Migrating ClickHouse® clusters

Written by

Yandex Cloud

Updated at January 21, 2025

Prepare the source cluster.
Prepare the infrastructure:
Manually

Using Terraform
1. Create a security group and configure it.
2. Create a Managed Service for ClickHouse® target cluster with the computing capacity and storage size appropriate for the environment where the copied database is deployed.
  
  When creating a cluster, specify the security group prepared earlier.
  
  The database name in the target cluster must be the same as the source database name.
3. Create a source endpoint:
  - Database type: ClickHouse
  - Endpoint parameters → Connection settings: On-premise
    
    Specify the parameters for connecting to the source cluster.
4. Create a target endpoint:
  - Database type: ClickHouse
  - Endpoint parameters → Connection settings: Managed cluster
    
    Select a target cluster from the list and specify its connection settings.
5. Create a transfer of the Snapshot type that will use the created endpoints.
6. Activate your transfer.
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-ch-mch.tf configuration file to the same working directory.
  
  This file describes:
  - Network.
  - Subnet.
  - Security group and the rule required to connect to a cluster.
  - Managed Service for ClickHouse® target cluster.
  - Source endpoint.
  - Target endpoint.
  - Transfer.
6. Specify the following in the data-transfer-ch-mch.tf file:
  - Source endpoint parameters:
    
    source_user and source_pwd: Username and password to access the source.
    
    source_db_name: Database name.
    
    source_host: FQDN or IP address of the ClickHouse® server.
    
    source_shard: Shard name.
    
    source_http_port and source_native_port: HTTP and ClickHouse® native interface connection ports.
  - Target cluster parameters also used as target endpoint parameters:
    
    target_clickhouse_version: ClickHouse® version.
    
    target_user and target_password: Name and user password of the database owner.
7. Check that 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.
  
  Once created, your transfer will be activated automatically.
Wait for the transfer status to change to Completed.

For more information about transfer statuses, see Transfer lifecycle.
Some resources are not free of charge. To avoid paying for them, delete the resources you no longer need:
Manually

Using Terraform
- Delete the Managed Service for ClickHouse® cluster.
- Delete the completed transfer.
- Delete endpoints for both the source and target.
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.

Migrating ClickHouse® clusters

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