Delivering data from Yandex Managed Service for YDB to Yandex Managed Service for Apache Kafka® using Yandex Data Transfer

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). The system will automatically insert this data into Managed Service for Apache Kafka® topics with Managed Service for YDB table names.

To start data delivery:

1. Prepare the source.
2. Set up and activate the transfer.
3. Test your transfer.

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

Required paid resourcesRequired paid resources

• Managed Service for YDB database (see Managed Service for YDB pricing). Its cost depends on the deployment mode:

  • In serverless mode, you pay for data operations as well as the amount of stored data and backups.
  • In dedicated instance mode, you pay for the use of computing resources allocated to the database, storage size, and backups.

• Managed Service for Apache Kafka® cluster, which includes computing resources allocated to hosts, as well as the storage and backup size (see Managed Service for Apache Kafka® pricing).

• Public IP addresses if public access is enabled for cluster hosts (see Virtual Private Cloud pricing).

• Each transfer, which includes the use of computing resources and number of transferred data rows (see Data Transfer pricing).

Getting startedGetting started

1. Set up your data delivery infrastructure:

   Manually

   Terraform

   1. Create a Managed Service for YDB database of your preferred configuration.

   2. If you selected Dedicated database mode, create and configure a security group in the network hosting your database.

   3. Create a Managed Service for Apache Kafka® target cluster in any suitable configuration with publicly accessible hosts.

      Note

      Public access to cluster hosts is required if you plan to connect to the cluster via the internet. This connection option is simpler and is recommended for the purposes of this guide. You can connect to non-public hosts as well but only from Yandex Cloud virtual machines located in the same cloud network as the cluster.

   4. If using security groups, configure them to allow internet access to your cluster.

   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.

      • When managing topics using the native Yandex Cloud interfaces (management console, CLI, or API):

        1. Create a topic named cdc.sensors.

           To track changes in multiple tables, create a separate topic with the cdc prefix for each of them.

        2. 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.

      • When managing topics via the Kafka Admin API:

        1. Create an admin user.

        2. In addition to ACCESS_ROLE_ADMIN, assign the admin user the ACCESS_ROLE_CONSUMER and ACCESS_ROLE_PRODUCER roles for cdc.* topics whose names are prefixed with cdc.

           The system will automatically create the relevant topics upon the first change to the source cluster tables you are tracking. This solution can help tracking changes in multiple tables but it requires extra free space in the cluster storage. For more information, 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 for connecting to the Managed Service for Apache Kafka® cluster.
      • Managed Service for YDB database.
      • 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. You set it when running the terraform plan and terraform apply commands (see below):

      • When managing topics using the native Yandex Cloud interfaces (management console, CLI, or API):

        1. To track changes in multiple tables, add the descriptions of separate topics with the cdc prefix to the configuration file, one for each table.
        2. Set the kf_topics_management Terraform variable to false.

      • When managing topics using the Kafka Admin API, set the kf_topics_management Terraform variable to true.

   6. In the data-transfer-ydb-mkf.tf file, specify the following 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. Validate your Terraform configuration files using this command:

      terraform validate
      

      Terraform will display any configuration errors detected in your files.

   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:

         1. Run this command:

            terraform apply
            

         2. Confirm updating the resources.

         3. 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.

2. Install kafkacat for data reads and writes in Apache Kafka® topics.

   sudo apt update && sudo apt install --yes kafkacat
   

   Make sure you can use it to connect to the Managed Service for Apache Kafka® target cluster over SSL.

Prepare the sourcePrepare the source

1. Connect to the Managed Service for YDB database.

2. Create a YDB table. As an example, we will use the sensors table with data collected from some 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 the other settings.

   You can also create a table by running this 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 transferSet up and activate the transfer

1. 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 an existing service account or create a new one 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.

2. 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 credentials of the Apache Kafka® user you created.

     • Topic: Topic full name.

     • Topic full name: cdc.sensors.

     If you need to track changes in multiple tables, fill in the fields as follows:

     • Topic: Topic prefix.
     • Topic prefix: Enter the cdc prefix you used to generate topic names.

3. Create a transfer:

   Manually

   Terraform

   1. Create a transfer of the Replication type that will use the endpoints you created.
   2. Activate the transfer.

   1. In the data-transfer-ydb-mkf.tf file, specify the following variables:

      • source_endpoint_id: Source endpoint ID.
      • target_endpoint_id: Target endpoint ID.
      • transfer_enabled: Set to 1 to create a transfer.

   2. Validate your Terraform configuration files using this command:

      terraform validate
      

      Terraform will display any configuration errors detected in your files.

   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:

         1. Run this command:

            terraform apply
            

         2. Confirm updating the resources.

         3. Wait for the operation to complete.

      The transfer will be activated automatically upon creation.

Test your transferTest your transfer

1. Wait for the transfer status to change to Replicating.

2. In a separate terminal, run kafkacat 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.

3. 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);
   

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

   Message snippet example

   {
     "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 createdDelete the resources you created

To reduce the consumption of resources, delete those you do not need:

1. Delete the transfer.

2. Delete the source and target endpoints.

3. If you created a service account when creating the source endpoint, delete it.

4. Delete the other resources depending on how you created them:

   Manually

   Terraform

   1. Delete the Managed Service for Apache Kafka® cluster.
   2. Delete the Managed Service for YDB database.

   1. 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.

   2. 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.