Chart: Add defaultBackend.maxUnavailable. (kubernetes#11995)

Author: Gacko

charts/ingress-nginx/README.md

@@ -516,7 +516,7 @@ As of version `1.26.0` of this chart, by simply not providing any clusterIP valu
 | defaultBackend.livenessProbe.periodSeconds | int | `10` |  |
 | defaultBackend.livenessProbe.successThreshold | int | `1` |  |
 | defaultBackend.livenessProbe.timeoutSeconds | int | `5` |  |
-| defaultBackend.minAvailable | int | `1` | Minimum available pods set in PodDisruptionBudget. |
+| defaultBackend.minAvailable | int | `1` | Minimum available pods set in PodDisruptionBudget. Define either 'minAvailable' or 'maxUnavailable', never both. |
 | defaultBackend.minReadySeconds | int | `0` | `minReadySeconds` to avoid killing pods before we are ready # |
 | defaultBackend.name | string | `"defaultbackend"` |  |
 | defaultBackend.networkPolicy.enabled | bool | `false` | Enable 'networkPolicy' or not |

charts/ingress-nginx/templates/default-backend-poddisruptionbudget.yaml

@@ -20,6 +20,10 @@ spec:
     matchLabels:
       {{- include "ingress-nginx.selectorLabels" . | nindent 6 }}
       app.kubernetes.io/component: default-backend
+  {{- if and .Values.defaultBackend.minAvailable (not (hasKey .Values.defaultBackend "maxUnavailable")) }}
   minAvailable: {{ .Values.defaultBackend.minAvailable }}
+  {{- else if .Values.defaultBackend.maxUnavailable }}
+  maxUnavailable: {{ .Values.defaultBackend.maxUnavailable }}
+  {{- end }}
 {{- end }}
 {{- end }}

charts/ingress-nginx/tests/default-backend-poddisruptionbudget_test.yaml

@@ -46,3 +46,20 @@ tests:
     asserts:
       - hasDocuments:
           count: 0
+
+  - it: should create a PodDisruptionBudget without `minAvailable` and with `maxUnavailable` if `defaultBackend.minAvailable` and `defaultBackend.maxUnavailable` are set
+    set:
+      defaultBackend.enabled: true
+      defaultBackend.replicaCount: 2
+      defaultBackend.minAvailable: 1
+      defaultBackend.maxUnavailable: 1
+    asserts:
+      - hasDocuments:
+          count: 1
+      - isKind:
+          of: PodDisruptionBudget
+      - notExists:
+          path: spec.minAvailable
+      - equal:
+          path: spec.maxUnavailable
+          value: 1

charts/ingress-nginx/values.yaml

@@ -1097,7 +1097,11 @@ defaultBackend:
   podAnnotations: {}
   replicaCount: 1
   # -- Minimum available pods set in PodDisruptionBudget.
+  # Define either 'minAvailable' or 'maxUnavailable', never both.
   minAvailable: 1
+  # -- Maximum unavailable pods set in PodDisruptionBudget. If set, 'minAvailable' is ignored.
+  # maxUnavailable: 1
+
   resources: {}
   # limits:
   #   cpu: 10m