YDB change data capture and delivery to Apache Kafka®

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Updated at May 5, 2025

Required paid resources
Getting started
Prepare the source
Set up and activate the transfer
Test your transfer
Delete the resources you created

You can track data changes in a Managed Service for YDB source and send them to a Managed Service for Apache Kafka® target cluster using Change Data Capture (CDC). This data is automatically added to Managed Service for Apache Kafka® topics with Managed Service for YDB table names.

Note

In YDB, CDC mode is supported starting from version 22.5.

To run data delivery:

If you no longer need the resources you created, delete them.

Required paid resources

The support cost includes:

Fee for the Managed Service for YDB database. The charge depends on the usage mode:
- For the serverless mode, you pay for data operations and the amount of stored data.
- For the dedicated instance mode, you pay for the use of computing resources, dedicated DBs, and disk space.
Learn more about the Managed Service for YDB pricing plans.
Managed Service for Apache Kafka® cluster fee: Using computing resources allocated to hosts (including ZooKeeper hosts) and disk space (see Apache Kafka® pricing).
Fee for using public IP addresses for cluster hosts (see Virtual Private Cloud pricing).

Getting started

Prepare the data transfer infrastructure:
Manually

Terraform
1. Create a Managed Service for YDB database in any suitable configuration.
2. If you selected Dedicated DB mode, create and configure a security group in the network hosting the DB.
3. Create a Managed Service for Apache Kafka® target cluster in any suitable configuration with publicly available hosts.
4. If you are using security groups, configure them so that you can connect to the cluster from the internet.
5. Configure Apache Kafka® topics in the target cluster. The settings vary depending on the topic management method used. The format for data topic names is as follows: <topic_prefix>.<YDB_table_name>. In this tutorial, we will use the cdc prefix as an example.
  - If topics are managed using standard Yandex Cloud interfaces (management console, CLI, or API):
    
    Create a topic named cdc.sensors.
    
    To track changes in multiple tables, create a separate topic with the cdc prefix for each of them.
    
    Create a user with the ACCESS_ROLE_CONSUMER and ACCESS_ROLE_PRODUCER roles for the cdc.sensors topic. To include all created topics, specify cdc.* in the topic name.
  - If topics are managed using the Kafka Admin API:
    
    Create an admin user.
    
    In addition to ACCESS_ROLE_ADMIN, assign the admin user the ACCESS_ROLE_CONSUMER and ACCESS_ROLE_PRODUCER roles for cdc.* topics whose names begin with the cdc prefix.
    
    Required topics will be created automatically upon the first change to the source cluster tables you are tracking. This solution can be useful to track changes in multiple tables but requires extra free space in the cluster storage. To learn more, see Storage in Managed Service for Apache Kafka®.
1. If you do not have Terraform yet, install it.
2. Get the authentication credentials. You can add them to environment variables or specify them later in the provider configuration file.
3. Configure and initialize a provider. There is no need to create a provider configuration file manually, you can download it.
4. Place the configuration file in a separate working directory and specify the parameter values. If you did not add the authentication credentials to environment variables, specify them in the configuration file.
5. Download the data-transfer-ydb-mkf.tf configuration file to the same working directory.
  
  This file describes:
  - Network.
  - Subnet.
  - Security group and the rule required to connect to a Managed Service for Apache Kafka® cluster.
  - Database: Managed Service for YDB.
  - Managed Service for Apache Kafka® target cluster.
  - Apache Kafka® topic.
  - Apache Kafka® user.
  - Transfer.
  The topic management method is specified in the kf_topics_management Terraform variable. It is set when running the terraform plan and terraform apply commands (see below):
  - If topics are managed using standard Yandex Cloud interfaces (management console, CLI, or API):
    
    To track changes in multiple tables, add the descriptions of the separate topics with the cdc prefix to the configuration file, one for each table.
    
    Set the kf_topics_management Terraform variable to false.
  - If the topics are managed using the Kafka Admin API, set the kf_topics_management Terraform variable to true.
6. In the data-transfer-ydb-mkf.tf file, specify these variables:
  - source_db_name: Managed Service for YDB database name.
  - target_kf_version: Apache Kafka® version in the target cluster.
  - target_user_name: Username for connection to the Apache Kafka® topic.
  - target_user_password: User password.
  - transfer_enabled: Set to 0 to ensure no transfer is created until you create endpoints manually.
7. Make sure the Terraform configuration files are correct using this command:
  terraform validate
  If there are any errors in the configuration files, Terraform will point them out.
8. Create the required infrastructure:
  1. Run this command to view the planned changes:
    
    terraform plan
    
    If you described the configuration correctly, the terminal will display a list of the resources to update and their parameters. This is a verification step that does not apply changes to your resources.
  2. If everything looks correct, apply the changes:
    
    Run this command:
    
    terraform apply
    
    Confirm updating the resources.
    
