Chart: Make pod affinity templatable. (#11453)

* [helm] template pod affinity

* update README

* Apply suggestions from code review

Co-authored-by: Marco Ebert <marco_ebert@icloud.com>

* revert Chart.yaml version bump

* add unittests

* add docs defaultBackend.affinity

* add README section to values

* fix README syntax

* Apply suggestions from code review

Co-authored-by: Marco Ebert <marco_ebert@icloud.com>

* Update charts/ingress-nginx/values.yaml

Co-authored-by: Marco Ebert <marco_ebert@icloud.com>

* update formatting of unittests + add README examples

* fix affinity labels on default-backend

* Apply suggestions from code review

Co-authored-by: Marco Ebert <marco_ebert@icloud.com>

* remove double quotes on string

---------

Co-authored-by: Marco Ebert <marco_ebert@icloud.com>

charts/ingress-nginx/README.md

@@ -485,7 +485,7 @@ As of version `1.26.0` of this chart, by simply not providing any clusterIP valu
 | controller.udp.configMapNamespace | string | `""` | Allows customization of the udp-services-configmap; defaults to $(POD_NAMESPACE) |
 | controller.updateStrategy | object | `{}` | The update strategy to apply to the Deployment or DaemonSet # |
 | controller.watchIngressWithoutClass | bool | `false` | Process Ingress objects without ingressClass annotation/ingressClassName field Overrides value for --watch-ingress-without-class flag of the controller binary Defaults to false |
-| defaultBackend.affinity | object | `{}` |  |
+| defaultBackend.affinity | object | `{}` | Affinity and anti-affinity rules for server scheduling to nodes # Ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity |
 | defaultBackend.autoscaling.annotations | object | `{}` |  |
 | defaultBackend.autoscaling.enabled | bool | `false` |  |
 | defaultBackend.autoscaling.maxReplicas | int | `2` |  |

charts/ingress-nginx/templates/controller-daemonset.yaml

@@ -203,7 +203,7 @@ spec:
       tolerations: {{ toYaml .Values.controller.tolerations | nindent 8 }}
     {{- end }}
     {{- if .Values.controller.affinity }}
-      affinity: {{ toYaml .Values.controller.affinity | nindent 8 }}
+      affinity: {{ tpl (toYaml .Values.controller.affinity) $ | nindent 8 }}
     {{- end }}
     {{- if .Values.controller.topologySpreadConstraints }}
       topologySpreadConstraints: {{ tpl (toYaml .Values.controller.topologySpreadConstraints) $ | nindent 8 }}

charts/ingress-nginx/templates/controller-deployment.yaml

@@ -206,7 +206,7 @@ spec:
       tolerations: {{ toYaml .Values.controller.tolerations | nindent 8 }}
     {{- end }}
     {{- if .Values.controller.affinity }}
-      affinity: {{ toYaml .Values.controller.affinity | nindent 8 }}
+      affinity: {{ tpl (toYaml .Values.controller.affinity) $ | nindent 8 }}
     {{- end }}
     {{- if .Values.controller.topologySpreadConstraints }}
       topologySpreadConstraints: {{ tpl (toYaml .Values.controller.topologySpreadConstraints) $ | nindent 8 }}

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

@@ -107,7 +107,7 @@ spec:
       tolerations: {{ toYaml .Values.defaultBackend.tolerations | nindent 8 }}
     {{- end }}
     {{- if .Values.defaultBackend.affinity }}
-      affinity: {{ toYaml .Values.defaultBackend.affinity | nindent 8 }}
+      affinity: {{ tpl (toYaml .Values.defaultBackend.affinity) $ | nindent 8 }}
     {{- end }}
     {{- if .Values.defaultBackend.topologySpreadConstraints }}
       topologySpreadConstraints: {{ tpl (toYaml .Values.defaultBackend.topologySpreadConstraints) $ | nindent 8 }}

