Monitor Application Gateway Load
Provide a way to monitor Application Gateway CPU/Memory in order to track load. It's hard to know only based on current access/http errors when the WAF is under heavy preasure and we need to scale it up.
There is no plan currently to offer these system level metrics for Application Gateway Standard (V1). However, we are planning to offer more observability with our new Autoscaling version (V2) of Application Gateway/WAF. We already offer Capacity Units as a metric which gives you a sense of the traffic load on your Application Gateway. More are planned for V2. Please send in your specific feedback via https://aka.ms/ApplicationGatewayCohort
Marcin Koperski (CIN) commented
We had an issue with Application Gateway v2 where autoscaling didn't work under heavy load. There was absolutely no indication neither the AG was overloaded nor the autoscaling failed. CPU metrics and number of currently running instances is a must.