docs: specify ServiceMonitor requirements in values.yaml (apache#585)

charts/apisix-ingress-controller/README.md

@@ -164,7 +164,7 @@ The same for container level, you need to set:
 | serviceAccount.automountServiceAccountToken | bool | `true` | Whether automounting API credentials for a service account |
 | serviceAccount.create | bool | `true` | Specifies whether a ServiceAccount should be created |
 | serviceAccount.name | string | `""` | The name of the ServiceAccount to use. If not set and create is true, a name is generated using the fullname template |
-| serviceMonitor | object | `{"annotations":{},"enabled":false,"interval":"15s","labels":{},"metricRelabelings":{},"namespace":"monitoring"}` | namespace: "ingress-apisix" |
+| serviceMonitor | object | `{"annotations":{},"enabled":false,"interval":"15s","labels":{},"metricRelabelings":{},"namespace":"monitoring"}` | Enable creating ServiceMonitor objects for Prometheus operator. Requires Prometheus operator v0.38.0 or higher. |
 | serviceMonitor.annotations | object | `{}` | @param serviceMonitor.annotations ServiceMonitor annotations |
 | serviceMonitor.labels | object | `{}` | @param serviceMonitor.labels ServiceMonitor extra labels |
 | serviceMonitor.metricRelabelings | object | `{}` | @param serviceMonitor.metricRelabelings MetricRelabelConfigs to apply to samples before ingestion. ref: https://prometheus.io/docs/prometheus/latest/configuration/configuration/#metric_relabel_configs |

charts/apisix-ingress-controller/values.yaml

@@ -182,8 +182,10 @@ affinity: {}
 # ref: https://kubernetes.io/docs/concepts/workloads/pods/pod-topology-spread-constraints/#spread-constraints-for-pods
 topologySpreadConstraints: []
 
-# -- namespace: "ingress-apisix"
+#  namespace: "ingress-apisix"
 
+# -- Enable creating ServiceMonitor objects for Prometheus operator.
+# Requires Prometheus operator v0.38.0 or higher.
 serviceMonitor:
   enabled: false
   namespace: "monitoring"