MINOR: Support PodMonitor as alternative to ServiceMonitor

Signed-off-by: Philipp Hossner <[email protected]>

kubernetes-ingress/README.md

@@ -194,6 +194,22 @@ helm install my-ingress haproxytech/kubernetes-ingress \
   --set controller.serviceMonitor.enabled=true
 ```
 
+### Installing the PodMonitor
+
+As an alternative to a `ServiceMonitor` you can use a `PodMonitor`, which targets the pods directly instead of using a service.
+If you're using the [Prometheus Operator](https://github.com/prometheus-operator/prometheus-operator), you can automatically install the `PodMonitor` definition in order to automate the scraping options according to your needs.
+
+```console
+helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
+
+helm install prometheus prometheus-community/kube-prometheus-stack \
+  --set prometheus.prometheusSpec.podMonitorSelectorNilUsesHelmValues=false \
+  --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false
+
+helm install my-ingress haproxytech/kubernetes-ingress \
+  --set controller.podMonitor.enabled=true
+```
+
 ### Installing with Kubernetes Event-driven Autoscaling (KEDA)
 
 [KEDA](https://keda.sh/docs/2.3/concepts/scaling-deployments/) is an improved scaling solution built on top of HPA which allows autoscaling criteria based on information from any event source including Prometheus metrics collected from HAProxy native Prometheus Exporter.

kubernetes-ingress/ci/deployment-podmonitor-values.yaml

@@ -0,0 +1,6 @@
+controller:
+  strategy:
+    type: RollingUpdate
+    rollingUpdate:
+      maxUnavailable: 0
+      maxSurge: 1

kubernetes-ingress/templates/_helpers.tpl

@@ -145,6 +145,13 @@ Create a default fully qualified ServiceMonitor name.
 {{- default (include "kubernetes-ingress.fullname" .) .Values.controller.serviceMonitor.nameOverride | trunc 63 | trimSuffix "-" -}}
 {{- end -}}
 
+{{/*
+Create a default fully qualified PodMonitor name.
+*/}}
+{{- define "kubernetes-ingress.podMonitorName" -}}
+{{- default (include "kubernetes-ingress.fullname" .) .Values.controller.podMonitor.nameOverride | trunc 63 | trimSuffix "-" -}}
+{{- end -}}
+
 {{/*
 Create a FQDN for the Service metrics.
 */}}

kubernetes-ingress/templates/controller-podmonitor.yaml

@@ -0,0 +1,42 @@
+{{/*
+Copyright 2024 HAProxy Technologies LLC
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/}}
+
+{{- if and (.Capabilities.APIVersions.Has "monitoring.coreos.com/v1") .Values.controller.podMonitor.enabled }}
+apiVersion: monitoring.coreos.com/v1
+kind: PodMonitor
+metadata:
+  name: {{ include "kubernetes-ingress.podMonitorName" . }}
+  namespace: {{ include "kubernetes-ingress.namespace" . }}
+  labels:
+    app.kubernetes.io/name: {{ include "kubernetes-ingress.name" . }}
+    helm.sh/chart: {{ include "kubernetes-ingress.chart" . }}
+    app.kubernetes.io/managed-by: {{ .Release.Service }}
+    app.kubernetes.io/instance: {{ .Release.Name }}
+    app.kubernetes.io/version: {{ .Chart.AppVersion }}
+    {{- if .Values.controller.podMonitor.extraLabels }}
+    {{ toYaml .Values.controller.podMonitor.extraLabels | nindent 4 }}
+    {{- end }}
+spec:
+  podMetricsEndpoints:
+    {{ .Values.controller.podMonitor.endpoints | toYaml | nindent 4 }}
+  namespaceSelector:
+    matchNames:
+    - {{ include "kubernetes-ingress.namespace" . }}
+  selector:
+    matchLabels:
+      app.kubernetes.io/name: {{ include "kubernetes-ingress.name" . }}
+      app.kubernetes.io/instance: {{ .Release.Name }}
+{{- end }}

kubernetes-ingress/values.yaml

@@ -563,6 +563,7 @@ controller:
   ##   --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false
   serviceMonitor:
     ## Toggle the ServiceMonitor true if you have Prometheus Operator installed and configured
+    ## Should not be enabled when controller.podMonitor.enabled is true
     enabled: false
 
     ## Specify the labels to add to the ServiceMonitors to be selected for target discovery
@@ -576,6 +577,28 @@ controller:
         scheme: http
         interval: 30s
 
+  ## PodMonitor
+  ## ref: https://github.com/prometheus-operator/prometheus-operator/blob/master/Documentation/user-guides/getting-started.md
+  ## Note: requires Prometheus Operator to be able to work, for example:
+  ## helm install prometheus prometheus-community/kube-prometheus-stack \
+  ##   --set prometheus.prometheusSpec.podMonitorSelectorNilUsesHelmValues=false \
+  ##   --set prometheus.prometheusSpec.serviceMonitorSelectorNilUsesHelmValues=false
+  podMonitor:
+    ## Toggle the PodMonitor true if you have Prometheus Operator installed and configured
+    ## Should not be enabled when controller.serviceMonitor.enabled is true
+    enabled: false
+
+    ## Specify the labels to add to the PodMonitors to be selected for target discovery
+    extraLabels: {}
+
+    ## Specify the endpoints
+    ## ref: https://github.com/prometheus-operator/prometheus-operator/blob/master/Documentation/design.md#podMonitor
+    endpoints:
+      - port: stat
+        path: /metrics
+        scheme: http
+        interval: 30s
+
   ## Controller sync mode with Kubernetes
   ## Note: requires Enterprise Kubernetes Ingress Controller
   ## Possible values: 'default' or 'fetch'