System frequently stops responding...

[Mohamed Lrhazi]

Hello,

Run into an issue today, which digging in the logs seems to have going on
for a while, but somehow became extreme today... Not sure yet what the root
cause is.. might not be FreeRADIUS.

I have four instances of 3.0.8, running in containers, two per VM. a load
balancer routes traffic to the nodes, with username based persistence.

We have several Cisco wireless controllers that use this RAIDUS setup....
very frequently, they have been logging that the RADIUS server failed to
respond, and log the user name and the station id. I tracked lots of such
instances, and found the packets do arrive at the VMs, but no reply is sent
out. Sometime later system would respond fine to some other incoming
packets!

I find nothing in the logs related the failed requests, not
from FreeRADIUS and not from iptables...

The load on the VMs is constantly close to 0. No RAM issues or any other
issues I could see...

I doubled the number of FreeRADIUS instances anyway... but the issue
persisted. the Cisco's log the errors many times per minute....

I restarted the FreeRADIUS instances few times... to no avail. But then
decided to reboot both VMs... and issue seems to have disappeared! At least
for now. the uptime on the VMs was 92 days. they are redhat 6.6.


any suggestions on how to further debug such behavior, if it were to start
again?

Thanks a lot,
Mohamed.