Yesterday, for around 10 minutes, my haproxy served a lot of 503 pages (directly from
errorfile 503 /etc/haproxy/errors/503.http) and I don't know why. I have no health checks to my backends, so for sure these were not marked as disabled. The stats page doesn't show that a limit was reached (in the marked red areas).
global maxconn 20000 tune.ssl.default-dh-param 2048 daemon ... defaults log global mode http timeout http-request 30s option httplog option dontlognull timeout connect 5s timeout server 120s timeout client 30s ... frontend frontend_for_all_sites maxconn 20000 mode http bind *:80 option http-buffer-request timeout http-request 30s ... use_backend www_backend if acl_hostname_www use_backend static_backend if acl_hostname_static backend www_backend option forwardfor server www localhost:9090 maxconn 5000 backend static_backend option forwardfor server s localhost:9090 maxconn 5000
Where should I look at next to figure out why did that happen?