=886204

Answer 2

On a Debian system, you edit /etc/initramfs-tools/modules, and put one module name per line into the file. Then you run "mkinitramfs" and voila, it's done.

For Fedora, just put the module name in /etc/modprobe.conf and run mkinitrd. See also https://fedoraproject.org/wiki/KernelCommonProblems.

Answer 3

You need to create a new image and copy the contents of your "old" initrd over to the new and add your module:

dd if=/dev/zero of=~/file-inird count=2500 bs=1024 (or bigger if needed)
losetup /dev/loop0 ~/file-inird
mke2fs /dev/loop0
mkdir ~/mnt
mount /dev/loop0 ~/mnt
cp -a old_mounted_initrd/* ~/mnt/

[.. add your changes ..]

umount ~/mnt
losetup -d /dev/loop0
gzip -c ~/file-inird > initrd-<kernel-version>

I also found this :)

Voilà

Answer 4

Don't you just add the module to /etc/modprobe.conf then run mkinitrd?