helm: Add support to define nodeSelector for the NGINX Gateway Fabric pod. (nginx#1531)

Problem: The current helm chart doesn't support the nodeSelector definition for the NGINX Gateway Fabric pod.

Solution: Add support for nodeSelector in the helm chart.

Author: miledxz

deploy/helm-chart/README.md

@@ -301,6 +301,7 @@ The following tables lists the configurable parameters of the NGINX Gateway Fabr
 | `nginx.extraVolumeMounts`                         | Extra `volumeMounts` for the nginx container.                                                                                                                                                            | {}                                                                                                              |
 | `terminationGracePeriodSeconds`                   | The termination grace period of the NGINX Gateway Fabric pod.                                                                                                                                            | 30                                                                                                              |
 | `tolerations`                                     | The `tolerations` of the NGINX Gateway Fabric pod.                                                                                                                                                       | []                                                                                                              |
+| `nodeSelector`                                    | The `nodeSelector` of the NGINX Gateway Fabric pod.                                                                                                                                                       | {}                                                                                                              |
 | `affinity`                                        | The `affinity` of the NGINX Gateway Fabric pod.                                                                                                                                                          | {}                                                                                                              |
 | `serviceAccount.annotations`                      | The `annotations` for the ServiceAccount used by the NGINX Gateway Fabric deployment.                                                                                                                    | {}                                                                                                              |
 | `serviceAccount.name`                             | Name of the ServiceAccount used by the NGINX Gateway Fabric deployment.                                                                                                                                  | Autogenerated                                                                                                   |

deploy/helm-chart/templates/deployment.yaml

@@ -156,6 +156,10 @@ spec:
       tolerations:
       {{- toYaml .Values.tolerations | nindent 6 }}
       {{- end }}
+      {{- if .Values.nodeSelector }}
+      nodeSelector:
+      {{- toYaml .Values.nodeSelector | nindent 8 }}
+      {{- end }}
       volumes:
       - name: nginx-conf
         emptyDir: {}

deploy/helm-chart/values.yaml

@@ -73,6 +73,9 @@ terminationGracePeriodSeconds: 30
 ## Tolerations for the NGINX Gateway Fabric pod.
 tolerations: []
 
+##  The nodeSelector of the NGINX Gateway Fabric pod.
+nodeSelector: {}
+
 ## The affinity of the NGINX Gateway Fabric pod.
 affinity: {}