I have since solved this issue.
@samothx
Thanks for you help you really pushed me in the right direction with a udev rule, I just needed to make it less specific for fleet wide deployment.
Sets to get a secondary (or primary if it supports it and you have a wired connection) wireless adapter into monitor mode from within a container.
First check if your adapter supports it.
iw list will output the supported modes if you can’t grep for monitor it won’t work.
Second, configure the network manager to not touch it.
find / -name "NetworkManager.conf"
-To find all version of the NetworkManger config
-You want the one that is on the long path like this:
/mnt/sysroot/active/balena/aufs/diff/somerandomhashtthatisdevicespecificbestIcantell/etc/NetworkManager/NetworkManager.conf
then:
echo -e "[device]\nwifi.scan-rand-mac-address=no\n[keyfile]\nunmanaged-devices=interface-name:wlan9" >> $thepathyourfound/NetworkManager.conf
Those additions one stop it from changing Mac address which can affect the next step and two stop it from interfering with our new monitoring interface wlan9 which we will set up in the next step.
Sources:here and here
Now for udev rules:
Source for more info: Best source ever
You can edit your config.json a variety of ways, just make sure you change the one that will be loaded on reboot. The easiest way is to plug it into a machine and access the belena_boot partition directly.
However, note if you mess up the json formatting your device will not boot, so try this on devices you have physical access to.
Mostly follow the guild to get something you can use to id the device with. @samothx used the address in their example but that is too specific for me so I used the driver:
"os":{"udevRules":{"11":"SUBSYSTEM==\"net\", ACTION==\"add\", DRIVERS==\"rt2800usb\", NAME=\"wlan9\""}},
See the documentation on this for more help or push me to add more detail.
Lastly, now that you can see your device has been named wlan9 after a reboot with iwconfig (probably in a container)
From within a container with the right network tools installed, look up for your distribution what you need.
ip link set wlan9 down
iw wlan9 set monitor control
ip link set wlan9 up
And that should do it!
-Thomas