prometheus, grafana, alertmanager: number of alerts

 prometheus alerts counts

from : https://jaanhio.me/blog/visualizing-alerts-metrics-grafana/ + https://community.grafana.com/t/how-to-get-the-time-range-selected-on-the-dashboard-into-a-variable/2868/3

(sum by (alertname) (changes(ALERTS_FOR_STATE[$__range]) AND ignoring(alertstate) max_over_time(ALERTS{alertstate="firing"}[$__range])) + (count by (alertname) (changes(ALERTS_FOR_STATE[$__range]) AND ignoring(alertstate) max_over_time(ALERTS{alertstate="firing"}[$__range])) * 1))

Then use a grafana panel as "Gauge" with the following options :

* Value options: show calculate, Last *

* Orientation = horizontal, and 

Number of alerts by alert name of the last 2 months

PromQL = sum by(alertname) (changes(ALERTS_FOR_STATE[65d]))

Number of alerts by instance over the last 2 months

PromQL = sum by(instance_name) (changes(ALERTS_FOR_STATE[65d]))