Hi.

When using the ifupdown-plugin in managed mode, then ifupdown (itself) doesn't work well anymore.

An example, NM is on, ifupdown-plugin in managed mode:
root@host:~# ifconfig
eth0      Link encap:Ethernet  HWaddr 50:26:90:aa:64:1f
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B)  TX bytes:0 (0.0 B)
          Interrupt:17 Memory:f2d00000-f2d20000

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16436  Metric:1
          RX packets:154 errors:0 dropped:0 overruns:0 frame:0
          TX packets:154 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:11976 (11.6 KiB)  TX bytes:11976 (11.6 KiB)

wlan0     Link encap:Ethernet  HWaddr 60:67:20:09:9a:a4
          UP BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:233 errors:0 dropped:0 overruns:0 frame:0
          TX packets:208 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:160277 (156.5 KiB)  TX bytes:47115 (46.0 KiB)


wlan0 is obviously brought up, as NM needs it for scanning...

Now when I try to manually use ifupdown (i.e. ifup or ifdown):
root@host:~# ifup wlan0
wpa_supplicant: /sbin/wpa_supplicant daemon failed to start
run-parts: /etc/network/if-pre-up.d/wpasupplicant exited with return code 1
Internet Systems Consortium DHCP Client 4.2.4
Copyright 2004-2012 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/

[  542.869174] iwlwifi 0000:0a:00.0: L1 Enabled; Disabling L0S
[  542.878424] iwlwifi 0000:0a:00.0: Radio type=0x1-0x2-0x0
[  543.019028] ADDRCONF(NETDEV_UP): wlan0: link is not ready
Listening on LPF/wlan0/60:67:20:09:9a:a4
Sending on   LPF/wlan0/60:67:20:09:9a:a4
Sending on   Socket/fallback
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 3
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 8
DHCPDISCOVER on wlan0 to 255.255.255.255 port 67 interval 12

It doesn't work; in this example, because wpa_supplicant fails to start (I guess because it runs already).


It would be awesome if ifupdown (itself) would work even while NM is running (in managed mode).

I guess this should be possible, by utilising the hooks provided by ifupdown:

So such a hook script could first detect if the interface for which ifupdown (itself) was called, is managed _now_ by NM.
If so it gives the parameters to NM and that does the work or (if that is not possible) NM is "simply" told to enable/disable the desired connection (that it anyway manages via the ifupdown-plugin).


If that should really not be possible,... then, as a inferior fallback, hooks to ifupdown (itself) should be provided, that, when the desired interface is managed _now_ by NM, ifupdown (itself) bails out with an error and description, that this interface is currently managed by NM and cannot be managed by ifupdown.



Cheers,
Chris.