Kafka consumer not picking mentioned Bootstrap servers - spring-boot

Question

I am trying to implement Kafka consumer with SSL, provide all the required configurations in the application.yml;
When I start the spring boot Kafka consumer application; Consumer is trying to connect the localhost:9092 instead of mentioned Kafka Brokers.
KafkaConfig.java
#Bean
public ConsumerFactory<String, AvroRecord> consumerFactory() throws IOException {
return new DefaultKafkaConsumerFactory<>(kafkaProps());
}
#Bean
public KafkaListenerContainerFactory<ConcurrentMessageListenerContainer<String, AvroRecord>>
kafkaListenerContainerFactory() throws IOException {
ConcurrentKafkaListenerContainerFactory<String, AvroRecord> factory =
new ConcurrentKafkaListenerContainerFactory<>();
factory.setConsumerFactory(consumerFactory());
return factory;
}
kafkaProps() is loading all the SSL and bootstrap servers related properties. Values, I can see it in the debug mode.
application.yml
kafka:
properties:
basic:
auth:
credentials:
source: USER_INFO
user: username
pass: password
enableAutoRegister: true
max_count: 100
max_delay: 5000
schema:
registry:
url: https://schema-registry:8081
ssl:
truststore:
location: <<location>>
password: pwd
keystore:
location: <<location>>
password: pwd
key:
password: pwd
ssl:
enabled: true
protocols: TLSv1.2,TLSv1.1,TLSv1
truststore:
type: JKS
location: <<location>>
password: pwd
keystore:
type: JKS
location: <<location>>
password: pwd
key:
password: pwd
security:
protocol: SSL
consumer:
bootstrap-servers: broker1:9092,broker2:9092
auto-offset-reset: earliest
key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
value-deserializer: io.confluent.kafka.serializers.KafkaAvroDeserializer
max-message-size: 10241024
In the application logs, I am getting the below log
18:46:33.964 [main] INFO o.a.k.c.a.AdminClientConfig requestId=
transactionKey= | AdminClientConfig values:
bootstrap.servers = [localhost:9092]
client.dns.lookup = use_all_dns_ips
client.id =
connections.max.idle.ms = 300000
15:53:54.608 [kafka-admin-client-thread | adminclient-1] WARN o.a.k.c.NetworkClient requestId=
transactionKey= | [AdminClient clientId=adminclient-1] Connection to node -1 (localhost/127.0.0.1:9092) could not be established. Broker may not be available.
I am not able to find it, why it is connecting to localhost instead of mentioned brokers

Answer 1

The correct property is spring.kafka.bootstrap-servers. You appear to be missing the spring prefix completely. Also, schema.registry.url, ssl.truststore, etc are all considered singular property keys (strings) to Kafka clients, so (to my knowledge) therefore should not be "nested" in YAML objects
You only tried to set the bootstrap property on the consumer, not the AdminClient
Your client will always connect to advertised.listeners of the broker after making the initial connection to the bootstrap server string, so if that is localhost:9092, would explain the AdminClient log output