charts/ingress-nginx/tests/controller-daemonset_test.yaml

@@ -95,3 +95,46 @@ tests:
               topologyKey: kubernetes.io/hostname
               maxSkew: 1
               whenUnsatisfiable: ScheduleAnyway
+
+  - it: should create a DaemonSet with affinity if `controller.affinity` is set
+    set:
+      controller.kind: DaemonSet
+      controller.affinity:
+        podAntiAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            - labelSelector:
+                matchExpressions:
+                  - key: app.kubernetes.io/name
+                    operator: In
+                    values:
+                      - '{{ include "ingress-nginx.name" . }}'
+                  - key: app.kubernetes.io/instance
+                    operator: In
+                    values:
+                      - '{{ .Release.Name }}'
+                  - key: app.kubernetes.io/component
+                    operator: In
+                    values:
+                      - controller
+              topologyKey: kubernetes.io/hostname
+    asserts:
+      - equal:
+          path: spec.template.spec.affinity
+          value:
+            podAntiAffinity:
+              requiredDuringSchedulingIgnoredDuringExecution:
+                - labelSelector:
+                    matchExpressions:
+                      - key: app.kubernetes.io/name
+                        operator: In
+                        values:
+                          - ingress-nginx
+                      - key: app.kubernetes.io/instance
+                        operator: In
+                        values:
+                          - RELEASE-NAME
+                      - key: app.kubernetes.io/component
+                        operator: In
+                        values:
+                          - controller
+                  topologyKey: kubernetes.io/hostname

charts/ingress-nginx/tests/controller-deployment_test.yaml

@@ -118,3 +118,45 @@ tests:
               topologyKey: kubernetes.io/hostname
               maxSkew: 1
               whenUnsatisfiable: ScheduleAnyway
+
+  - it: should create a Deployment with affinity if `controller.affinity` is set
+    set:
+      controller.affinity:
+        podAntiAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            - labelSelector:
+                matchExpressions:
+                  - key: app.kubernetes.io/name
+                    operator: In
+                    values:
+                      - '{{ include "ingress-nginx.name" . }}'
+                  - key: app.kubernetes.io/instance
+                    operator: In
+                    values:
+                      - '{{ .Release.Name }}'
+                  - key: app.kubernetes.io/component
+                    operator: In
+                    values:
+                      - controller
+              topologyKey: kubernetes.io/hostname
+    asserts:
+      - equal:
+          path: spec.template.spec.affinity
+          value:
+            podAntiAffinity:
+              requiredDuringSchedulingIgnoredDuringExecution:
+                - labelSelector:
+                    matchExpressions:
+                      - key: app.kubernetes.io/name
+                        operator: In
+                        values:
+                          - ingress-nginx
+                      - key: app.kubernetes.io/instance
+                        operator: In
+                        values:
+                          - RELEASE-NAME
+                      - key: app.kubernetes.io/component
+                        operator: In
+                        values:
+                          - controller
+                  topologyKey: kubernetes.io/hostname

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

@@ -92,3 +92,46 @@ tests:
               topologyKey: kubernetes.io/hostname
               maxSkew: 1
               whenUnsatisfiable: ScheduleAnyway
+
+  - it: should create a Deployment with affinity if `defaultBackend.affinity` is set
+    set:
+      defaultBackend.enabled: true
+      defaultBackend.affinity:
+        podAntiAffinity:
+          requiredDuringSchedulingIgnoredDuringExecution:
+            - labelSelector:
+                matchExpressions:
+                  - key: app.kubernetes.io/name
+                    operator: In
+                    values:
+                      - '{{ include "ingress-nginx.name" . }}'
+                  - key: app.kubernetes.io/instance
+                    operator: In
+                    values:
+                      - '{{ .Release.Name }}'
+                  - key: app.kubernetes.io/component
+                    operator: In
+                    values:
+                      - default-backend
+              topologyKey: kubernetes.io/hostname
+    asserts:
+      - equal:
+          path: spec.template.spec.affinity
+          value:
+            podAntiAffinity:
+              requiredDuringSchedulingIgnoredDuringExecution:
+                - labelSelector:
+                    matchExpressions:
+                      - key: app.kubernetes.io/name
+                        operator: In
+                        values:
+                          - ingress-nginx
+                      - key: app.kubernetes.io/instance
+                        operator: In
+                        values:
+                          - RELEASE-NAME
+                      - key: app.kubernetes.io/component
+                        operator: In
+                        values:
+                          - default-backend
+                  topologyKey: kubernetes.io/hostname