    Wait for the operation to complete.
  All the required resources will be created in the specified folder. You can check resource availability and their settings in the management console.
Install kafkacat to read and write data to Apache Kafka® topics.
```
sudo apt update && sudo apt install --yes kafkacat
```
Check that you can use it to connect to the Managed Service for Apache Kafka® target cluster over SSL.

Prepare the source

Connect to the Managed Service for YDB database.

Create a YDB table. As an example, we will use the sensors table with information collected, let’s say, from car sensors.

Add the following columns to the table manually:

Name	Type	Primary key
`device_id`	`String`	Yes
`datetime`	`String`
`latitude`	`Double`
`longitude`	`Double`
`altitude`	`Double`
`speed`	`Double`
`battery_voltage`	`Double`
`cabin_temperature`	`Uint8`
`fuel_level`	`Uint32`

Leave the default values for other settings.

You can also create a table with the following YQL command:

CREATE TABLE sensors (
    device_id String,
    datetime String,
    latitude Double,
    longitude Double,
    altitude Double,
    speed Double,
    battery_voltage Double,
    cabin_temperature Uint8,
    fuel_level Uint32,
    PRIMARY KEY (device_id)
)

Set up and activate the transfer

Create a source endpoint:
- Database type: YDB.
- Endpoint parameters:
  - Connection settings:
    - Database: Select the Managed Service for YDB database from the list.
    - Service account ID: Select or create a service account with the editor role.
  - Included paths list: Specify the names of tables and Managed Service for YDB database directories to transfer.
    
    Warning
    
    Only the listed tables and directories will be replicated. If you do not specify any names, no tables will be transferred.
Create a target endpoint:
- Database type: Kafka.
- Endpoint parameters:
  - Connection type: Managed Service for Apache Kafka cluster
    - Managed Service for Apache Kafka cluster: Select the previously created Managed Service for Apache Kafka® source cluster.
    - Authentication: Specify the details of the created Apache Kafka® user.
  - Topic: Topic full name.
  - Topic full name: cdc.sensors.
  If you need to track changes in multiple tables, fill out the fields as follows:
  - Topic: Topic prefix.
  - Topic prefix: Enter the cdc prefix you used to generate topic names.
Create a transfer:
Manually

Terraform
1. Create a transfer of the Replication type that will use the endpoints you created.
2. Activate your transfer.
1. In the data-transfer-ydb-mkf.tf file, specify these variables:
  - source_endpoint_id: ID of the source endpoint.
  - target_endpoint_id: Target endpoint ID.
  - transfer_enabled: 1 to create a transfer.
2. Make sure the Terraform configuration files are correct using this command:
  terraform validate
  If there are any errors in the configuration files, Terraform will point them out.
3. Create the required infrastructure:
  1. Run this command to view the planned changes:
    
    terraform plan
    
    If you described the configuration correctly, the terminal will display a list of the resources to update and their parameters. This is a verification step that does not apply changes to your resources.
  2. If everything looks correct, apply the changes:
    
    Run this command:
    
    terraform apply
    
    Confirm updating the resources.
    
    Wait for the operation to complete.
  Once created, your transfer will be activated automatically.

Test your transfer

Wait until the transfer status switches to Replicating.

In a separate terminal, run the kafkacat utility in consumer mode:

kafkacat \
    -C \
    -b <broker_host_1_FQDN>:9091,...,<broker_host_N_FQDN>:9091 \
    -t cdc.sensors \
    -X security.protocol=SASL_SSL \
    -X sasl.mechanisms=SCRAM-SHA-512 \
    -X sasl.username=kafka-user \
    -X sasl.password=<password> \
    -X ssl.ca.location=/usr/local/share/ca-certificates/Yandex/YandexInternalRootCA.crt \
    -Z \
    -K:

You can get the FQDNs of broker hosts with the list of hosts in the Managed Service for Apache Kafka® cluster.

