[samcrawford]

Great write-up! One question I had was around the use of keepalives. There's no mention in the article of whether keepalives were used between the client and reverse proxy, and no mention of whether it was used between the reverse proxy and backend.

I know Nginx doesn't use keepalives to backends by default (and I see it wasn't setup in the optimised Nginx proxy config), but it looks like Caddy does have keepalives enabled by default.

Perhaps that could explain the delta in failure rates, at least for one case?

[mholt]

Are you talking about HTTP keepalive or TCP keepalive?

Keepalives can actually reduce the performance of a server with many concurrent clients (i.e. a benchmark test), and have other weird effects on benchmarks: https://www.nginx.com/blog/http-keepalives-and-web-performan...

[teknopaul]

Same thing. Http has no keep alive feature, you don't send http keep alive requests, if http 1.1 asks for keepalives it's a tcp thing.

[mholt]

They are distinct in Go. The standard library uses "HTTP keep-alive" to mark connections as idle based on most recent HTTP request, whereas TCP keep-alive checks only ACKs.

[skyde]

http 2.0 has keep alive!