charts/ingress-nginx/values.yaml

@@ -260,11 +260,11 @@ controller:
   #         - key: app.kubernetes.io/name
   #           operator: In
   #           values:
-  #           - ingress-nginx
+  #           - '{{ include "ingress-nginx.name" . }}'
   #         - key: app.kubernetes.io/instance
   #           operator: In
   #           values:
-  #           - ingress-nginx
+  #           - '{{ .Release.Name }}'
   #         - key: app.kubernetes.io/component
   #           operator: In
   #           values:
@@ -279,16 +279,16 @@ controller:
   #       - key: app.kubernetes.io/name
   #         operator: In
   #         values:
-  #         - ingress-nginx
+  #         - '{{ include "ingress-nginx.name" . }}'
   #       - key: app.kubernetes.io/instance
   #         operator: In
   #         values:
-  #         - ingress-nginx
+  #         - '{{ .Release.Name }}'
   #       - key: app.kubernetes.io/component
   #         operator: In
   #         values:
   #         - controller
-  #     topologyKey: "kubernetes.io/hostname"
+  #     topologyKey: kubernetes.io/hostname
 
   # -- Topology spread constraints rely on node labels to identify the topology domain(s) that each Node is in.
   ## Ref: https://kubernetes.io/docs/concepts/workloads/pods/pod-topology-spread-constraints/
@@ -1011,7 +1011,49 @@ defaultBackend:
   #    value: "value"
   #    effect: "NoSchedule|PreferNoSchedule|NoExecute(1.6 only)"
 
+  # -- Affinity and anti-affinity rules for server scheduling to nodes
+  ## Ref: https://kubernetes.io/docs/concepts/configuration/assign-pod-node/#affinity-and-anti-affinity
   affinity: {}
+  # # An example of preferred pod anti-affinity, weight is in the range 1-100
+  # podAntiAffinity:
+  #   preferredDuringSchedulingIgnoredDuringExecution:
+  #   - weight: 100
+  #     podAffinityTerm:
+  #       labelSelector:
+  #         matchExpressions:
+  #         - key: app.kubernetes.io/name
+  #           operator: In
+  #           values:
+  #           - '{{ include "ingress-nginx.name" . }}'
+  #         - key: app.kubernetes.io/instance
+  #           operator: In
+  #           values:
+  #           - '{{ .Release.Name }}'
+  #         - key: app.kubernetes.io/component
+  #           operator: In
+  #           values:
+  #           - default-backend
+  #       topologyKey: kubernetes.io/hostname
+
+  # # An example of required pod anti-affinity
+  # podAntiAffinity:
+  #   requiredDuringSchedulingIgnoredDuringExecution:
+  #   - labelSelector:
+  #       matchExpressions:
+  #       - key: app.kubernetes.io/name
+  #         operator: In
+  #         values:
+  #         - '{{ include "ingress-nginx.name" . }}'
+  #       - key: app.kubernetes.io/instance
+  #         operator: In
+  #         values:
+  #         - '{{ .Release.Name }}'
+  #       - key: app.kubernetes.io/component
+  #         operator: In
+  #         values:
+  #         - default-backend
+  #     topologyKey: kubernetes.io/hostname
+
   # -- Topology spread constraints rely on node labels to identify the topology domain(s) that each Node is in.
   # Ref.: https://kubernetes.io/docs/concepts/workloads/pods/pod-topology-spread-constraints/
   topologySpreadConstraints: []