clickhouse-sink-connector/doc/setup.md

This doc describes how to set up CDC pipeline

Pipeline

Setup local pipeline

Pre-requisites

• Java JDK 11 (https://openjdk.java.net/projects/jdk/11/)
• Maven (mvn) (https://maven.apache.org/download.cgi)
• Docker and Docker-compose

Sink connector image needs to be built locally. Use the following script to build the image docker/package-build-sink-on-debezium-base.sh docker/package-build-sink-on-debezium-base.sh Future: Github releases will push docker images to Docker hub.

docker-compose

Full pipeline can be launched via docker-compose with the help of docker-compose.yaml It will start:

1. MySQL
2. Zookeeper
3. Debezium MySQL connector
4. RedPanda
5. clickhouse-kafka-sink-connector
6. Clickhouse
7. Confluent Schema registry or Apicurio Schema registry

The start-docker-compose.sh by default uses the latest tag, you could also pass the docker tag to the script. Altinity sink images are tagged on every successful build with the following format(yyyy-mm-dd) Example(2022-07-19)

MySQL:

cd deploy/docker
./start-docker-compose.sh 

Postgres:

cd deploy/docker
docker-compose -f docker-compose.yaml -f docker-compose-postgresql.override.yaml up

Start Docker-compose with a specific docker tag

cd deploy/docker
./start-docker-compose.sh 2022-07-19

Load Airline data set

docker-compose -f docker-compose.yaml -f docker-compose-airline-data.override.yaml up

Stop Docker-compose

cd deploy/docker
./stop-docker-compose.sh

Source connector

After all the docker containers are up and running, execute the following command to create the Debezium MySQL connector.

Make sure MySQL master/slave is up and running before executing the following script.\

MySQL:

    ../deploy/debezium-connector-setup-schema-registry.sh

debezium-connector-setup-schema-registry.sh

Postgres(Using Apicurio):

../deploy/debezium-connector-setup-schema-registry.sh postgres apicurio

Sink Connector

After the source connector is created, execute the script sink-connector-setup-schema-registry.sh to create the Clickhouse Sink connector using Kafka connect REST API

MySQL:

    ../deploy/sink-connector-setup-schema-registry.sh

Postgres(Using Apicurio):

../deploy/sink-connector-setup-schema-registry.sh postgres apicurio

Deleting connectors

The source connector can be deleted using the following script debezium-delete.sh

The sink connector can be deleted using the following script sink-delete.sh

References

Kafka Connect REST API - (https://docs.confluent.io/platform/current/connect/references/restapi.html)

Connecting to a different MySQL instance(Host)

Add the following line to the debezium service in docker-compose.yml, so that debezium is able to access host.

extra_hosts:
- "host.docker.internal:host-gateway"

Make sure the mysqld.conf is modified with bind-address set to 0.0.0.0

Modify debezium configuration debezium-connector-setup-schema-registry.sh to set the MySQL host.

            "database.hostname": "host.docker.internal",

Grant access in MySQL server for debezium host

Caution about the security risks about WITH GRANT OPTION, refer manual

mysql> CREATE USER 'root'@'%' IDENTIFIED BY 'PASSWORD';
mysql> GRANT ALL PRIVILEGES ON *.* TO 'root'@'%' WITH GRANT OPTION;
mysql> FLUSH PRIVILEGES;

Topic Partitions.

By Default the kafka topic is created with number of partitions set to 1. For better throughput and High availability, its better to set to the partitions to a number greater than 1. The topic partitions must be created before the sink connector is started. For redpanda:

rpk topic create SERVER5432.test.employees -p 3