Configure a TCP Layer-4 Route

Prerequisites

Higress is installed in the higress-system namespace in K8s, with the gateway’s Service name being higress-gateway;
The goal is to configure a layer-4 route for the tcp-echo service in the default namespace, with the service listening on port 9000 and the gateway also listening on port 9000;
The route is configured using Gateway API CRD, which requires Higress to be configured to support Gateway API in advance. Reference documentation: Document

Configuration Steps

1. Create GatewayClass

Create a gatewayclass.yaml file with the following content:

apiVersion: gateway.networking.k8s.io/v1
kind: GatewayClass
metadata:
  name: higress-gateway
spec:
  controllerName: "higress.io/gateway-controller"

Execute the command to apply the configuration to the K8s cluster:
Terminal window
```
kubectl apply -f gatewayclass.yaml
```

2. Create Gateway

Create a gateway.yaml file with the following content:

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: higress-gateway
  namespace: higress-system
spec:
  gatewayClassName: higress-gateway
  listeners:
  - name: default-tcp
    protocol: TCP
    port: 9000
    allowedRoutes:
      namespaces:
        from: All
      kinds:
      - kind: TCPRoute

Execute the command to apply the configuration to the K8s cluster:
Terminal window
```
kubectl apply -f gateway.yaml
```

3. Modify the `higress-gateway` Service

Execute the command to enter the edit state of the higress-gateway Service:
Terminal window
```
kubectl edit service higress-gateway -n higress-system
```

Add a description for port 9000 to the spec.ports list. The configuration after the addition should look like this:

...
  ports:
  - name: http2
    port: 80
    protocol: TCP
    targetPort: 80
  - name: https
    port: 443
    protocol: TCP
    targetPort: 443
  # --- Configuration added here ---
  - name: tcp
    port: 9000
    protocol: TCP
    targetPort: 9000
  # -----------------------------
...

Save the edits and exit the editor.

4. Create TCPRoute

Create a tcproute.yaml file with the following content:

apiVersion: gateway.networking.k8s.io/v1alpha2
kind: TCPRoute
metadata:
  name: tcp-echo
  namespace: default
spec:
  parentRefs:
  - name: higress-gateway
    namespace: higress-system
    port: 9000
  rules:
  - backendRefs:
    - name: tcp-echo
      port: 9000

Execute the command to apply the configuration to the K8s cluster:
Terminal window
```
kubectl apply -f tcproute.yaml
```

5. Configuration Verification

Configuration complete. We can verify whether the route is working properly by using telnet to connect to port 9000 of the higress-gateway service or by other means.