Haproxy socket stats

Enable stats

Reporting is provided if you enable stats into its config.

The setting is described at https://cbonte.github.io/haproxy-dconv/1.8/configuration.html#4.2-stats%20enable

In this post I describe how to use the socket type.

Enable the stats socket

I enable it into the global section as so

global

  stats socket /var/lib/haproxy/stats group haproxy mode 664

What this does is:

• enable the stats socket under /var/lib/haproxy/stats
• the group owner is haproxy (running haproxy as user haproxy)
• permissions are rw (user), rw(group), r(others)

Note there is an option admin that will allow to control haproxy but I don’t use it.

Reading stats from socket (netcat)

You need to have installed netcat (nc).

$ echo 'show stat' | nc -U /var/lib/haproxy/stats
# pxname,svname,qcur,qmax,scur,smax,slim,
....
http_frontend,
....

Reading stats from socket (socat)

You need to install socat since is not frequently installed.

To use it

$ echo 'show stat' | socat stdio /var/lib/haproxy/stats
# pxname,svname,qcur,qmax,scur,smax,slim,
....
http_frontend,
....

Netcat HTTP server

Netcat is a very versatile program used for network communications - the place to find it is .

Often I need to test different programs with a dummy HTTP server, so using netcat for this is very easy.

Lt's say you want to respond with HTTP code 200 ... this is what you do with netcat into a shell

 nc -k  -lp 9000 -c 'echo "HTTP/1.1 200 OK\nContent-Length:0\nContent-Type: text/html; charset=utf-8"' -vvv -o session.txt

To explain the switches used:

• -k accept multiple connections, won't stop netcat after first connection(default)
• -l listen TCP on the all interfaces
• -p the port number to bind
• -c 'echo "HTTP/1.1 200 OK\nContent-Length:0\nContent-Type: text/html; charset=utf-8"' is the most interesting one ... this responds back to the client with a minimal http header and sets code 200 OK
• -vvv verbosity level
• -o session.txt netcat will write into this file all the input and output

Now you have a dummy http server running on port 9000 that will answer 200 OK ALL the time :)