upgrading lubuntu groovy -> impish by reinstalling on existing LUKS partition fails

[SideShowFry]

The existing partition with LUKS / ext4 was created by installer during installation of groovy from lubuntu live usb.

Last night, I attempted to upgrade by reinstalling to same partition, hoping to preserve & update /home. /boot/efi is on a separate device, not encrypted. /boot is not a separate mount, it's in the encrypted /. All partitions were left as "keep", not format. I used a live usb created from lubuntu-21.10-desktop-amd64.iso downloaded yesterday via magnet link.

Without first decrypting the LUKS partition, the manual partitioning step showed the partition as LUKS. Attempting to use this failed quickly during installation with an error message along the lines of "unable to unpack squashfs" (sorry, I wasn't taking notes here).

With the partition already decrypted, the manual partitioning step shows the partition as ext4. Installation fails during LuksBootKeyFileJob, with this in stdout:

21:35:21 [6]: virtual void Calamares::JobThread::run()
    Starting job "Configuring LUKS key file." ( 14 / 36 )
21:35:21 [6]: virtual Calamares::JobResult LuksBootKeyFileJob::exec()
    There are 1 LUKS partitions
    .. root "/dev/nvme1n1p1" passphrase? false
    .. No root passphrase.

...

    ERROR: Installation failed: "Encrypted rootfs setup error"
    .. - message: "Encrypted rootfs setup error"
    .. - details: Root partition /dev/nvme1n1p1 is LUKS but no passphrase has been set.

Either way, the installer never asked for the passphrase. /crypto_keyfile.bin already existed from groovy installation, I think. The modified date confirms this. Perhaps calamares could be made to skip LuksBootKeyFileJob in this case.

I was left with a partially installed impish, I think, without things like users or hostname.

I was able to restore the LUKS partition with groovy from a backup image and upgrade to hirsute using the upgrade tool from https://changelogs.ubuntu.com/meta-release, and then to impish using do-release-upgrade.

ProblemType: Bug
DistroRelease: Ubuntu 21.10
Package: calamares (not installed)
ProcVersionSignature: Ubuntu 5.13.0-28.31-generic 5.13.19
Uname: Linux 5.13.0-28-generic x86_64
ApportVersion: 2.20.11-0ubuntu71
Architecture: amd64
CasperMD5CheckResult: unknown
CurrentDesktop: LXQt
Date: Tue Feb 1 13:28:45 2022
InstallationDate: Installed on 2020-12-28 (400 days ago)
InstallationMedia: Lubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
SourcePackage: calamares
UpgradeStatus: Upgraded to impish on 2022-02-01 (0 days ago)

[SideShowFry (fry-n)]

I considered, but did not attempt, these work-arounds:

1) Remove LuksBootKeyFileJob from calamares settings
2) temporarily move /boot to an unencrypted partition so that LuksBootKeyFileJob would not proceed
3) temporarily move /home to another partition and let calamares reformat the LUKS partition

[Simon Quigley (tsimonq2)]

We no longer support either of these releases, sorry for taking so long to follow up.