Debezium Connector for SQL Server - connection refused - sql-server

Question

I want to use Kafka to publish MSSQL CDC events.
I am using Docker containers for:
debezium/zookeeper
debezium/kafka
debezium/connect
Microsoft SQL Server
Containers started as follows:
docker run -it --name zookeeper -p 2181:2181 -p 2888:2888 -p 3888:3888 debezium/zookeeper
docker run -it --name kafka -p 9092:9092 --link zookeeper:zookeeper debezium/kafka
docker run -it --name connect -p 8083:8083 -e GROUP_ID=1 -e CONFIG_STORAGE_TOPIC=my-connect-configs -e OFFSET_STORAGE_TOPIC=my-connect-offsets -e ADVERTISED_HOST_NAME="localhost" --link zookeeper:zookeeper --link kafka:kafka debezium/connect
docker run -e "ACCEPT_EULA=Y" -e "SA_PASSWORD=xxxxxxxxxxxxx" -p 1433:1433 --name sql1 -d mcr.microsoft.com/mssql/server:2017-CU8-ubuntu
All containers start running successfully.
Then I created new MSSQL db in SQL Server container. Created 1 table in new db and turned on CDC for that table. CDC is working fine.
Then I send connector configuration below to Kafka Connect REST API as follows:
curl -X POST -H "Content-Type: application/json" -d #test-mssql-connector.json http://localhost:8083/connectors
using test-mssql-connector.json
{
"name": "test-mssql-connector5",
"config": {
"connector.class": "io.debezium.connector.sqlserver.SqlServerConnector",
"database.hostname": "localhost",
"database.port": "1433",
"database.user": "SA",
"database.password": "xxxxxxxxxxxxx",
"database.dbname": "test",
"database.server.name": "sql1",
"table.whitelist": "dbo.Persons",
"database.history.kafka.bootstrap.servers": "kafka:9092",
"database.history.kafka.topic": "dbhistory.sql1"
}
}
However, Kafka connector cannot connect to the MSSQL db giving error message below:
com.microsoft.sqlserver.jdbc.SQLServerException: The TCP/IP connection
to the host localhost, port 1433 has failed. Error: \"Connection
refused. Verify the connection properties. Make sure that an instance
of SQL Server is running on the host and accepting TCP/IP connections
at the port. Make sure that TCP connections to the port are not
blocked by a firewall.
Most troubleshooting are if database actually running, or port is blocked, but there is no problem with new MSSQL db. It's container is active, and the db is successfully running. The port is not blocked. I can successfully connect to it from host machine using DbVisualizer or other query tools with following configuration:
database server = localhost
database port = 1433
user = SA
pw = xxxxxxxxxxxxx
database name = test
I can successfully use telnet localhost 1433 to connect to server.
Is there something missing in the connector configuration above?

Answer 1

IMHO the localhost is not correct as localhost is something else in Connect container and in SQL Server container. You should link the database container into Connect container and use the appropriate hostname.

Answer 2

You need to first set up your sql container and THEN only start the connect service specifying the sql server as an additional link:
docker run -it --name connect -p 8083:8083 -e GROUP_ID=1 -e CONFIG_STORAGE_TOPIC=my-connect-configs -e OFFSET_STORAGE_TOPIC=my-connect-offsets -e ADVERTISED_HOST_NAME="localhost" --link zookeeper:zookeeper --link kafka:kafka --link kafka:kafka debezium/connect