apt-cacher over NFS directory exits with success and no logs

[Avio]

I was trying to move my apt-cacher directory from /var/cache to a NFS mounted directory with plenty of space. Unfortunately, apt-cacher doesn't like NFS too much, and continues to exit with exit code 0 without giving an explanation about this.

I've managed to change the cache directory to many locations on my system, but only on locally mounted fs (as you can see below).

Sat Jan 23 15:48:03 2016|debug [25742]: Apt-Cacher version 1.7.10 started with Debug output enabled
Sat Jan 23 15:48:03 2016|debug [25741]: Clean up before exiting.
Sat Jan 23 15:49:11 2016|debug [25742]: received SIGTERM, terminating
Sat Jan 23 15:49:11 2016|debug [25742]: Clean up before exiting.
Sat Jan 23 15:49:11 2016|debug [25742]: Killing entire process group
Sat Jan 23 15:50:01 2016|warn [25911]: Info: /var/cache/apt-cacher/private missing. Doing mkdir -p /var/cache/apt-cacher/private
Sat Jan 23 15:50:01 2016|warn [25911]: Info: /var/cache/apt-cacher/import missing. Doing mkdir -p /var/cache/apt-cacher/import
Sat Jan 23 15:50:01 2016|warn [25911]: Info: /var/cache/apt-cacher/packages missing. Doing mkdir -p /var/cache/apt-cacher/packages
Sat Jan 23 15:50:01 2016|warn [25911]: Info: /var/cache/apt-cacher/headers missing. Doing mkdir -p /var/cache/apt-cacher/headers
Sat Jan 23 15:50:01 2016|debug [25911]: Using IPv6
Sat Jan 23 15:50:01 2016|debug [25911]: Listening on :::3142
Sat Jan 23 15:50:01 2016|debug [25911]: fork listener
Sat Jan 23 15:50:01 2016|info [25911]: Forked listener 25913
Sat Jan 23 15:50:01 2016|debug [25913]: Apt-Cacher version 1.7.10 started with Debug output enabled
Sat Jan 23 15:50:01 2016|debug [25911]: Clean up before exiting.
Sat Jan 23 15:50:31 2016|debug [25913]: received SIGTERM, terminating
Sat Jan 23 15:50:31 2016|debug [25913]: Clean up before exiting.
Sat Jan 23 15:50:31 2016|debug [25913]: Killing entire process group
Sat Jan 23 15:52:17 2016|warn [26114]: Info: /tmp/apt-cacher/private missing. Doing mkdir -p /tmp/apt-cacher/private
Sat Jan 23 15:52:17 2016|warn [26114]: Info: /tmp/apt-cacher/import missing. Doing mkdir -p /tmp/apt-cacher/import
Sat Jan 23 15:52:17 2016|warn [26114]: Info: /tmp/apt-cacher/packages missing. Doing mkdir -p /tmp/apt-cacher/packages
Sat Jan 23 15:52:17 2016|warn [26114]: Info: /tmp/apt-cacher/headers missing. Doing mkdir -p /tmp/apt-cacher/headers
Sat Jan 23 15:52:17 2016|debug [26114]: Using IPv6
Sat Jan 23 15:52:17 2016|debug [26114]: Listening on :::3142
Sat Jan 23 15:52:17 2016|debug [26114]: fork listener
Sat Jan 23 15:52:17 2016|info [26114]: Forked listener 26115
Sat Jan 23 15:52:17 2016|debug [26115]: Apt-Cacher version 1.7.10 started with Debug output enabled
Sat Jan 23 15:52:17 2016|debug [26114]: Clean up before exiting.
Sat Jan 23 15:53:13 2016|debug [26115]: received SIGTERM, terminating
Sat Jan 23 15:53:13 2016|debug [26115]: Clean up before exiting.
Sat Jan 23 15:53:13 2016|debug [26115]: Killing entire process group
Sat Jan 23 15:54:04 2016|warn [26239]: Info: /mnt/boh/apt-cacher/private missing. Doing mkdir -p /mnt/boh/apt-cacher/private
Sat Jan 23 15:54:04 2016|warn [26239]: Info: /mnt/boh/apt-cacher/import missing. Doing mkdir -p /mnt/boh/apt-cacher/import
Sat Jan 23 15:54:04 2016|warn [26239]: Info: /mnt/boh/apt-cacher/packages missing. Doing mkdir -p /mnt/boh/apt-cacher/packages
Sat Jan 23 15:54:04 2016|warn [26239]: Info: /mnt/boh/apt-cacher/headers missing. Doing mkdir -p /mnt/boh/apt-cacher/headers
Sat Jan 23 15:54:04 2016|debug [26239]: Using IPv6
Sat Jan 23 15:54:04 2016|debug [26239]: Listening on :::3142
Sat Jan 23 15:54:04 2016|debug [26239]: fork listener
Sat Jan 23 15:54:04 2016|info [26239]: Forked listener 26240
Sat Jan 23 15:54:04 2016|debug [26240]: Apt-Cacher version 1.7.10 started with Debug output enabled
Sat Jan 23 15:54:04 2016|debug [26239]: Clean up before exiting.
Sat Jan 23 15:54:22 2016|debug [26240]: received SIGTERM, terminating
Sat Jan 23 15:54:22 2016|debug [26240]: Clean up before exiting.
Sat Jan 23 15:54:22 2016|debug [26240]: Killing entire process group

But as soon as I set the cache directory to the NFS mount, this the only bit of debugging I can see:

#> sudo service apt-cacher status
● apt-cacher.service - LSB: apt-cacher package caching proxy daemon
   Loaded: loaded (/etc/init.d/apt-cacher)
   Active: active (exited) since Sat 2016-01-23 15:57:35 CET; 23s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 26472 ExecStop=/etc/init.d/apt-cacher stop (code=exited, status=0/SUCCESS)
  Process: 26508 ExecStart=/etc/init.d/apt-cacher start (code=exited, status=0/SUCCESS)

Jan 23 15:57:35 goomba systemd[1]: Starting LSB: apt-cacher package caching proxy daemon...
Jan 23 15:57:35 goomba apt-cacher[26508]: Starting Apt-Cacher: apt-cacher.
Jan 23 15:57:35 goomba systemd[1]: Started LSB: apt-cacher package caching proxy daemon.

and no logfile at all is produced. This is very weird.

File and directory permissions are right, I've changed user from www-data to my main user a couple of times with no problems. apt-cacher was also smart enough to detect wrong permissions on its cache directory and change some (not all) of them to its current user.

I'm using apt-cacher 1.7.10 under Ubuntu Vivid.

Last weird thing: apt-cacher --version never outputs the version, both with or without sudo, both when the service is correctly configured and running or not (yes, I've purged it and reinstalled). Never. Weird.