KSQLDB connection refused to Kafka Connect - apache-kafka

Question

I am doing PoC on KSQLDB Elasticsearch connector.
I am following from 2 documents online:
One:
https://ksqldb.io/quickstart.html
All working fine and well and after I fallowed
Second one:
https://github.com/confluentinc/demo-scene/blob/master/build-a-streaming-pipeline/demo_build-a-streaming-pipeline.adoc
I am getting this issue when I run this command:
CREATE SINK CONNECTOR SINK_ES_sample_1 WITH (
'connector.class' = 'io.confluent.connect.elasticsearch.ElasticsearchSinkConnector',
'topics' = 'sample_1',
'connection.url' = 'http://localhost:9200',
'type.name' = '_doc',
'key.ignore' = 'false',
'schema.ignore' = 'true',
'transforms'= 'ExtractTimestamp',
'transforms.ExtractTimestamp.type'= 'org.apache.kafka.connect.transforms.InsertField$Value',
'transforms.ExtractTimestamp.timestamp.field' = 'sample_1'
);
Error:
io.confluent.ksql.util.KsqlServerException:
org.apache.hc.client5.http.HttpHostConnectException: Connect to
http://localhost:8083 [localhost/127.0.0.1] failed: Connection refused
(Connection refused) Caused by:
org.apache.hc.client5.http.HttpHostConnectException: Connect to
http://localhost:8083 [localhost/127.0.0.1] failed: Connection
refused (Connection refused) Caused by: Could not connect to the
server. Please check the server details are correct and that the
server is running.

Answer 1

That suggests that you've misconfigured the ksqlDB server in its connection to Kafka Connect.
If you're following that demo script then you should use the associated Docker Compose file which is configured correctly:
KSQL_KSQL_CONNECT_URL: http://kafka-connect-01:8083