cmd/k8s-operator: Allow custom ingress class names (#16472)

This commit modifies the k8s operator to allow for customisation of the ingress class name
via a new `OPERATOR_INGRESS_CLASS_NAME` environment variable. For backwards compatibility,
this defaults to `tailscale`.

When using helm, a new `ingress.name` value is provided that will set this environment variable
and modify the name of the deployed `IngressClass` resource.

Fixes https://github.com/tailscale/tailscale/issues/16248

Signed-off-by: David Bond <davidsbond93@gmail.com>

cmd/k8s-operator/deploy/chart/templates/deployment.yaml

@@ -70,6 +70,8 @@ spec:
                   fieldPath: metadata.namespace
             - name: OPERATOR_LOGIN_SERVER
               value: {{ .Values.loginServer }}
+            - name: OPERATOR_INGRESS_CLASS_NAME
+              value: {{ .Values.ingressClass.name }}
             - name: CLIENT_ID_FILE
               value: /oauth/client_id
             - name: CLIENT_SECRET_FILE

cmd/k8s-operator/deploy/chart/templates/ingressclass.yaml

@@ -2,7 +2,7 @@
 apiVersion: networking.k8s.io/v1
 kind: IngressClass
 metadata:
-  name: tailscale # class name currently can not be changed
+  name: {{ .Values.ingressClass.name }}
   annotations: {} # we do not support default IngressClass annotation https://kubernetes.io/docs/concepts/services-networking/ingress/#default-ingress-class
 spec:
   controller: tailscale.com/ts-ingress # controller name currently can not be changed

cmd/k8s-operator/deploy/chart/values.yaml

@@ -77,6 +77,10 @@ operatorConfig:
 
 # In the case that you already have a tailscale ingressclass in your cluster (or vcluster), you can disable the creation here
 ingressClass:
+  # Allows for customization of the ingress class name used by the operator to identify ingresses to reconcile. This does
+  # not allow multiple operator instances to manage different ingresses, but provides an onboarding route for users that
+  # may have previously set up ingress classes named "tailscale" prior to using the operator.
+  name: "tailscale"
   enabled: true
 
 # proxyConfig contains configuraton that will be applied to any ingress/egress