Support for differentiating multiple clusters

[gorantornqvist]

Motivation

It appears to be only possible to specify one channel for alerts but we have 3 different clusters so we would like to send messages to different channels.
Alternatively if only one channel has to be used , there is no way to see from which cluster an alert comes from, example:

Default
Status
:fire: FIRING :fire:

summary	description
Job failed to complete.

Job openshift-logging/curator-1625119680 failed to complete. Removing failed job after investigation should clear this alert.

severity	alertname
warning

KubeJobFailed

condition	container
true

kube-rbac-proxy-main

namespace	prometheus
openshift-logging

openshift-monitoring/k8s

service	endpoint
kube-state-metrics

https-main

job	job_name
kube-state-metrics

curator-1625119680

Start At
2 days 3 hours 31 minutes 33 seconds 61 milliseconds 452 microseconds

Ended At
292 years 24 weeks 3 days 23 hours 47 minutes 16 seconds 854 milliseconds 775 microseconds

[gorantornqvist]

A quick workaround was to change receiver from Default to ClusterName_Default ...