✅ RECOMMENDED

Here is a practical example for deploying the HAProxy's native TCP-based check option.

#---------------------------------------------------------------------
# backend
#---------------------------------------------------------------------
listen connector
    bind *:3306
    mode tcp
    option tcpka   # enables keep-alive both on client and server side
    balance roundrobin
    server conn1 db1:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000
    server conn2 db2:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000
    server conn3 db3:3306 check inter 5s rise 1 fall 1 weight 3 maxconn 5000

This solution does NOT require adding a user to MySQL.