internal metrics (#5011)

Signed-off-by: Venkat Ramaraju <[email protected]>

Author: VenkatRamaraju

website/content/en/docs/building-operators/ansible/reference/internal_metrics.md

@@ -0,0 +1,16 @@
+The Ansible Operator comes with three internal metrics that provide an insight to the frequency and time of operator reconciliations. These metrics can be
+scraped by a Prometheus instance or any other openmetrics system. To publish operator metrics and scrape them with an openmetrics system such as Prometheus, view 
+[Kubebuilder documentation](https://book.kubebuilder.io/reference/metrics.html) on publishing metrics.
+
+The default metrics recorded in Operator SDK are collected in a [histogram](https://prometheus.io/docs/practices/histograms/).
+
+The following three metrics are derived from the histogram:
+1. `ansible_operator_reconciles_bucket` - Each bucket in the histogram counts the number of reconciliations that have a period (in seconds) less than or equal
+to the upper limit of the bucket.
+3. `ansible_operator_reconciles_count` - The total number of reconciliations that have occured up to that instance of time while running an Ansible operator.
+4. `ansible_operator_reconciles_sum` - The cumulative amount of time (in seconds) of all reconciliations that have occured up to that instance of time while 
+running an Ansible operator.
+
+These metrics can be queried in the Prometheus UI.
+
+![Screen Shot 2021-06-24 at 2 10 28 PM](https://user-images.githubusercontent.com/37827279/123332879-f0fb2900-d4f5-11eb-87ea-7afd04f35b1c.png)