Comment 13 for bug 2058511

I was able to work around the UI not showing LUKS volumes with using the autoinstall.yaml configs,
https://github.com/asayler/ubuntu_autoinstall/blob/master/user-data-encrypted; with everything but the storage section stripped out. This however will format and clear out the entire drive so its not usable for prexisting partitions with data on them.

Playing around with the yaml files more lead to this https://pastebin.com/2HGrWMYF, in a UEFI setup the auto install requires a grub partition and disk fully defined. For the rest of the data partition like / and /boot we can use a prexisting "type: device" (https://curtin.readthedocs.io/en/latest/topics/storage.html) to provide the block device, and using the "preserve: true" should keep the onboard data intact. Only issue with this is that the newly install os does not have cryptsetup in the initramfs so it needs to be manually installed before rebooting.