Manually mounting whole disk encryted drive
The Debian installer (which I've been using with the Ubuntu Alternate Install CD for years) makes it easy to set up whole disk crypto with cryptsetup, LUKS, and LVM. So easy that it's easy to forget how to get to the info when you're not longer booting the disk, but are accessing it in an external drive. So here's a reminder of how to do it when it's LVM over a LUKS encrypted partition. ls dev or dmesg to get the device name of the encrypted partition. Let's say it was /dev/sdb1.
sudo cryptsetup luksOpen /dev/sdb1 arbitraryname
sudo lvscan
This'll give you the name of the logical volumes as they were originally set up. Let's say the one you're interested in was /dev/myvolumegroup/root.
You're almost there; all you have to do is make a mount point, e.g., /mnt/lvroot and:
sudo mount /dev/myvolumegroup/root /mnt/lvroot
Ta da.
Updated: One may have to load some kernel modules before the luksOpen, e.g.,
modprobe dm_mod
modprobe dm_crypt
modprobe aes
And mark the logical volume and/or volume group active:
lvchange -ay logical_volume_name
vgchange -ay volume_group_name