Use TCPRoute

The Gateway API defines specialized resources for routing different types of network traffic. You would use a TCPRoute resource to route TCP traffic.

To add routing for TCP traffic:

1. Deploy a Gateway object that includes TCPRoute in its allowedRoutes.kinds section. This advertises that this Gateway, and by extension the ingress controller, watches for routes of this kind.

   default-namespace-gateway.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: Gateway
   metadata:
     name: default-namespace-gateway
     namespace: default
   spec:
     gatewayClassName: haproxy-ingress-gatewayclass
     listeners:
       - allowedRoutes:
           kinds:
             - group: gateway.networking.k8s.io
               kind: TCPRoute
           namespaces:
             from: Same
         name: listener1
         port: 8000
         protocol: TCP

   default-namespace-gateway.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: Gateway
   metadata:
     name: default-namespace-gateway
     namespace: default
   spec:
     gatewayClassName: haproxy-ingress-gatewayclass
     listeners:
       - allowedRoutes:
           kinds:
             - group: gateway.networking.k8s.io
               kind: TCPRoute
           namespaces:
             from: Same
         name: listener1
         port: 8000
         protocol: TCP

   Apply the changes with kubectl:

   nix
   kubectl apply -f default-namespace-gateway.yaml

   nix
   kubectl apply -f default-namespace-gateway.yaml

2. Optional: If you will be creating TCPRoute objects that are in a namespace different from the namespace of the target service, you must define a ReferenceGrant object that allows cross-namespace communication.

   Below, the ReferenceGrant allows a route in the default namespace to reference a service in the foo namespace. Note that the to section does not need a namespace because a ReferenceGrant can refer only to resources defined in its own namespace.

   foo-referencegrant.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: ReferenceGrant
   metadata:
     name: refgrantns1
     namespace: foo
   spec:
     from:
       - group: "gateway.networking.k8s.io"
         kind: "TCPRoute"
         namespace: default
     to:
       - group: ""
         kind: "Service"

   foo-referencegrant.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: ReferenceGrant
   metadata:
     name: refgrantns1
     namespace: foo
   spec:
     from:
       - group: "gateway.networking.k8s.io"
         kind: "TCPRoute"
         namespace: default
     to:
       - group: ""
         kind: "Service"

   Apply the changes with kubectl:

   nix
   kubectl apply -f foo-referencegrant.yaml

   nix
   kubectl apply -f foo-referencegrant.yaml

3. Define a TCPRoute resource to route TCP traffic to a Kubernetes service.

   example-route.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: TCPRoute
   metadata:
     name: example-route
     namespace: default
   spec:
     parentRefs:
       - group: gateway.networking.k8s.io
         kind: Gateway
         name: default-namespace-gateway
         namespace: default
     rules:
       - backendRefs:
           - group: ''
             kind: Service
             name: example-service
             port: 80
             weight: 10

   example-route.yaml
   yaml
   apiVersion: gateway.networking.k8s.io/v1alpha2
   kind: TCPRoute
   metadata:
     name: example-route
     namespace: default
   spec:
     parentRefs:
       - group: gateway.networking.k8s.io
         kind: Gateway
         name: default-namespace-gateway
         namespace: default
     rules:
       - backendRefs:
           - group: ''
             kind: Service
             name: example-service
             port: 80
             weight: 10

   From this snippet:

   • The parentRefs section references the gateways to which a route wants to attach. This TCPRoute will attach to listeners defined in the Gateway whose allowedRoutes have matching kind and namespace rules.
   • The backendRefs section refers to services where connections should be sent. Each item’s port attribute is the service’s listening port. The weight attribute sets the proportion of connections that should go to the service, which is calculated by weight/(sum of all weights in this backendRefs list).

   Apply the changes with kubectl:

   nix
   kubectl apply -f example-route.yaml

   nix
   kubectl apply -f example-route.yaml