root@odroid64:~# systemctl status networking.service
● networking.service - Raise network interfaces
   Loaded: loaded (/lib/systemd/system/networking.service; enabled; vendor preset: enabled)
  Drop-In: /run/systemd/generator/networking.service.d
           └─50-insserv.conf-$network.conf
   Active: failed (Result: exit-code) since Sun 2017-02-19 00:46:35 UTC; 31s ago
     Docs: man:interfaces(5)
  Process: 3597 ExecStop=/sbin/ifdown -a --read-environment (code=exited, status=0/SUCCESS)
  Process: 3967 ExecStart=/sbin/ifup -a --read-environment (code=exited, status=1/FAILURE)
  Process: 3963 ExecStartPre=/bin/sh -c [ "$CONFIGURE_INTERFACES" != "no" ] && [ -n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle (code=exited, status=0/SUCCE
 Main PID: 3967 (code=exited, status=1/FAILURE)

Feb 19 00:46:35 odroid64 systemd[1]: Starting Raise network interfaces...
Feb 19 00:46:35 odroid64 wpa_supplicant[3982]: Successfully initialized wpa_supplicant
Feb 19 00:46:35 odroid64 wpa_supplicant[3982]: wlan0: Unsupported driver 'rtl8812au'
Feb 19 00:46:35 odroid64 ifup[3967]: /etc/network/if-pre-up.d/wpasupplicant: 120: /etc/network/if-pre-up.d/wpasupplicant: cannot create /dev/stderr: No such device or address
Feb 19 00:46:35 odroid64 ifup[3967]: run-parts: /etc/network/if-pre-up.d/wpasupplicant exited with return code 1
Feb 19 00:46:35 odroid64 ifup[3967]: Failed to bring up wlan0.
Feb 19 00:46:35 odroid64 systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Feb 19 00:46:35 odroid64 systemd[1]: Failed to start Raise network interfaces.
Feb 19 00:46:35 odroid64 systemd[1]: networking.service: Unit entered failed state.
Feb 19 00:46:35 odroid64 systemd[1]: networking.service: Failed with result 'exit-code'.