Help setting up wpa_supplicant

Question

I've been struggling to setup wireless on my headless server: Ubuntu 16.04.2 LTS.

$ sudo wpa_supplicant -Dnl80211 -iwlp3s0 -c/etc/wpa_supplicant/wpa_supplicant.conf
Successfully initialized wpa_supplicant
CTRL: Invalid group 'wheel'
Failed to initialize control interface '/run/wpa_supplicant'.
You may have another wpa_supplicant process already running or the file was
left by an unclean termination of wpa_supplicant in which case you will need
to manually remove this file before starting wpa_supplicant again.

nl80211: deinit ifname=wlp3s0 disabled_11b_rates=0

When I run ps aux | grep wpa I see this running:

root      1124  0.0  0.1  44024  6392 ?        Ss   08:22   0:00 /sbin/wpa_supplicant -u -s -O /run/wpa_supplicant

Last time I tried to kill that process I got stuck in a situation where the computer wouldn't shut down.

More details:

$ uname -a
Linux butny 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

$ ifconfig
....
wlp3s0    Link encap:Ethernet  HWaddr e8:94:f6:10:bb:ee
      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)

$ wpa_supplicant -h
drivers:
  nl80211 = Linux nl80211/cfg80211
  wext = Linux wireless extensions (generic)
  wired = Wired Ethernet driver
  none = no driver (RADIUS server/WPS ER)

$ more /etc/wpa_supplicant/wpa_supplicant.conf
ctrl_interface=/run/wpa_supplicant
ctrl_interface_group=admin # group admin can use wpa_cli
update_config=1
network={
  ssid="<home>"
  psk="<password>"
}

Answer 1

The source of the problem seems to be in /etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=/run/wpa_supplicant
ctrl_interface_group=admin # group admin can use wpa_cli

CTRL: Invalid group 'wheel' Failed to initialize control interface '/run/wpa_supplicant'.

The group admin doesn't exists, you can try to replace it with group sudo which do exists in Ubuntu.

ctrl_interface=/run/wpa_supplicant
ctrl_interface_group=sudo 

or in group root which do exists in Ubuntu.

ctrl_interface=/run/wpa_supplicant
ctrl_interface_group=root