partman-crypto does support activating existing volumes on ubuntu.
In d-i interface, one needs to enter manual partitioning, enter encryption sub-menu and select option to activate existing encrypted volumes. At which point all encrypted volumes will be attempted to be activated and user maybe asked for a password (multiple times, if there is more than one encrypted volume). After which one needs to back-out to automatic partitioning & gain options to for example upgrade encrypted volume.
This "loop via activating crypt volumes" can be implemented directly, or we can modify ubiquity's embedded d-i to execute that option for us and do question pop-ups about that.
But there is a caveat, once activated one cannot "deactivate" those volumes. See bug 291494 .
Also "resize" option can be dangerous, as there is no proper resize support for neither LVM2 nor dm-crypt volumes.
The "upgrade" or "reuse" options can be dangerous as well, since I am suspecting that lvm2 and/or ecryptfs user space tools might not be installed. In any case those options should be tested.
partman-crypto does support activating existing volumes on ubuntu.
In d-i interface, one needs to enter manual partitioning, enter encryption sub-menu and select option to activate existing encrypted volumes. At which point all encrypted volumes will be attempted to be activated and user maybe asked for a password (multiple times, if there is more than one encrypted volume). After which one needs to back-out to automatic partitioning & gain options to for example upgrade encrypted volume.
This "loop via activating crypt volumes" can be implemented directly, or we can modify ubiquity's embedded d-i to execute that option for us and do question pop-ups about that.
But there is a caveat, once activated one cannot "deactivate" those volumes. See bug 291494 .
Also "resize" option can be dangerous, as there is no proper resize support for neither LVM2 nor dm-crypt volumes.
The "upgrade" or "reuse" options can be dangerous as well, since I am suspecting that lvm2 and/or ecryptfs user space tools might not be installed. In any case those options should be tested.