feat(chart): add optional PodDisruptionBudget for php-fpm and nginx

kubernetes/glpi/templates/glpi-poddisruptionbudget.yaml

@@ -0,0 +1,42 @@
+{{- if .Values.glpi.phpfpm.pdb.enabled }}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: php-fpm
+  namespace: {{ include "glpi.namespace" . }}
+  labels:
+    {{- include "glpi.labels" . | nindent 4 }}
+    app.kubernetes.io/component: php-fpm
+spec:
+  {{- if .Values.glpi.phpfpm.pdb.minAvailable }}
+  minAvailable: {{ .Values.glpi.phpfpm.pdb.minAvailable }}
+  {{- else }}
+  maxUnavailable: {{ .Values.glpi.phpfpm.pdb.maxUnavailable }}
+  {{- end }}
+  selector:
+    matchLabels:
+      {{- include "glpi.selectorLabels" . | nindent 6 }}
+      app.kubernetes.io/component: php-fpm
+{{- end }}
+
+---
+{{- if .Values.glpi.nginx.pdb.enabled }}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: nginx
+  namespace: {{ include "glpi.namespace" . }}
+  labels:
+    {{- include "glpi.labels" . | nindent 4 }}
+    app.kubernetes.io/component: nginx
+spec:
+  {{- if .Values.glpi.nginx.pdb.minAvailable }}
+  minAvailable: {{ .Values.glpi.nginx.pdb.minAvailable }}
+  {{- else }}
+  maxUnavailable: {{ .Values.glpi.nginx.pdb.maxUnavailable }}
+  {{- end }}
+  selector:
+    matchLabels:
+      {{- include "glpi.selectorLabels" . | nindent 6 }}
+      app.kubernetes.io/component: nginx
+{{- end }}

kubernetes/glpi/values.yaml

@@ -67,6 +67,20 @@ glpi:
       periodSeconds: 5
       timeoutSeconds: 3
       failureThreshold: 3
+
+    # -- Pod Disruption Budget
+    # Only meaningful when phpfpm.replicaCount > 1: with a single replica, a PDB
+    # requiring minAvailable: 1 (or maxUnavailable: 0) will block voluntary node
+    # drains/evictions entirely, since Kubernetes can never satisfy it. Defaults to
+    # disabled for that reason; enable once you scale replicaCount up.
+    pdb:
+      enabled: false
+      # Minimum number/percentage of pods that must remain available (e.g. 1 or "50%").
+      # Leave empty to use maxUnavailable instead.
+      minAvailable: ""
+      # Maximum number/percentage of pods that may be unavailable (e.g. 1 or "50%").
+      # Ignored if minAvailable is set.
+      maxUnavailable: 1
 
   # Nginx container configuration
   nginx:
@@ -125,6 +139,14 @@ glpi:
       port: 80
       # Target port on the container
       targetPort: 8080
+
+    # -- Pod Disruption Budget
+    # Only meaningful when nginx.replicaCount > 1 - see the equivalent note under
+    # glpi.phpfpm.pdb.
+    pdb:
+      enabled: false
+      minAvailable: ""
+      maxUnavailable: 1
 
   # GLPI directory paths configuration
   paths: