Split TCP traffic between multi-port services

This page describes the process for splitting TCP, HTTP, and gRPC traffic between two ports of a multi-port service. It includes an example TCPRoute resource configuration to demonstrate Consul's multi-port features.

Prerequisites

Splitting traffic between two ports of a multi-port service requires the v2 catalog API.

In addition, they are two different workflows for registering Services in Kubernetes using the v2 catalog API. The instructions on this page offer examples for two configuration methods:

• Method 1: Register a Kubernetes service that select workloads which expose multiple ports
• Method 2: Register multiple Kubernetes Services that direct traffic to an explicit port on the same workload

For guidance on enabling the v2 catalog, deploying multi-port services using these methods, and applying traffic permissions to the services, refer to configure multi-port services.

Overview

Complete the following steps to implement a split in TCP traffic between two services:

1. Define the resource's behavior in a custom resource definition (CRD).
2. Apply the resource to your cluster.

Define route resource

The following example splits traffic for the api service. TCP traffic for services registered to the Consul catalog that are available at the api-workload port is split so that 50% of the traffic routes to the service at the api-workload port and 50% routes to the service at the admin-workload port.

apiVersion: mesh.consul.hashicorp.com/v2beta1
kind: TCPRoute
metadata:
  name: api-split
spec:
  parentRefs:
    - ref:
        type:
          group: catalog
          groupVersion: v2beta1
          kind: Service
        name: api
      # The virtual port number for the "api-workload" target port.
      port: "80"
  rules:
    - backendRefs:
      - backendRef:
          ref:
            type:
              group: catalog
              groupVersion: v2beta1
              kind: Service
            name: api
          # The virtual port number for the "api-workload" target port.
          port: "80"
        weight: 50
      - backendRef:
          ref:
            type:
              group: catalog
              groupVersion: v2beta1
              kind: Service
            name: api
          # The virtual port number for the "admin-workload" target port.
          port: "90"
        weight: 50

Apply the resource

Use the kubectl command to apply the resource to your Consul cluster.

$ kubectl apply -f api-split.yaml

$ kubectl exec -it ${WEB_POD} -c web -- curl api:90

$ kubectl exec -it ${WEB_POD} -c web -- curl api-admin:90

Half of the traffic should respond with the hello world response from port 80, instead of port 90's response of hello world from 9090 admin. Repeat the command several times to verify that you receive both responses.