Create a migration job to an existing destination instance

MySQL   |  PostgreSQL   |  PostgreSQL to AlloyDB

Overview

Database Migration Service uses migration jobs to migrate data from your source database instance to the destination database instance. Creating a migration job for an existing destination instance includes:

• Defining settings for the migration job
• Selecting the source database connection profile
• Selecting the existing destination database instance
• Demoting the existing instance to convert it into a read replica
• Setting up connectivity between the source and destination database instances
• Testing the migration job to ensure that the connection information you provided for the job is valid

There are certain limitations that you should consider when you want to migrate to a destination instance created outside of Database Migration Service. For example, your Cloud SQL destination instance must be empty or contain only system configuration data. For more information, see Known Limitations.

Create a migration job by using the Google Cloud console

Database Migration Service comes equipped with a wizard to help you create a migration job. This wizard consists of five panels: Get started, Define a source, Create a destination, Define connectivity method, and Test and create migration job. Information on how to populate each panel is provided in the various sections of this page.

You can pause the creation of a migration job by clicking Save and exit. All of the data that was populated until that point is saved in a draft migration job, and you can access this job in a Drafts tab.

To finish creating a migration job, navigate to the tab, and then click the job. The creation flow resumes from where it was left off. The job remains a draft until you click Create or Create and start.

Define settings for the migration job

1. Go to the Migration jobs in the Google Cloud console.

2. Click Create migration job at the top of the page.

3. Provide a name for the migration job. Choose a friendly name that helps you identify the migration job. Don't include sensitive or personally identifiable information in the job name.

4. Keep the auto-generated Migration job ID.

5. Select the source database engine.

6. Select the destination database engine.

7. Select the destination region for your migration. This region must be the same as the one where your destination database is located. After you choose the destination region, this selection can't be changed.

   Important: If you plan to use the Cloud SQL for PostgreSQL Enterprise Plus edition, make sure your region is supported for that edition. See Cloud SQL for PostgreSQL Enterprise Plus edition region support.

8. Specify the migration job type: One-time (snapshot only) or Continuous (snapshot + ongoing changes).

9. In the Before you continue, review the prerequisites section, click Open to view automatically generated instructions that can help guide you through preparing your source database for the migration. It's best to complete these prerequisites at this step, but you can complete them at any time before you test, or start, the migration job. For more information, see Configure your source.

10. Click Save and continue.

Specify information about the source connection profile

1. If you have created a connection profile, then select it from the list of existing connection profiles.

   If you haven't created a connection profile, then create one by clicking Create a connection profile at the bottom of the drop-down list, and then perform the same steps as in Create a source connection profile.

2. In the Customize initial load configurations section, click Show advanced settings.

   The speed of data parallelism is related to the amount of load on your source database. You can use the following settings:

   • Optimal (recommended): Balanced performance with optimal load on the source database.
   • Maximum: Provides the highest dump speeds, but might cause increased load on the source database.
   • Minimum: Takes the lowest amount of compute resources on the source database, but might have slower dump throughput.

   If you want to use adjusted initial load parallelism settings, make sure to increase the max_replication_slots, max_wal_senders, and max_worker_processes parameters on your source database. You can verify your configuration by running the migration job test at the end of migration job creation.

3. Click Save and continue.

Select the destination instance

Note: For Cloud SQL sources: If you are migrating from a Cloud SQL instance that uses a Private IP connection to a Cloud SQL instance that uses a non-RFC 1918 address IP range, add the non-RFC 1918 range to the network configuration of your source Cloud SQL instance. See Configure authorized networks in Cloud SQL documentation.

1. From the Type of destination instance menu, select Existing instance.

2. In the Select destination instance section, select your destination instance.

3. Review the information in the Instance details section, and click Select and continue.

4. To migrate to an existing destination database, Database Migration Service demotes the target instance and converts it to a replica. To signify that the demotion can be safely performed, in the confirmation window, enter the destination instance identifier.

5. Click Confirm and continue.

Set up connectivity between the source and destination database instances

If you're reusing a source connection profile that was used previously for heterogeneous migrations (for example, from Oracle to Cloud SQL to PostgreSQL), then in this step, you must choose a connectivity method. This method will be used for the homogeneous migration from one Cloud SQL for PostgreSQL database instance to another. You must select a connectivity method because the heterogeneous connectivity method isn't relevant for this migration job.

1. From the Connectivity method drop-down menu, select a network connectivity method. This method defines how the newly created Cloud SQL instance will connect to the source database. Current network connectivity methods include IP allowlist, reverse SSH tunnel, and VPC peering.

   • If you select the IP allowlist network connectivity method, you need to specify the outgoing IP address of your destination instance. If the Cloud SQL instance you created is a high availability instance, include the outgoing IP addresses for both the primary and the secondary instance.

   • If you select the reverse SSH tunnel network connectivity method, then select the Compute Engine VM instance that will host the tunnel.

     After specifying the instance, Google will provide a script that performs the steps to set up the tunnel between the source and destination databases. You'll need to run the script in the Google Cloud CLI.

     Run the commands from a machine that has connectivity to both the source database and to Google Cloud.

