Strimzi - Connecting external clients

Question

Following on discussion here, I used the following steps to enable an external client (based on kafkajs) connect to Strimzi on OpenShift. These steps are from here.

Enable external route

The kafka-persistent-single.yaml is edited to as shown below.

apiVersion: kafka.strimzi.io/v1beta1
kind: Kafka
metadata:
  name: my-cluster
spec:
  kafka:
    version: 2.3.0
    replicas: 1
    listeners:
      plain: {}
      tls: {}
      external:
          type: route
    config:
      offsets.topic.replication.factor: 1
      transaction.state.log.replication.factor: 1
      transaction.state.log.min.isr: 1
      log.message.format.version: "2.3"
    storage:
      type: jbod
      volumes:
      - id: 0
        type: persistent-claim
        size: 5Gi
        deleteClaim: false
  zookeeper:
    replicas: 1
    storage:
      type: persistent-claim
      size: 5Gi
      deleteClaim: false
  entityOperator:
    topicOperator: {}
    userOperator: {}

Extract certificate,

To extract certificate and use it in client, I ran the following command:

kubectl get secret my-cluster-cluster-ca-cert -o jsonpath='{.data.ca\.crt}' | base64 -D > ca.crt

Note that, I had to use base64 -D on my macOS and not base64 -d as shown in documentation.

Kafkajs client

This is the client adapted from their npm page and their documentation.

const fs = require('fs')
const { Kafka } = require('kafkajs')

const kafka = new Kafka({
  clientId: 'my-app',
  brokers: ['my-cluster-kafka-bootstrap-messaging-os.192.168.99.100.nip.io'],
  ssl : { rejectUnauthorized: false,
    ca : [fs.readFileSync('ca.crt', 'utf-8')]
  }
})

const producer = kafka.producer()
const consumer = kafka.consumer({ groupId: 'test-group' })

const run = async () => {
  // Producing
  await producer.connect()
  await producer.send({
    topic: 'test-topic',
    messages: [
      { value: 'Hello KafkaJS user!' },
    ],
  })

  // Consuming
  await consumer.connect()
  await consumer.subscribe({ topic: 'test-topic', fromBeginning: true })

  await consumer.run({
    eachMessage: async ({ topic, partition, message }) => {
      console.log({
        partition,
        offset: message.offset,
        value: message.value.toString(),
      })
    },
  })
}

run().catch(console.error)

Question

When I run node sample.js from the folder having ca.crt, I get a connection refused message.

{"level":"ERROR","timestamp":"2019-10-05T03:22:40.491Z","logger":"kafkajs","message":"[Connection] Connection error: connect ECONNREFUSED 192.168.99.100:9094","broker":"my-cluster-kafka-bootstrap-messaging-os.192.168.99.100.nip.io:9094","clientId":"my-app","stack":"Error: connect ECONNREFUSED 192.168.99.100:9094\n    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1113:14)"}

What am I missing?

ppatierno ppatierno · Accepted Answer · 2019-10-05T05:16:02

I guess that the problem is that you are missing the right port 443 on the broker address so you have to use

brokers: ['my-cluster-kafka-bootstrap-messaging-os.192.168.99.100.nip.io:443']

otherwise it is trying to connect to the default port 80 on the OpenShift route.