Connect to the Managed Service for YDB database and add test data to the sensors table:

REPLACE INTO sensors (device_id, datetime, latitude, longitude, altitude, speed, battery_voltage, cabin_temperature, fuel_level) VALUES 
    ('iv9a94th6rzt********', '2022-06-05 17:27:00', 55.70329032, 37.65472196, 427.5, 0, 23.5, 17, NULL),
    ('rhibbh3y08qm********', '2022-06-06 09:49:54', 55.71294467, 37.66542005, 429.13, 55.5, NULL, 18, 32),
    ('iv9a94th6rzt********', '2022-06-08 17:45:00', 53.70987913, 36.62549834, 378.0, NULL, 20.5, 15, 20);

Make sure the terminal running the kafkacat utility displays the data format schema of the sensors table and information about the added rows.

Example of the message fragment

{
  "payload": {
      "device_id": "aXY5YTk0dGg2cnp0b294********"
    },
    "schema": {
      "fields": [
        {
            "field": "device_id",
            "optional": false,
            "type": "bytes"
        }
      ],
      "name": "cdc..sensors.Key",
      "optional": false,
      "type": "struct"
    }
}: {
  "payload": {
    "after": {
        "altitude": 378,
        "battery_voltage": 20.5,
        "cabin_temperature": 15,
        "datetime": "MjAyMi0wNi0wOCAxNzo0********",
        "device_id": "aXY5YTk0dGg2cnp0b294********",
        "fuel_level": 20,
        "latitude": 53.70987913,
        "longitude": 36.62549834,
        "speed": null
    },
    "before": null,
    "op": "c",
    "source": {
        "db": "",
        "name": "cdc",
        "snapshot": "false",
        "table": "sensors",
        "ts_ms": 1678642104797,
        "version": "1.1.2.Final"
    },
    "transaction": null,
    "ts_ms": 1678642104797
  },
  "schema": {
    "fields": [
        {
            "field": "before",
            "fields": [
                {
                    "field": "device_id",
                    "optional": false,
                    "type": "bytes"
                },
                ...
            ],
            "name": "cdc..sensors.Value",
            "optional": true,
            "type": "struct"
        },
        {
            "field": "after",
            "fields": [
                {
                    "field": "device_id",
                    "optional": false,
                    "type": "bytes"
                },
                ...
            ],
            "name": "cdc..sensors.Value",
            "optional": true,
            "type": "struct"
        },
        {
            "field": "source",
            "fields": [
                {
                    "field": "version",
                    "optional": false,
                    "type": "string"
                },
                {
                    "field": "connector",
                    "optional": false,
                    "type": "string"
                },
                {
                    "field": "name",
                    "optional": false,
                    "type": "string"
                },
                {
                    "field": "ts_ms",
                    "optional": false,
                    "type": "int64"
                },
                {
                    "default": "false",
                    "field": "snapshot",
                    "name": "io.debezium.data.Enum",
                    "optional": true,
                    "parameters": {
                        "allowed": "true,last,false"
                    },
                    "type": "string",
                    "version": 1
                },
                {
                    "field": "db",
                    "optional": false,
                    "type": "string"
                },
                {
                    "field": "table",
                    "optional": false,
                    "type": "string"
                }
            ],
            "optional": false,
            "type": "struct"
        },
        ...,
        {
            "field": "transaction",
            "fields": [
                {
                    "field": "id",
                    "optional": false,
                    "type": "string"
                },
                {
                    "field": "total_order",
                    "optional": false,
                    "type": "int64"
                },
                {
                    "field": "data_collection_order",
                    "optional": false,
                    "type": "int64"
                }
            ],
            "optional": true,
            "type": "struct"
        }
    ],
    "name": "cdc..sensors.Envelope",
    "optional": false,
    "type": "struct"
  }
}

Delete the resources you created

Note

Before deleting the resources you created, deactivate the transfer.

Some resources are not free of charge. To avoid paying for them, delete the resources you no longer need:

Delete the transfer.
Delete the endpoints for both the source and target.
If you had created a service account when creating the source endpoint, delete it.

Delete the other resources depending on how they were created:

Manually

Terraform

In the terminal window, go to the directory containing the infrastructure plan.

Warning

Make sure the directory has no Terraform manifests with the resources you want to keep. Terraform deletes all resources that were created using the manifests in the current directory.
Delete resources:
1. Run this command:
```
terraform destroy
```
2. Confirm deleting the resources and wait for the operation to complete.
All the resources described in the Terraform manifests will be deleted.

YDB change data capture and delivery to Apache Kafka®

Required paid resourcesRequired paid resources

Getting startedGetting started

Prepare the sourcePrepare the source

Set up and activate the transferSet up and activate the transfer

Test your transferTest your transfer

Delete the resources you createdDelete the resources you created