Merge pull request #58 from simonpasquier/add-ocp-alerting

Add OCP alerting section

content/Products/OpenshiftMonitoring/alerting.md

@@ -0,0 +1,34 @@
+# Alerting guidelines
+
+Please refer to the [Alerting Consistency](https://github.com/openshift/enhancements/blob/master/enhancements/monitoring/alerting-consistency.md) OpenShift enhancement proposal for the recommendations applying to OCP built-in alerting rules.
+
+## Identifying alerting rules without a namespace label
+
+The enhancement proposal mentioned above states the following for OCP built-in alerts:
+
+> Alerts SHOULD include a namespace label indicating the source of the alert.
+
+Unfortunately this isn't something that we can verify by static analysis because the namespace label can come from the PromQL result or be added statically. Nevertheless we can still use the Telemetry data to identify OCP alerts that don't respect this statement.
+
+First, create an OCP cluster from the latest stable release. Once it is installed, run this command to return the list of all OCP built-in alert names:
+
+```bash
+curl -sk -H "Authorization: Bearer $(oc create token prometheus-k8s -n openshift-monitoring)" \
+https://$(oc get routes -n openshift-monitoring thanos-querier -o jsonpath='{.status.ingress[0].host}')/api/v1/rules \
+| jq -cr '.data.groups | map(.rules) | flatten | map(select(.type =="alerting")) | map(.name) | unique |join("|")'
+```
+
+Then from https://telemeter-lts.datahub.redhat.com, retrieve the list of all alerts matching the names that fired without a namespace label, grouped by minor release:
+
+```
+count by (alertname,version) (
+  alerts{alertname=~"<insert the list of names returned by the previous command>",namespace=""} *
+  on(_id) group_left(version) max by(_id, version) (
+    label_replace(id_version_ebs_account_internal:cluster_subscribed{version=~"4.\d\d.*"}, "version", "$1", "version", "^(4.\\d+).*$")
+  )
+)
+```
+
+You should now track back the non-compliant alerts to their component of origin and file bugs against them ([example](https://issues.redhat.com/browse/OCPBUGS-17191)).
+
+The exercise should be done at regular intervals, at least once per release cycle.