   • If you select the VPC peering network connectivity method, then select the VPC network where the source database resides. The Cloud SQL instance will be updated to connect to this network.
   • Learn more about how to Configure connectivity.

2. After selecting the network connectivity method and providing any additional information for the method, click CONFIGURE & CONTINUE.

Test and create the migration job

On this final step, review the summary of the migration job settings, source, destination, and connectivity method, and then test the validity of the migration job setup. If any issues are encountered, then you can modify the migration job's settings. Not all settings are editable.

1. Click TEST JOB to verify that:

   • The source database has been configured correctly, based on the prerequisites.
   • The source and destination instances can communicate with each other.
   • Any updates to private or public IP addresses needed on the destination are done.
   • The migration job is valid, and the source and destination versions are compatible.

   If the test fails, then you can address the problem in the appropriate part of the flow, and return to re-test.

   For more information about reasons why the test might fail and how to troubleshoot any issues associated with the test failing, see Diagnose issues for PostgreSQL.

   The migration job can be created even if the test fails, but after the job is started, it may fail at some point during the run.

2. Click CREATE & START JOB to create the migration job and start it immediately, or click CREATE JOB to create the migration job without immediately starting it.

   Caution: If you used Terraform to provision your destination database, you might experience configuration drift during the migration job execution. Don't try to re-apply Terraform settings before the migration is complete. For more information, see Terraform configuration drift.

   If the job isn't started at the time that it's created, then it can be started from the Migration jobs page by clicking START.

   Regardless of when the migration job starts, your organization is charged for the existence of the destination instance.

   When you start the migration job, Database Migration Service begins the full dump, briefly locking the source database. If your source is in Amazon RDS or Amazon Aurora, Database Migration Service additionally requires a short (approximately under a minute) write downtime at the start of the migration. For more information, see Data dump parallelism considerations.

3. The migration job is added to the migration jobs list and can be viewed directly.

4. Proceed to Review the migration job.

Create a migration job by using Google Cloud CLI

When you migrate to an existing instance by using Google Cloud CLI, you must manually create the connection profile for the destination instance. This isn't required when you use the Google Cloud console, as Database Migration Service takes care of creating and removing the destination connection profile for you.

Before you begin

Before you use gcloud CLI to create a migration job to an existing destination database instance, make sure you:

• Create your destination database instance.
• Prepare your source database instance. See:
  • Configure your source
  • Create the source connection profile (Source connection profile identifier is required to create a migration job.)
  • Configure connectivity

Create destination connection profile

Create the destination connection profile for your existing destination instance by running the gcloud database-migration connection-profiles create command:

This sample uses the optional --no-async flag so that all operations are performed synchronously. This means that some commands might take a while to complete. You can skip the --no-async flag to run commands asynchronously. If you do, you need to use the gcloud database-migration operations describe command to verify if your operation is successful.

Before using any of the command data below, make the following replacements:

• CONNECTION_PROFILE_ID with a machine-readable identifier for your connection profile.
• REGION with the identifier of the region where you want to save the connection profile.
• DESTINATION_INSTANCE_ID with the instance identifier of your destination instance.
• (Optional) CONNECTION_PROFILE_NAME with a human-readable name for your connection profile. This value is displayed in the Google Cloud console.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration connection-profiles \
create postgresql CONNECTION_PROFILE_ID \
  --no-async \
  --cloudsql-instance=CLOUDSQL_INSTANCE_ID \
  --region=REGION \
  --display-name=CONNECTION_PROFILE_NAME

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration connection-profiles `
create postgresql CONNECTION_PROFILE_ID `
  --no-async `
  --cloudsql-instance=CLOUDSQL_INSTANCE_ID `
  --region=REGION `
  --display-name=CONNECTION_PROFILE_NAME

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration connection-profiles ^
create postgresql CONNECTION_PROFILE_ID ^
  --no-async ^
  --cloudsql-instance=CLOUDSQL_INSTANCE_ID ^
  --region=REGION ^
  --display-name=CONNECTION_PROFILE_NAME

You should receive a response similar to the following:

Waiting for connection profile [CONNECTION_PROFILE_ID]
to be created with [OPERATION_ID]

Waiting for operation [OPERATION_ID] to complete...done.

Created connection profile CONNECTION_PROFILE_ID [OPERATION_ID]

Create the migration job

Note: The following examples represent a migration scenario where you use the Private IP connectivity between the source and destination databases. If you use a different connectivity type (for example VPC peering or a reverse-SSH tunnel), make sure to add the required flags, such as --peer-vpc, or --vm, --vm-ip, --vm-port, --vpc. For more informations, see Configure connectivity and Google Cloud CLI examples.

Note: Only continuous migration type is supported for migrations to Database Migration Service for PostgreSQL.

This sample uses the optional --no-async flag so that all operations are performed synchronously. This means that some commands might take a while to complete. You can skip the --no-async flag to run commands asynchronously. If you do, you need to use the gcloud database-migration operations describe command to verify if your operation is successful.

