installing on existing luks/btrfs doesn't ask for passphrase at boot

[fugounashi]

Ubuntu 14.04.3 LTS

after manual cryptsetup luksOpen (as per 1066480) I selected the existing btrfs as root (having renamed the existing root and home subvolumes)

installation proceeds and installs to new root and home subvolumes however the system is not correctly configured to boot:

  no dm-crypt module or cryptsetup in initramfs

  no prompt for passphrase at boot

thanks!

[fugounashi (fugounashi+launchpad)]

it also left the following in the btrfs root:

ubiquity-apt-clone/
ubiquity-apt-clone/apt-clone-state-ubuntu.tar.gz
var/
var/lib

[fugounashi (fugounashi+launchpad)]

the bug is also present in Ubuntu 15.04

the cause is that no crypttab is created

a workaround is as follows (using encrypted volume with existing btrfs on sda4 and boot on sda3 as an example):

(boot install disc, try Ubuntu without installing, and open the encrypted volume as required by https://bugs.launchpad.net/bugs/1066480 https://wiki.ubuntu.com/TrustyTahr/ReleaseNotes/#Boot.2C_installation_and_post-install)
# cryptsetup luksOpen /dev/sda4 sda4_crypt
(perform the installation)
# mount /dev/mapper/sda4_crypt /mnt
# cd /mnt
(clean up leakage)
# rm ubiquity-apt-clone/apt-clone-state-ubuntu.tar.gz
# rmdir ubiquity-apt-clone/ var/lib/ var/
(find the uuid)
# blkid /dev/sda4
(create missing crypttab using uuid)
# echo "sda4_crypt UUID=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx none luks" > /mnt/@/etc/crypttab
(update initrd and grub)
# cd @
# mount /dev/sda3 boot
# for d in dev sys proc; do mount --bind /$d $d; done
# chroot /mnt/@
# update-initramfs -k all -c
# shutdown -r now

[fugounashi (fugounashi+launchpad)]

corrections to last comment: grub doesn't need updating and there should be an exit before shutdown

[fugounashi (fugounashi+launchpad)]

may be the same bug as this: https://bugs.launchpad.net/ubuntu/+source/ubiquity/+bug/1168115

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.