Docker and native SNMPd

Installing and Using OpenWrt
1

Ok, this one has me stumped.

I have OpenWRT v24.10.0-rc2 on x86_64, I installed docker w/ opkg install luci-app-dockerman and then successfully loaded and configured my docker container. All is well on that side.

The issue I'm having is that I noticed my snmpd client application acted like the server (OpenWRT) stopped responding. I rebooted OpenWRT, still broken. I shutdown my docker container, restarted snmpd, and it works fine. I start my docker container, and it stops working.

For reference, I have snmpd, not mini_snmpd. Can anyone think of why this might be? I am stumped here.

EDIT: some more info, I have been looking into it further, I installed mini_snmpd and it seems to work OK w/ the docker container running, however I can't seem to get it to give info about my RNDIS eth1 adapter. The config file says to use the UCI name and when I do, all interfaces no longer work in my client.

FINAL EDIT:
After playing around a bit, I discovered that my client would break if the interfaces were labeled as having speeds > 1Gbps. The virtual interfaces docker0 and vethxxxxxxx were both coming through as 10Gbps. This is why the docker container broke my SNMP client. The fix, through crude was the following:

Edit /etc/init.d/snmpd and add the following line in the iface for-loop:

for iface in $(ls /sys/class/net 2>/dev/null); do
        echo interface "$iface" 6 0 >> $CONFIGFILE
        procd_append_param netdev "$iface"
done

This makes snmpd set all known interfaces to 0Mbps on startup. Recall that vethxxxxxxx is dynamic and changes each time a docker container launches, so we can't just add one static interface to the $CONFIGFILE and be done w/ it.

Next write a custom hotplug.d script to restart snmpd anytime a vethxxxxxxx interface is added.

Create /etc/hotplug.d/net/99-snmp-fix

#!/bin/sh

[ "$ACTION" = add ] && {
  isRight=$(echo $DEVICENAME | grep -c "veth")
  If [ isRight > 0 ] {
  sleep 5
  /etc/init.d/snmpd restart
  }
}

This makes snmpd restart when the vethxxxxxxx interface is added on docker container start.

Like I say, it's crude, but it's working... docker may have a place to put a bash script that launches on startup too, if you wanna go that way.