OK, I've finally found the problem(s). Was a bunch of little nasty problems, that's why it was difficult to debug.
1) The 15.10 beta installer had filled /etc/initramfs-tools/conf.d/resume with RESUME=UUID=a18e9ec9-1255-4dda-8298-8e10bdbe6835 which is never updated after first installation. Since I had to repair the swap device several times, this was not correct anymore, and furthermore /usr/share/initramfs-tools/hooks/cryptroot can't deal with it. It's important that RESUME=sda2_crypt is entered. 2) That's why /usr/share/initramfs-tools/hooks/cryptroot did not mention the device in /conf/conf.d/cryptroot of the initramfs. Once it is correctly mentioned in this file (after fixing bug 1), the password is fetched and the device is opened at the initramfs phase, i.e. before systemd takes control. This works well. 3) If sda2_crypt is not mentioned in the initramfs' /conf/conf.d/cryptroot, it is not opened while initramfs has control. But then, once systemd takes control, systemd tries to open it since it is listed in /etc/crypttab. But this does not work, since both systemd and plymouthd have bugs. plymouthd can go into an endlesss loop or completey fail, depending whether you have splash/graphical boot or textual. Once bug 1 and 2 are solved, this issue does not occur anymore. 4) But then, system hangs while booting for another reason. systemd still tries to create a swap device and hangs forever. I could not reliably figure out why, but it looks as if it waits for systemd-cryptsetup for to do some things which it doesn't do since the crypt device is already open. Solution: remove the swap option in /etc/crypttab 5) Finally seems to work. Just for the notes: systemd (and plymouth) is so buggy and intransparent that it is far from beeing production-ready. That cost me several evenings of work and headache. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1506139 Title: 15.10beta crashes encrypted swap partition Status in systemd package in Ubuntu: Incomplete Bug description: Hi, I'm usually using a setup with three partitions on a disk Partition 1: plain ext4 boot partition mounted on /boot Partition 2: luks-encrypted swap Partition 3: luks-encrypted btrfs for / /home ... both mentioned in /etc/crypttab like sda2_crypt UUID=a7976d5c-6191-436d-9cf9-2cedf17d0893 none luks,swap,discard sda3_crypt UUID=339b9a90-8292-422d-a3cf-eeb0317e9f84 none luks,discard With several machines I have installed 15.10 beta on and in several cases I experienced the problem that the swap is not activated at boot time and that /dev/disks/by-uuid does not contain a link to the swap partition, and the previously created luks-encrypted swap is destroyed after boot: It is not a luks partition anymore and filled with random (presumably encrypted) bytes without structure. I first thought that this is a problem of the setup process, and repaired the swap manually. But then I found the partition destroyed again. This happend several times on several machines. I am not sure yet what exactly would destroy the partition. ProblemType: Bug DistroRelease: Ubuntu 15.10 Package: cryptsetup 2:1.6.6-5ubuntu2 ProcVersionSignature: Ubuntu 4.2.0-16.19-generic 4.2.3 Uname: Linux 4.2.0-16-generic x86_64 ApportVersion: 2.19.1-0ubuntu2 Architecture: amd64 CurrentDesktop: XFCE Date: Wed Oct 14 18:12:58 2015 InstallationDate: Installed on 2015-10-08 (5 days ago) InstallationMedia: Xubuntu 15.10 "Wily Werewolf" - Alpha amd64 (20150924) SourcePackage: cryptsetup UpgradeStatus: No upgrade log present (probably fresh install) crypttab: sda2_crypt UUID=a7976d5c-6191-436d-9cf9-2cedf17d0893 none luks,swap,discard sda3_crypt UUID=339b9a90-8292-422d-a3cf-eeb0317e9f84 none luks,discard To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1506139/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp