In the last debian releases /etc/nologin is just a symlink to
/var/lib/initscripts/nologin, so it should exist for regular behaviour
of the nologin feature. IMHO, a better default is to include it in the
repository so to recreate it if needed.

Thanks,
Gian Piero.

Gian Piero Carrubba wrote:

The state of /etc/nologin is sorta confusing:

* nologin(5) still claims that /etc/nologin is the flag file whose existance
  controls nologin, not mentioning that it´s a symlink to a file that may
  not exist. rcS(5) does mention that, but it's not the place many
  people will look.

* /etc/init.d/rmnologin still has comments indicating it removes
  /etc/nologin, even though it doesn't, instead removing the file in
  /var.

* Of all the systems running sid I surveyed, none currently had a
  /etc/nologin file or symlink. This includes one that was cleanly installed
  less than a month ago.

* initscript's postinst creates the /etc/nologin symlink on initial
  install, and on upgrade.

* shutdown unlinks /etc/nologin. The easiest way to see this happen
  is to run shutdown -k now. In other circumstances, it will open
  /etc/nologin for write. This can remove the symlink and replace it
  with the file.

* As a test I reinstalled initscripts, letting it recreate the symlink.
  Then I rebooted. /etc/nologin was gone again. I'n not 100% sure what
  does the deed, but I suspect it's shutdown(8).

So, from the POV of etckeeper, if it tracks /etc/nologin in revision
control, the file will be constantly removed, deleted, change from a
symlink to a regular file, etc. Lots of noise. Also, etckeeper doesn't
really guarantee it preserves every file in /etc that the system needs
for operation. Other noisy yet possibly essential gunk like
/etc/blkid.tab, /etc/ld.so.cache, etc is also ignored. If /etc/nologin
were a stable symlink as (parts of) the system seem to intend it to be,
I'd agree with you, Gian.

From the POV of Debian system coherency and comprehensability,
/etc/nologin seems to be a mess that someone should perhaps finish
cleaning up?