$ cat /etc/network/interfaces.d/loopback.conf
auto lo
iface lo inet loopback
$ cat /etc/network/interfaces.d/primary.conf
auto eth0
iface eth0 inet dhcp
iface eth0 inet6 auto
$ nmcli dev
DEVICE TYPE STATE
eth0 802-3-ethernet unmanaged
eth1 802-3-ethernet connected
$ grep NetworkManager /var/log/syslog
...
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: parsing file /etc/network/interfaces
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: source line includes interfaces file(s) /etc/network/interfaces.d/*
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: parsing file /etc/network/interfaces.d/loopback.conf
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: finished parsing file /etc/network/interfaces.d/loopback.conf
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: parsing file /etc/network/interfaces.d/primary.conf
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: finished parsing file /etc/network/interfaces.d/primary.conf
Jan 27 09:15:48 test NetworkManager[1091]: interface-parser: finished parsing file /etc/network/interfaces
...
Works like a charm. Thanks for integrating the patch.
Manual test: RELEASE= 14.04 CODENAME= trusty DESCRIPTION= "Ubuntu Trusty Tahr (development branch)"
$ cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_
DISTRIB_
DISTRIB_
$ cat /etc/network/ interfaces interfaces. d/*
source /etc/network/
$ cat /etc/network/ interfaces. d/loopback. conf
auto lo
iface lo inet loopback
$ cat /etc/network/ interfaces. d/primary. conf
auto eth0
iface eth0 inet dhcp
iface eth0 inet6 auto
$ nmcli dev
DEVICE TYPE STATE
eth0 802-3-ethernet unmanaged
eth1 802-3-ethernet connected
$ grep NetworkManager /var/log/syslog 1091]: interface-parser: parsing file /etc/network/ interfaces 1091]: interface-parser: source line includes interfaces file(s) /etc/network/ interfaces. d/* 1091]: interface-parser: parsing file /etc/network/ interfaces. d/loopback. conf 1091]: interface-parser: finished parsing file /etc/network/ interfaces. d/loopback. conf 1091]: interface-parser: parsing file /etc/network/ interfaces. d/primary. conf 1091]: interface-parser: finished parsing file /etc/network/ interfaces. d/primary. conf 1091]: interface-parser: finished parsing file /etc/network/ interfaces
...
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
Jan 27 09:15:48 test NetworkManager[
...