The Metrics service consists of three parts:
The "Master metrics" runs the "Worker metrics" when metrics collection has been activated. Master runs on worker per service: one for HAProxy service, one for WAF. The "Master metrics" should be running always.
When you would like to start collecting HAProxy service metrics the "Master metrics" will start local worker for every HAProxy service. The "Worker metrics" will check every HAProxy service remotely by 1999 port(by default). If you would like to use the metrics service and if HAProxy service has been installed manually read how you should set HAProxy service.
For Metrics installation you should run:
How to start using RPM you can read in this article
The "Master metrics" and "Worker metrics" Logs
The "Master metrics" and "Worker metrics" have their own log in an "Internal logs". You can read more about the "Internal logs" here