Accessing kafka from spring boot application running on kubernetes

The bootstrap-servers property expects a list of Kafka server addresses. By putting quotation marks around the value you signaled that the value is a string and therefore create a type conflict.

To solve this issue you should either remove the quotation marks or put the value explicitly in a list form. e.g:

spring:  kafka:    consumer:      bootstrap-servers: ["bootstrap.kafka.svc.cluster.local:9092"]

Sometimes, it will actually be your Kafka Kubernetes deployment that is at fault.

Can I see your deployment YAML/JSON file for the Kafka deployment, please?

It should look like this:

apiVersion: apps/v1kind: Deploymentmetadata:  name: api-kafkaspec:  replicas: 1  selector:    matchLabels:      app: kafka      id: "0"  template:    metadata:      labels:        app: kafka        id: "0"    spec:      containers:        - name: kafka          image: wurstmeister/kafka:latest          ports:            - containerPort: 30035          env:            - name: KAFKA_ADVERTISED_HOST_NAME              valueFrom:                fieldRef:                  fieldPath: status.podIP            - name: KAFKA_ADVERTISED_PORT              value: "9092"            - name: KAFKA_HEAP_OPTS              value: -Xms320m            - name: KAFKA_ZOOKEEPER_CONNECT              value: "zookeeper:2181"---apiVersion: v1kind: Servicemetadata:  name: api-kafka  namespace: default  labels:    name: kafkaspec:  ports:    - port: 9092      name: kafka-port      protocol: TCP  selector:    app: kafka    id: "0"  type: NodePort

With an emphasis on the:

- name: KAFKA_ADVERTISED_HOST_NAME  valueFrom:      fieldRef:          fieldPath: status.podIP

Make sure your profiles are right and that'll fix all of your problems to do with the connections and the advertised hostnames within a Kubernetes Deployment