I am trying to use nginx as a load balancer for syslog, to be able to send logs to several downstream Graylog ingestors in order to help improve performance of the Graylog cluster.

I'm having trouble with the config, as I'm getting the error:
[error] 2813#2813: *210329 no live upstreams while connecting to upstream, udp client: 10.0.X.X, server: 0.0.0.0:11016, upstream: "port_11016_stream_backend", bytes from/to client:937/0, bytes from/to upstream:0/0

As a small example of my conf file, it looks like this:

stream {
server {
listen 11016 udp;
proxy_pass port_11016_stream_backend;
}

upstream port_11016_stream_backend {
server 10.0.X.Y:11016;
}
}

It's not going to receive any bytes back from the server because I want this to be UDP proxying, and ergo there will be no reply. How can I eliminate this error?

Hey facing similar situation. Was this solved?

Yes.

You have to set the proxy_responses field to 0.

So using my above example, it looks like:

stream {
server {
listen 11016 udp;
proxy_responses 0;
proxy_pass port_11016_stream_backend;
}

upstream port_11016_stream_backend {
server 10.0.X.Y:11016;
}
}

Hey thanks a lot. Will try that :)