fix default non-ha state for alert-manager statefulset (#22350)

Signed-off-by: Tuan Anh Nguyen <tuananh.nguyen-ext@commercetools.de>

stable/prometheus/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: prometheus
-version: 11.2.0
+version: 11.2.1
 appVersion: 2.18.1
 description: Prometheus is a monitoring system and time series database.
 home: https://prometheus.io/

stable/prometheus/README.md

@@ -165,7 +165,7 @@ Parameter | Description | Default
 `alertmanager.statefulSet.podManagementPolicy` | podManagementPolicy of alertmanager pods | `OrderedReady`
 `alertmanager.statefulSet.headless.annotations` | annotations for alertmanager headless service | `{}`
 `alertmanager.statefulSet.headless.labels` | labels for alertmanager headless service | `{}`
-`alertmanager.statefulSet.headless.enableMeshPeer` | If true, enable the mesh peer endpoint for the headless service | `{}`
+`alertmanager.statefulSet.headless.enableMeshPeer` | If true, enable the mesh peer endpoint for the headless service | `false`
 `alertmanager.statefulSet.headless.servicePort` | alertmanager headless service port | `80`
 `alertmanager.priorityClassName` | alertmanager priorityClassName | `nil`
 `alertmanager.resources` | alertmanager pod resource requests & limits | `{}`

stable/prometheus/templates/alertmanager-statefulset.yaml

@@ -55,6 +55,8 @@ spec:
           {{- range $n := until (.Values.alertmanager.replicaCount | int) }}
             - --cluster.peer={{ template "prometheus.alertmanager.fullname" $ }}-{{ $n }}.{{ template "prometheus.alertmanager.fullname" $ }}-headless:6783
           {{- end }}
+          {{- else }}
+            - --cluster.listen-address=""
           {{- end }}
           {{- range $key, $value := .Values.alertmanager.extraArgs }}
             - --{{ $key }}={{ $value }}