Commit 4f168972 authored by Committed by Łukasz Nowak
caddy-frontend: Fix random 502 EOFs by adding try_duration
try_duration and try_interval are Caddy proxy's switches which allow to deal with non working backend (https://caddyserver.com/docs/proxy) The non working backend is the one, to which connection is lost or was not possible to make, without sending any data. The default try_duration=5s and try_interval=250ms are chosen, so that in normal network conditions (with all possible problems in the network, like lost packets) the browser will have to wait up to 5 seconds to be informed that backend is inaccessible or for the request to start being processed, but only a bit more than 250ms if Caddy would have to reestablish connection to faulty backend. In order to check it out it is advisable to setup a system, with real backend, like apache one, and configure iptables to randomly reject packets to it: iptables -A INPUT -m statistic --mode random -p tcp --dport <backend_port> \ --probability 0.05 -j REJECT --reject-with tcp-reset Using ab or any other tool will results with lot of 502 EOF in the Caddy error log and also reported by ab. With this configuration there are no more errors visible to the client, which come from the problems on the network between Caddy and the backend.
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