Skip to content

Statistics & traffic

Statistics

Statistics reads HAProxy's admin socket (show stat) and refreshes every five seconds:

  • Listeners — status, current/max/total sessions, request rate, bytes in and out, denied requests and errors.
  • Each pool — its own status, how many servers are up, and per server: state (UP / DOWN / MAINT / DRAIN / NOLB) with how long it has held it, active or backup, weight, sessions, queue, traffic, the last health check result (L7OK, L4CON, …) with its duration, failed-check and flap counts, and total downtime.

A server with health checking switched off reports no check and counts as up, because HAProxy still routes to it.

Traffic history

The Traffic card: a day of requests per pool, with server errors drawn over them

The Statistics page shows what is happening now; the Traffic card on it shows what happened. Once a minute each node records, per pool, how many requests it served and how many server errors it returned, and keeps a day of it — enough to answer when did this start, which a live gauge cannot.

The Services page carries the same thing as a sparkline per service, with server errors drawn over the requests, because the question is always whether they happened at the same time.

It is per node and only covers time the app was running: a gap in the line is a gap in the recording, not in the traffic. Counts are per minute rather than totals, and a counter that goes backwards is treated as HAProxy having restarted rather than as negative traffic.

The traffic this app generates itself is not counted. The once-a-minute URL probes go through HAProxy on purpose — that is what makes them honest — so HAProxy counts them like anyone else's requests, and a service nobody visits would show a steady line of the app talking to itself. The history subtracts what the probes put through, including the 401 a sign-in answers a probe with, so zero visitors reads as zero. (HAProxy's backend health checks were never in these numbers — HAProxy accounts for them separately.)

The charts cannot overstate a trickle. A sparkline scaled purely to its own peak turns a flat 1 request a minute into a solid block that reads as more traffic than a real rush on the row above it. The scale therefore never drops below 10 requests a minute: a trickle draws as the low band it is, and anything actually busy still gets its own scale. Server errors are drawn on the same scale as the requests, for the same reason.