How to enable disable HAproxy backend server nodes in Linux RHEL CentOS

Enabling and disabling HAproxy backend server option not comes with default installation. Therefore we have setup a way to do it ourselves.

Below is how I do enable and disable servers without restarting whole HAproxy server. I have configured unix socket and used socat command to enable disable servers.

Therefore if not already installed you need to install socat in your linux machine. I use yum command since I am using RHEL,

After installing socat, you need to enable stats socket in the haproxy configuration file as mentioned below,

( For more information check on http://www.haproxy.org/download/1.5/doc/configuration.txt url and go 

the “9.2. Unix Socket commands section” ).

global

        stats socket /var/run/haproxy.sock mode 600 level admin

        stats timeout 2m

Save haproxy configuration and restart haproxy service,

#systemctl restart haproxy.service

Now you can enable or disable your server by using below commands,

[root@localhost ~]# echo "enable server <your backend name>/<server name in 

                 HAproxy configuration>" | socat stdio /var/run/haproxy.sock

[root@localhost ~]# echo "disable server <your backend name>/<server name in 

                  HAproxy configuration>" | socat stdio /var/run/haproxy.sock

That’s all. You can check whether server is enabled or disabled via haproxy stats page,

http://<serverIP>:<statPort>/haprxy?stats