Not today...

Following this article I have LVM on top of Luks for my system. When I boot I encounter the following message:

  Volume group "vg_ssd" not found
  Skipping volume group vg_ssd
Unable to find LVM volume vg_ssd/lv_root

It appears that LVM is started before I open the crypted partition and display this error. To fix this we will manipulate the initramfs \o/.

The issue is in the file /usr/share/initramfs-tools/scripts/local-top/cryptroot

which starts like this:

#!/bin/sh

PREREQ="cryptroot-prepare"

#
# Standard initramfs preamble
#
prereqs()
{
	# Make sure that cryptroot is run last in local-top
	for req in $(dirname $0)/*; do
		script=${req##*/}
		if [ $script != cryptroot ]; then
			echo $script
		fi
	done
}

case $1 in
prereqs)
	prereqs
	exit 0
	;;
esac

# source for log_*_msg() functions, see LP: #272301
. /scripts/functions

Line 10 to 16 it says that cryptroot is run last, in the same directory there is a lvm2 script. So, what is happening is that cryptroot is launched after lvm2 which is not what we want. To fix this remove lines 10 to 16 and replace them with echo "$PREREQ"

#!/bin/sh

PREREQ="cryptroot-prepare"

#
# Standard initramfs preamble
#
prereqs()
{
	echo "$PREREQ"
}

case $1 in
prereqs)
	prereqs
	exit 0
	;;
esac

# source for log_*_msg() functions, see LP: #272301
. /scripts/functions

At the init step files are taken in alphabetical order so cryptroot will come before lvm2 (c < l).

Now we just regenerate the initrd files: update-initramfs -u -k all reboot and voila, it works :D