HAProxy Enterprise Documentation 2.3r1

TCP Health Checks

A basic TCP-layer health check tries to connect to the server's TCP port. The check is valid when the server answers with a SYN/ACK packet. Enable it by adding a check parameter to each server line that you would like to monitor.

In the following example, the load balancer tries to connect to port 80 on each server:

backend be_myapp
   server srv1 10.0.0.1:80 check
   server srv2 10.0.0.2:80 check

To send health check probes to a port other than the one to which normal traffic is sent, add the port parameter. In the following example, the health check is sent to port 8080.

backend be_myapp
   server srv1 10.0.0.1:80 check port 8080
   server srv2 10.0.0.2:80 check port 8080

Next up

HTTP Health Checks