Hello,

A self contained solution would be to double proxy, first through nginx stream server and then locally back to nginx http server (with proxy_pass via unix socket, or to localhost on a different port).

You can implement your own custom rate limiting logic in the stream server with NJS (js_access) and use the new js_shared_dict_zone (which is shared between workers) for persistently storing rate calculations.

You'd have additional overhead from the stream tcp proxy and the njs, but it shouldn't be too great (at least compared to overhead of TLS handshakes).

Regards,
Jordan Carter.

________________________________________
From: nginx <nginx-bounces@nginx.org> on behalf of Zero King <l2dy@aosc.io>
Sent: Saturday, November 18, 2023 6:44 AM
To: nginx@nginx.org
Subject: Limiting number of client TLS connections

Hi all,

I want Nginx to limit the rate of new TLS connections and the total (or
per-worker) number of all client-facing connections, so that under a
sudden surge of requests, existing connections can get enough share of
CPU to be served properly, while excessive connections are rejected and
retried against other servers in the cluster.

I am running Nginx on a managed Kubernetes cluster, so tuning kernel
parameters or configuring layer 4 firewall is not an option.

To serve existing connections well, worker_connections can not be used,
because it also affects connections with proxied servers.

Is there a way to implement these measures in Nginx configuration?
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