Using the server install ISO, it's possible to specify root on LUKS and variations thereof - for instance, root on LUKS on MD-RAID, root on LVM on LUKS on MD-RAID, and so forth. The installer does the right thing and initramfs-tools does everything necessary to support booting this sort of thing.
However, systemd gives a 90-second timeout on restart or shutdown, presumably because it cannot dispose of the things beneath root.
It's wholly unclear to me where the 90-second timeout is specified, should I wish to shorten it to reboot without the futile delay, but more to the point, there seems to be infrastructure for handling this kind of situation that doesn't exist in Ubuntu at present.
I was pointed at this:
https://www.freedesktop.org/wiki/Software/systemd/InitrdInterface/
However, Ubuntu seems not to have anything in its initramfs-tools to facilitate "shutdown-initrd" functionality.
I haven't tested this, but I suspect this problem will exist for folks running root on MD-RAID without the LUKS as well. Either way, a relatively common vanilla install will force 90-second timeouts on users, which is unfortunate.
ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: systemd 229-2ubuntu1 [modified: usr/share/dbus-1/system-services/org.freedesktop.systemd1.service]
ProcVersionSignature: Ubuntu 4.4.0-11.26-generic 4.4.4
Uname: Linux 4.4.0-11-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl nvidia_uvm nvidia_modeset nvidia
ApportVersion: 2.20-0ubuntu3
Architecture: amd64
Date: Tue Mar 8 18:06:45 2016
InstallationDate: Installed on 2016-02-24 (13 days ago)
InstallationMedia: Ubuntu-Server 16.04 LTS "Xenial Xerus" - Alpha amd64 (20160219)
Lsusb:
Bus 002 Device 002: ID 1058:0820 Western Digital Technologies, Inc. My Passport Ultra (WDBMWV, WDBZFP)
Bus 002 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 001 Device 003: ID 046d:c408 Logitech, Inc. Marble Mouse (4-button)
Bus 001 Device 002: ID 046d:c318 Logitech, Inc. Illuminated Keyboard
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
MachineType: Gigabyte Technology Co., Ltd. To be filled by O.E.M.
ProcEnviron:
TERM=xterm-color
PATH=(custom, no user)
XDG_RUNTIME_DIR=<set>
LANG=en_US.UTF-8
SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-11-generic.efi.signed root=/dev/mapper/hostname-root ro net.ifnames=0 biosdevname=0
SourcePackage: systemd
SystemdDelta:
[EXTENDED] /lib/systemd/system/systemd-timesyncd.service → /lib/systemd/system/systemd-timesyncd.service.d/disable-with-time-daemon.conf
[EXTENDED] /lib/systemd/system/rc-local.service → /lib/systemd/system/rc-local.service.d/debian.conf
2 overridden configuration files found.
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 12/04/2015
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: F1
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: X150M-PRO ECC-CF
dmi.board.vendor: Gigabyte Technology Co., Ltd.
dmi.board.version: x.x
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvrF1:bd12/04/2015:svnGigabyteTechnologyCo.,Ltd.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnGigabyteTechnologyCo.,Ltd.:rnX150M-PROECC-CF:rvrx.x:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: Gigabyte Technology Co., Ltd.
I just managed to time it right such that I caught the error on my screen, and in doing to noticed a glaring typo that's likely indicative of the overall code quality of the related software.
I'd be grateful for debugging tips. I hope Canonical's not going to ship software that punishes LUKS users with these 90-second delays each reboot or shutdown. I'd settle for having a way to shorten the timeout, but systemd seems hopelessly opaque and I haven't found where this is set as yet.
Anyway, thanks in advance for fixing this annoyance.