Chapter 2. Installing Debezium connectors

Install Debezium connectors through AMQ Streams by extending Kafka Connect with connector plugins. Following a deployment of AMQ Streams, you can deploy Debezium as a connector configuration through Kafka Connect.

2.1. Prerequisites

A Debezium installation requires the following:

  • An OpenShift cluster
  • A deployment of AMQ Streams with Kafka Connect S2I
  • A user on the OpenShift cluster with cluster-admin permissions to set up the required cluster roles and API services
Note

Java 8 or later is required to run the Debezium connectors.

To install Debezium, the OpenShift Container Platform command-line interface (CLI) is required.

Additional resources

2.2. Kafka topic creation recommendations

Debezium uses multiple Kafka topics for storing data. The topics have to be either created by an administrator, or by Kafka itself by enabling auto-creation for topics using the auto.create.topics.enable broker configuration.

The following list describes limitations and recommendations to consider when creating topics:

Database history topics (for MySQL and SQL Server connectors)
  • Infinite (or very long retention).
  • Replication factor of at least 3 in production.
  • Single partition.
Other topics

  • Optionally, log compaction enabled (if you wish to only keep the last change event for a given record).

    In this case, the min.compaction.lag.ms and delete.retention.ms topic-level settings in Apache Kafka should be configured so that consumers have enough time to receive all events and delete markers. Specifically, these values should be larger than the maximum downtime you anticipate for the sink connectors (for example, when you update them).

  • Replicated in production.

  • Single partition.

    You can relax the single partition rule, but your application must handle out-of-order events for different rows in the database (events for a single row are still totally ordered). If multiple partitions are used, Kafka will determine the partition by hashing the key by default. Other partition strategies require using Simple Message Transforms (SMTs) to set the partition number for each record.

2.3. Deploying Debezium with AMQ Streams

This procedure describes how to set up connectors for Debezium on Red Hat OpenShift Container Platform.

Before you begin

For setting up Apache Kafka and Kafka Connect on OpenShift, Red Hat AMQ Streams is used. AMQ Streams offers operators and images that bring Kafka to OpenShift.

Here we deploy and use Kafka Connect S2I (Source to Image). S2I is a framework to build images that take application source code as an input and produce a new image that runs the assembled application as output.

A Kafka Connect builder image with S2I support is provided on the Red Hat Container Catalog as part of the registry.redhat.io/amq7/amq-streams-kafka-24:1.4.0 image. The S2I process takes your binaries (with plugins and connectors) and stores them in the /tmp/kafka-plugins/s2i directory. It creates a new Kafka Connect image from this directory, which can then be used with the Kafka Connect deployment. When started using the enhanced image, Kafka Connect loads any third-party plug-ins from the /tmp/kafka-plugins/s2i directory.

Note

Instead of deploying and using the Kafka Connect S2I, you can create a new Dockerfile based on an AMQ Streams Kafka image to include the connectors.

See Chapter 3, Creating a container image from the Kafka Connect base image.

In this procedure, we:

  • Deploy a Kafka cluster to OpenShift
  • Download and configure the Debezium connectors
  • Deploy Kafka Connect with the connectors

If you have a Kafka cluster deployed already, you can skip the first step.

Note

The pod names must correspond with your AMQ Streams deployment.

Procedure

  1. Deploy your Kafka cluster.

    1. Install the AMQ Streams operator by following the steps in Installing AMQ Streams and deploying components.
    2. Select the desired configuration and deploy your Kafka Cluster.
    3. Deploy Kafka Connect s2i.

    We now have a working Kafka cluster running in OpenShift with Kafka Connect S2I.

  2. Check that your pods are running: 

    $ oc get pods

NAME                                               READY STATUS
<cluster-name>-entity-operator-7b6b9d4c5f-k7b92    3/3   Running
<cluster-name>-kafka-0                             2/2   Running
<cluster-name>-zookeeper-0                         2/2   Running
<cluster-name>-operator-97cd5cf7b-l58bq            1/1   Running

    In addition to running pods you should have a DeploymentConfig associated with your Connect S2I.

  3. Select release 1.0, and download the Debezium connector archive for your database from the Red Hat Integration download site.

  4. Extract the archive to create a directory structure for the connector plugins. 

    $ tree ./my-plugin/
./my-plugin/
├── debezium-connector-mongodb
|   ├── ...
├── debezium-connector-mysql
│   ├── ...
├── debezium-connector-postgres
│   ├── ...
└── debezium-connector-sqlserver
    ├── ...

    Now we trigger the Kafka Connect S2I build.

  5. Check the name of the build config. 

    $ oc get buildconfigs

NAME                             TYPE     FROM     LATEST
<cluster-name>-cluster-connect   Source   Binary   2

  6. Use the oc start-build command to start a new build of the Kafka Connect image using the Debezium directory: 

    oc start-build <cluster-name>-cluster-connect --from-dir ./my-plugin/
    Note

    The name of the build is the same as the name of the deployed Kafka Connect cluster.

  7. Check the updated deployment is running: 

    oc get pods

NAME                                              READY     STATUS
<cluster-name>-entity-operator-7b6b9d4c5f-k7b92   3/3       Running
<cluster-name>-kafka-0                            2/2       Running
<cluster-name>-zookeeper-0                        2/2       Running
<cluster-name>-cluster-connect-2-jw695            1/1       Running
<cluster-name>-cluster-connect-2-deploy           0/1       Completed
strimzi-cluster-operator-97cd5cf7b-l58bq          1/1       Running

    Alternatively, you can go to the Pods view of your OpenShift Web Console to confirm the pods are running:

    openshift amq pods

Updating Kafka Connect

If you need to update your deployment, amend your JAR files in the Debezium directory and rebuild Kafka Connect.

Verifying the Deployment

Once the build has finished, the new image is used automatically by the Kafka Connect deployment.

When the connector starts, it will connect to the source and produce events for each inserted, updated, and deleted row or document.

Verify that deployment is correct by following the procedures in Getting Started with Debezium, Starting the services, which provides instructions for setting up a Kafka cluster and configuring Kafka Connect.

To set up a particular connector, see: