(Disclaimer: I work for HAProxy Technologies)
HAProxy now supports Syslog and DNS load balancing. For generalized UDP load balancing, we typically recommend using LVS for UDP while using HAProxy for HTTP / TCP. See the discussion on UDP support here: UDP Loadbalancing · Issue #62 · haproxy/haproxy · GitHub
For those who do not want to use LVS, HAProxy Enterprise 2.9+ supports UDP load balancing with a native module.
Links:
- Documentation: Load balance UDP with HAProxy Enterprise | HAProxy Enterprise
- UDP solution information: HAProxy UDP Load Balancing Solutions