Delivering data from an Apache Kafka® queue to YDB

Written by

Updated at September 24, 2024

Getting started
Prepare and activate the transfer
Test the transfer
Delete the resources you created

A Managed Service for YDB cluster can get data from Apache Kafka® topics in real time. This data is automatically added to YDB tables with topic names.

To run data delivery:

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

Getting started

Prepare the data transfer infrastructure:
Manually

Terraform
1. Create a Managed Service for Apache Kafka® source cluster with any suitable configuration.
2. Create a Managed Service for YDB database in any suitable configuration.
3. In the source cluster, create a topic named sensors.
4. In the source cluster, create a user with the ACCESS_ROLE_PRODUCER and ACCESS_ROLE_CONSUMER permissions for the created topic.
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-mkf-ydb.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.
  - Managed Service for Apache Kafka® source cluster.
  - Apache Kafka® topic.
  - Apache Kafka® user.
  - Managed Service for YDB database.
  - Transfer.
6. In the data-transfer-mkf-ydb.tf file, specify the variables:
  - source_kf_version: Apache Kafka® version in the source cluster.
  - source_user_name: Username for establishing a connection to the Apache Kafka® topic.
  - source_user_password: User password.
  - target_db_name: Managed Service for YDB database name.
  - transfer_enabled: Set 0 to ensure that no transfer is created before creating a target endpoint 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 the command to view planned changes:
    
    terraform plan
    
    If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
  2. If you are happy with the planned changes, apply them:
    
    Run the command:
    
    terraform apply
    
    Confirm the update of 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.
The created Apache Kafka® sensors topic in the source cluster will receive test data from car sensors in JSON format:
```
{
    "device_id":"iv9a94th6rzt********",
    "datetime":"2020-06-05 17:27:00",
    "latitude":"55.70329032",
    "longitude":"37.65472196",
    "altitude":"427.5",
    "speed":"0",
    "battery_voltage":"23.5",
    "cabin_temperature":"17",
    "fuel_level":null
}
```
Install the utilities:
- 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® source cluster over SSL.
- jq for JSON file stream processing.
```
sudo apt update && sudo apt-get install --yes jq
```

Prepare and activate the transfer

Create a target 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.

Create a source endpoint:

Database type: Kafka.

Endpoint parameters:

Connection type: Managed Service for Apache Kafka cluster.

Select a source cluster from the list and specify its connection settings.

Advanced settings → Conversion rules.

Data format: JSON.

Data scheme: You can specify a schema in two ways:

Field list.

Set a list of topic fields manually:

Name	Type	Key
`device_id`	`STRING`	Yes
`datetime`	`STRING`
`latitude`	`DOUBLE`
`longitude`	`DOUBLE`
`altitude`	`DOUBLE`
`speed`	`DOUBLE`
`battery_voltage`	`DOUBLE`
`cabin_temperature`	`UINT16`
`fuel_level`	`UINT16`

JSON specification.

Create and upload the json_schema.json file in JSON format:

json_schema.json

[
    {
        "name": "device_id",
        "type": "string",
        "key": true
    },
    {
        "name": "datetime",
        "type": "string"
    },
    {
        "name": "latitude",
        "type": "double"
    },
    {
        "name": "longitude",
        "type": "double"
    },
    {
        "name": "altitude",
        "type": "double"
    },
    {
        "name": "speed",
        "type": "double"
    },
    {
        "name": "battery_voltage",
        "type": "double"
    },
    {
        "name": "cabin_temperature",
        "type": "uint16"
    },
    {
        "name": "fuel_level",
        "type": "uint16"
    }
]

Create a transfer:
Manually

Terraform
1. Create a transfer of the Replication type that will use the created endpoints.
2. Activate your transfer.
1. In the data-transfer-mkf-ydb.tf file, specify the variables:
  - source_endpoint_id: ID of the source endpoint.
  - target_endpoint_id: ID of the target endpoint.
  - transfer_enabled: Set to 1 to enable transfer creation.
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 the command to view planned changes:
    
    terraform plan
    
    If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
  2. If you are happy with the planned changes, apply them:
    
    Run the command:
    
    terraform apply
    
    Confirm the update of resources.
    
