Templating prometheus url into cronjob heartbeat (#11343)

Can not use external prometheus with hearbeat. This change adds a new variable `.prometheusUrl` in value and use it into heartbeat from linkerd-control-plane chart.

Fixes #11342

Signed-off-by: David ALEXANDRE <[email protected]>

Author: david972

charts/linkerd-control-plane/templates/heartbeat.yaml

@@ -64,7 +64,11 @@ spec:
             - "-controller-namespace={{.Release.Namespace}}"
             - "-log-level={{.Values.controllerLogLevel}}"
             - "-log-format={{.Values.controllerLogFormat}}"
+            {{- if .Values.prometheusUrl }}
+            - "-prometheus-url={{.Values.prometheusUrl}}"
+            {{- else }}
             - "-prometheus-url=http://prometheus.linkerd-viz.svc.{{.Values.clusterDomain}}:9090"
+            {{- end }}
             {{- if .Values.heartbeatResources -}}
             {{- include "partials.resources" .Values.heartbeatResources | nindent 12 }}
             {{- end }}

charts/linkerd-control-plane/values.yaml

@@ -502,7 +502,7 @@ policyValidator:
   # for more information.
   injectCaFromSecret: ""
 
-# -|- CPU, Memory and Ephemeral Storage resources required by the policy controller 
+# -|- CPU, Memory and Ephemeral Storage resources required by the policy controller
 #policyControllerResources:
 
 # -- NodeSelector section, See the [K8S
@@ -525,6 +525,9 @@ nodeSelector:
 # for more information
 #nodeAffinity:
 
+# -- url of external prometheus instance (used for the heartbeat)
+prometheusUrl: ""
+
 # Prometheus Operator PodMonitor configuration
 podMonitor:
   # -- Enables the creation of Prometheus Operator [PodMonitor](https://prometheus-operator.dev/docs/operator/api/#monitoring.coreos.com/v1.PodMonitor)