feat(helm): allow skipping IngressClass creation (#3979)

Signed-off-by: EndlessSeeker <1766508902@qq.com>

helm/core/templates/ingressclass.yaml

@@ -1,8 +1,8 @@
-{{- if .Values.global.ingressClass }}
-apiVersion: networking.k8s.io/v1
-kind: IngressClass
-metadata:
-  name: {{ .Values.global.ingressClass }}
-spec:
-  controller: higress.io/higress-controller
-{{- end }}
+{{- if and .Values.global.ingressClass .Values.global.createIngressClass }}
+apiVersion: networking.k8s.io/v1
+kind: IngressClass
+metadata:
+  name: {{ .Values.global.ingressClass }}
+spec:
+  controller: higress.io/higress-controller
+{{- end }}

helm/core/values.yaml

@@ -25,6 +25,9 @@ global:
   # 2. When the ingress class is set empty, the higress controller will watch all ingress
   # resources in the k8s cluster.
   ingressClass: "higress"
+  # -- Whether to create the IngressClass resource for global.ingressClass.
+  # Set this to false when reusing an existing IngressClass, for example during Nginx Ingress migration.
+  createIngressClass: true
   # -- If not empty, Higress Controller will only watch resources in the specified namespace.
   # When isolating different business systems using K8s namespace,
   # if each namespace requires a standalone gateway instance,