    Wait for the operation to complete.
  Once created, your transfer will be activated automatically.

Test the transfer

Wait for the transfer status to change to Replicating.

Make sure the data from the topic in the source Managed Service for Apache Kafka® cluster is being moved to the Managed Service for YDB database:

Create a sample.json file with the following test data:

{
    "device_id": "iv9a94th6rzt********",
    "datetime": "2020-06-05 17:27:00",
    "latitude": 55.70329032,
    "longitude": 37.65472196,
    "altitude": 427.5,
    "speed": 0,
    "battery_voltage": 23.5,
    "cabin_temperature": 17,
    "fuel_level": null
}

{
    "device_id": "rhibbh3y08qm********",
    "datetime": "2020-06-06 09:49:54",
    "latitude": 55.71294467,
    "longitude": 37.66542005,
    "altitude": 429.13,
    "speed": 55.5,
    "battery_voltage": null,
    "cabin_temperature": 18,
    "fuel_level": 32
}

{
    "device_id": "iv9a94th6rzt********",
    "datetime": "2020-06-07 15:00:10",
    "latitude": 55.70985913,
    "longitude": 37.62141918,
    "altitude": 417.0,
    "speed": 15.7,
    "battery_voltage": 10.3,
    "cabin_temperature": 17,
    "fuel_level": null
}

Send data from the sample.json file to the Managed Service for Apache Kafka® sensors topic using jq and kafkacat:

jq -rc . sample.json | kafkacat -P \
   -b <broker_host_FQDN>:9091 \
   -t sensors \
   -k key \
   -X security.protocol=SASL_SSL \
   -X sasl.mechanisms=SCRAM-SHA-512 \
   -X sasl.username="<username_in_the_source_cluster>" \
   -X sasl.password="<user_password_in_the_source_cluster>" \
   -X ssl.ca.location=/usr/local/share/ca-certificates/Yandex/YandexInternalRootCA.crt -Z

The data is sent on behalf of the created user. To learn more about setting up an SSL certificate and working with kafkacat, see Connecting to an Apache Kafka® cluster from applications.

Make sure the data from the source Managed Service for Apache Kafka® cluster has been moved to the Managed Service for YDB database:
Management console

YDB CLI
1. In the management console, select the folder with the DB you need.
2. In the list of services, select Managed Service for YDB.
3. Select the database from the list.
4. Go to the Navigation tab.
5. Check that the Managed Service for YDB database contains the sensors table with the test data from the topic.
1. Connect to the Managed Service for YDB database.
2. Check that the database contains the sensors table with the test data from the topic:
  ydb table query execute \ --query "SELECT * \ FROM sensors"

Delete the resources you created

Note

Before deleting the created resources, 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 endpoints for both the source and target.
If you created a service account together with the target 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.
Delete the data-transfer-mkf-ydb.tf configuration file.
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.
Confirm updating the resources.
1. Run the command to view planned changes:
```
terraform plan
```
  If the resource configuration descriptions are correct, the terminal will display a list of the resources to modify and their parameters. This is a test step. No resources are updated.
2. If you are happy with the planned changes, apply them:
  1. Run the command:
```
terraform apply
```
  2. Confirm the update of resources.
  3. Wait for the operation to complete.
All the resources described in the configuration file data-transfer-mkf-ydb.tf will be deleted.

Delivering data from an Apache Kafka® queue to YDB

Getting startedGetting started

Prepare and activate the transferPrepare and activate the transfer

Test the transferTest the transfer

Delete the resources you createdDelete the resources you created

Was the article helpful?

Getting started

Prepare and activate the transfer

Test the transfer

Delete the resources you created