Status-Server requests are blocked if an Access-Request is waiting for downstream service to respond

[Ignacio Arces]

Hello,

I'm running a containerized FreeRADIUS server v3.0.19 with a custom
authentication module written in C language that authenticates users
through a HTTP API. I also configured the Status server as detailed in
https://wiki.freeradius.org/config/Status and I'm using it to monitor my
server by sending Server-Status requests using raclient to health check my
server.

We recently experienced an outage in the auth API and since we didn't have
timeouts properly configured in the curl calls in our custom C module, the
requests were hanging indefinitely. When this happened, we also noticed
that our containerized server was restarted by Docker as the container was
set to "Unhealthy" state, so the health checks were failing.
Troubleshooting the health checks we found that Status-Server requests were
not responding while the auth request was hanging waiting for the auth API
to respond.

Now that we have a 10s timeout properly configured in our curl requests, we
have mitigated the undesired restarts but we still can understand why even
a single stuck auth request is impacting Status-Server request.