hudi/hudi-kafka-connect/README.md

Quick Start (demo) guide for Kafka Connect Sink for Hudi

This repo contains a sample project that can be used to start off your own source connector for Kafka Connect.

Building the Hudi Sink Connector

The first thing you need to do to start using this connector is building it. In order to do that, you need to install the following dependencies:

• Java 1.8+
• Apache Maven
• Install kcat

After installing these dependencies, execute the following commands. This will install all the Hudi dependency jars, including the fat packaged jar that contains all the dependencies required for a functional Hudi Kafka Connect Sink.

cd $HUDI_DIR
mvn clean -DskipTests install

Henceforth, incremental builds can be performed as follows.

mvn clean -pl hudi-kafka-connect install -DskipTests
mvn clean -pl packaging/hudi-kafka-connect-bundle install

Next, we need to make sure that the hudi sink connector bundle jar is in Kafka Connect classpath. Note that the connect classpath should be same as the one configured in the connector configuration file.

cp $HUDI_DIR/packaging/hudi-kafka-connect-bundle/target/hudi-kafka-connect-bundle-0.10.0-SNAPSHOT.jar /usr/local/share/java/hudi-kafka-connect/

Trying the connector

After building the package, we need to install the Apache Kafka

1 - Starting the environment

To try out the Connect Sink locally, set up a Kafka broker locally. Download the latest apache kafka from https://kafka.apache.org/downloads. Once downloaded and built, run the Zookeeper server and Kafka server using the command line tools.

export KAFKA_HOME=/path/to/kafka_install_dir
cd $KAFKA_KAFKA_HOME
./bin/zookeeper-server-start.sh ./config/zookeeper.properties
./bin/kafka-server-start.sh ./config/server.properties

Wait until the kafka cluster is up and running.

2 - Set up the schema registry

Hudi leverages schema registry to obtain the latest schema when writing records. While it supports most popular schema registries, we use Confluent schema registry. Download the latest confluent schema registry code from https://github.com/confluentinc/schema-registry and start the schema registry service.

cd $CONFLUENT_DIR
./bin/schema-registry-start etc/schema-registry/schema-registry.properties

3 - Create the Hudi Control Topic for Coordination of the transactions

The control topic should only have 1 partition, since its used to coordinate the Hudi write transactions across the multiple Connect tasks.

cd $KAFKA_HOME
./bin/kafka-topics.sh --delete --topic hudi-control-topic --bootstrap-server localhost:9092
./bin/kafka-topics.sh --create --topic hudi-control-topic --partitions 1 --replication-factor 1 --bootstrap-server localhost:9092

4 - Create the Hudi Topic for the Sink and insert data into the topic

Open a terminal to execute the following command:

cd $HUDI_DIR/demo/
bash setupKafka.sh -n <total_kafka_messages>

4 - Run the Sink connector worker (multiple workers can be run)

The Kafka connect is a distributed platform, with the ability to run one or more workers (each running multiple tasks) that parallely process the records from the Kafka partitions for the same topic. We provide a properties file with default properties to start a Hudi connector.

Note that if multiple workers need to be run, the webserver needs to be reconfigured for subsequent workers to ensure successful running of the workers.

cd $KAFKA_HOME
./bin/connect-distributed.sh $HUDI_DIR/hudi-kafka-connect/demo/connect-distributed.properties

5- To add the Hudi Sink to the Connector (delete it if you want to re-configure)

Once the Connector has started, it will not run the Sink, until the Hudi sink is added using the web api. The following curl APIs can be used to delete and add a new Hudi Sink. Again, a default configuration is provided for the Hudi Sink, that can be changed based on the desired properties.

curl -X DELETE http://localhost:8083/connectors/hudi-sink
curl -X POST -H "Content-Type:application/json" -d @$HUDI-DIR/hudi-kafka-connect/demo/config-sink.json http://localhost:8083/connectors

Now, you should see that the connector is created and tasks are running.

curl -X GET -H "Content-Type:application/json"  http://localhost:8083/connectors
["hudi-sink"]
curl -X GET -H "Content-Type:application/json"  http://localhost:8083/connectors/hudi-sink/status | jq