documentation remote unlocking inaccurate

[Muelli]

The documentation in /usr/share/doc/cryptsetup/README.remote.gz write smth along these lines:

To unlock from remote, you could do something like this:

ssh -o "UserKnownHostsFile=~/.ssh/known_hosts.initramfs" \
    -i "~/id_rsa.initramfs" <email address hidden> \
    "echo -ne \"secret\" >/lib/cryptsetup/passfifo"

However, due to plymouth being installed by default (maybe bug 595648) it doesn't respect the fifo we're supposed to be writing to.

Uninstalling plymouth doesn't work:

root@ubuntu:~# apt-get purge plymouth
Reading package lists... Done
Building dependency tree
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help to resolve the situation:

The following packages have unmet dependencies:
 cron : Depends: upstart-job
E: Error, pkgProblemResolver::Resolve generated breaks, this may be caused by held packages.
root@ubuntu:~#

Installing the plymouth-disabler also doesn't help.

What helps is to kill the plymouthd process before writing to the fifo. However, I can't figure out how to reliably determine the PID of plymouthd.

I expected the documentation to be reasonably accurate.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: cryptsetup 2:1.6.1-1ubuntu7
ProcVersionSignature: Ubuntu 3.19.0-12.12-generic 3.19.3
Uname: Linux 3.19.0-12-generic x86_64
ApportVersion: 2.17-0ubuntu1
Architecture: amd64
CurrentDesktop: GNOME
Date: Thu Apr 9 08:02:27 2015
SourcePackage: cryptsetup
UpgradeStatus: No upgrade log present (probably fresh install)
crypttab:
 # target source key options
 chinacrypto UUID=286618e1-09c0-4f5c-9bb9-1cf5f96b2dc6 none luks,retry=1,lvm=chinalvm