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GSLB ResourceRef Support

Starting from v0.15.0, k8gb introduces a much simpler way to link a GSLB resource to an Ingress object in Kubernetes. You no longer need to duplicate the Ingress configuration in your GSLB definition—instead, you can simply reference an existing Ingress. This makes your Ingress the single source of truth for application routing.

K8GB supports the following ingress resources:

1. Declaration by Name

The simplest way is to directly specify the name of the resource you want to reference in your GSLB. The namespace will be automatically taken from the GSLB’s namespace.

Ingress: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
  namespace: playground
spec:
  resourceRef:
    apiVersion: networking.k8s.io/v1
    kind: Ingress
    name: playground-failover-ingress

LoadBalancer Service: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
  namespace: playground
  annotations:
    k8gb.io/hostname: "myapp.example.com"
spec:
  resourceRef:
    apiVersion: v1
    kind: Service
    name: playground-failover-lbservice

Istio Virtual Service: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
  namespace: playground
spec:
  resourceRef:
    apiVersion: networking.istio.io/v1
    kind: VirtualService
    name: playground-failover-virtualservice

GatewayAPI HTTPRoute: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
  namespace: playground
spec:
  resourceRef:
    apiVersion: gateway.networking.k8s.io/v1
    kind: HTTPRoute
    name: playground-failover-httproute

GatewayAPI GRPCRoute: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
  namespace: playground
spec:
  resourceRef:
    apiVersion: gateway.networking.k8s.io/v1
    kind: GRPCRoute
    name: playground-failover-grpcroute

GatewayAPI TCPRoute: 

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: failover-tcproute
  namespace: playground
  annotations:
    k8gb.io/hostname: gatewayapi-tcproute.cloud.example.com
spec:
  resourceRef:
    apiVersion: gateway.networking.k8s.io/v1alpha2
    kind: TCPRoute
    name: failover-tcproute

2. Declaration by Label

Alternatively, you can reference the ingress resource by label. This approach is useful when you need more flexibility—for example, in CI/CD pipelines. It is required that only one resource in the namespace matches the label; otherwise, k8gb will return an error.

Here we show only an example for Ingress resources, but the same applies for Istio and GatewayAPI integrations.

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: playground-failover
spec:
  resourceRef:
    apiVersion: networking.k8s.io/v1
    kind: Ingress
    matchLabels:
      app: playground-failover

3. Embedded Declaration (Legacy)

For backward compatibility, you can still use the original way where the Ingress configuration is embedded directly inside the GSLB resource. This method will continue to work, but we recommend switching to reference-based configuration for simpler management and to avoid configuration drift.

apiVersion: k8gb.absa.oss/v1beta1
kind: Gslb
metadata:
  name: failover-playground-embedded
spec:
  ingress:
    ingressClassName: nginx
    rules:
      - host: failover-playground-embedded.cloud.example.com
        http:
          paths:
          - path: /
            pathType: Prefix
            backend:
              service:
                name: frontend-podinfo
                port:
                  name: http
  strategy:
    type: failover
    dnsTtlSeconds: 5
    primaryGeoTag: "eu"

Note: If the Ingress is created automatically by a GSLB resource, in addition to an ownerReference, it will also be marked with the label: app.k8gb.io/managed-by: gslb. This makes it easy to identify Ingresses managed by k8gb.