How to Push Messages with Alibaba Cloud Kafka in Knative: A Step‑by‑Step Guide

Background

Knative now supports Kafka event sources. This guide shows how to use Alibaba Cloud Message Queue for Apache Kafka to push messages into Knative services.

Create a Kafka instance on Alibaba Cloud

Log in to the Message Queue for Apache Kafka console, purchase a professional version (annual/monthly) that supports version 2.0.0 or later, then deploy the instance and bind it to the VPC where the Knative cluster resides.

Create Topic and Consumer Group

In the console, go to Topic Management and create a topic named demo. Then go to Consumer Group Management and create a consumer group named demo-consumer.

Deploy the Kafka addon component

In the Container Service console, open Knative Component Management and deploy the Kafka addon.

Create a Knative Service to receive events

Define a Knative Service named event-display that runs the sample event‑display container image.

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: event-display
spec:
  template:
    spec:
      containers:
      - image: registry.cn-hangzhou.aliyuncs.com/knative-sample/eventing-sources-cmd-event_display:bf45b3eb1e7fc4cb63d6a5a6416cf696295484a7662e0cf9ccdf5c080542c21d

Create the KafkaSource

Apply a KafkaSource that points to the previously created topic and consumer group, and routes events to the event-display service.

apiVersion: sources.eventing.knative.dev/v1alpha1
kind: KafkaSource
metadata:
  name: alikafka-source
spec:
  consumerGroup: demo-consumer
  bootstrapServers: 192.168.0.6x:9092,192.168.0.7x:9092,192.168.0.8x:9092
  topics: demo
  sink:
    apiVersion: serving.knative.dev/v1alpha1
    kind: Service
    name: event-display

bootstrapServers

: VPC‑accessible Kafka broker addresses consumerGroup: name of the consumer group topics: topic to subscribe

Verify the setup

Send a JSON message to the demo topic via the Kafka console. The event‑display service receives the CloudEvent and logs show the payload.

# kubectl logs event-display-... user-container
☁️  CloudEvent: valid ✅
Context Attributes,
  SpecVersion: 0.2
  Type: dev.knative.kafka.event
  Source: /apis/v1/namespaces/default/kafkasources/alikafka-source#demo
  ID: partition:7/offset:1
  Time: 2019-10-18T08:50:32.492Z
  ContentType: application/json
  Extensions:
    key: demo
Data,
  {"key":"test"}

Conclusion

By combining Alibaba Cloud Kafka with Knative Eventing, you can trigger serverless services with high‑throughput, low‑latency messages in a simple, cloud‑native way.