Before using any of the command data below, make the following replacements:

• MIGRATION_JOB_ID with a machine-readable identifier for your migration job. You use this value to work with migration jobs by using Database Migration Service Google Cloud CLI commands or API.
• REGION with the region identifier where you want to save the migration job.
• MIGRATION_JOB_NAME with a human-readable name for your migration job. This value is displayed in Database Migration Service in the Google Cloud console.
• SOURCE_CONNECTION_PROFILE_ID with a machine-readable identifier of the source connection profile.
• DESTINATION_CONNECTION_PROFILE_ID with a machine-readable identifier of the destination connection profile.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs \
create MIGRATION_JOB_ID \
  --no-async \
  --region=REGION \
  --display-name=MIGRATION_JOB_NAME \
  --source=SOURCE_CONNECTION_PROFILE_ID \
  --destination=DESTINATION_CONNECTION_PROFILE_ID \

  --type=CONTINUOUS

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs `
create MIGRATION_JOB_ID `
  --no-async `
  --region=REGION `
  --display-name=MIGRATION_JOB_NAME `
  --source=SOURCE_CONNECTION_PROFILE_ID `
  --destination=DESTINATION_CONNECTION_PROFILE_ID `

  --type=CONTINUOUS

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs ^
create MIGRATION_JOB_ID ^
  --no-async ^
  --region=REGION ^
  --display-name=MIGRATION_JOB_NAME ^
  --source=SOURCE_CONNECTION_PROFILE_ID ^
  --destination=DESTINATION_CONNECTION_PROFILE_ID ^

  --type=CONTINUOUS

You should receive a response similar to the following:

Waiting for migration job [MIGRATION_JOB_ID]
to be created with [OPERATION_ID]

Waiting for operation [OPERATION_ID] to complete...done.

Created migration job MIGRATION_JOB_ID [OPERATION_ID]

Demote the destination database

Database Migration Service requires that the destination database instance works as a read replica for the time of migration. Before you start the migration job, run the gcloud database-migration migration-jobs demote-destination command to demote the destination database instance.

Before using any of the command data below, make the following replacements:

• MIGRATION_JOB_ID with your migration job identifier.

  If you don't know the identifier, you can use the gcloud database-migration migration-jobs list command to list all migration jobs in a given region and view their identifiers.

• REGION with the identifier of the region where your connection profile is saved.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs \
demote-destination MIGRATION_JOB_ID \
  --region=REGION

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs `
demote-destination MIGRATION_JOB_ID `
  --region=REGION

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs ^
demote-destination MIGRATION_JOB_ID ^
  --region=REGION

Result

The action is performed in an asynchronous manner. As such, this command returns an Operation entity that represents a long-running operation:

done: false
metadata:
  '@type': type.googleapis.com/google.cloud.clouddms.v1.OperationMetadata
  apiVersion: v1
  createTime: '2024-02-20T12:20:24.493106418Z'
  requestedCancellation: false
  target: MIGRATION_JOB_ID
  verb: demote-destination
name: OPERATION_ID

To see if your operation is successful, you can query the returned operation object, or check the status of the migration job:

• Use the gcloud database-migration migration-jobs describe command to view the status of the migration job.
• Use the gcloud database-migration migration-jobs describe with the OPERATION_ID to see the status of the operation itself.

Manage migration jobs

At this point, your migration job is configured and connected to your destination database instance. You can manage it by using the verify,start, stop, restart, and resume operations.

Verify the migration job

We recommend you first verify your migration job, by running the gcloud database-migration migration-jobs verify command.

Before using any of the command data below, make the following replacements:

• MIGRATION_JOB_ID with your migration job identifier.

  If you don't know the identifier, you can use the gcloud database-migration migration-jobs list command to list all migration jobs in a given region and view their identifiers.

• REGION with the identifier of the region where your connection profile is saved.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs \
verify MIGRATION_JOB_ID \
  --region=REGION

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs `
verify MIGRATION_JOB_ID `
  --region=REGION

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs ^
verify MIGRATION_JOB_ID ^
  --region=REGION

Result

The action is performed in an asynchronous manner. As such, this command returns an Operation entity that represents a long-running operation:

done: false
metadata:
  '@type': type.googleapis.com/google.cloud.clouddms.v1.OperationMetadata
  apiVersion: v1
  createTime: '2024-02-20T12:20:24.493106418Z'
  requestedCancellation: false
  target: MIGRATION_JOB_ID
  verb: verify
name: OPERATION_ID

To see if your operation is successful, you can query the returned operation object, or check the status of the migration job:

• Use the gcloud database-migration migration-jobs describe command to view the status of the migration job.
• Use the gcloud database-migration migration-jobs describe with the OPERATION_ID to see the status of the operation itself.

Start the migration job

Start the migration job by running the gcloud database-migration migration-jobs start command.

Before using any of the command data below, make the following replacements:

• MIGRATION_JOB_ID with your migration job identifier.

  If you don't know the identifier, you can use the gcloud database-migration migration-jobs list command to list all migration jobs in a given region and view their identifiers.

• REGION with the identifier of the region where your connection profile is saved.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs \
start MIGRATION_JOB_ID \
  --region=REGION

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs `
start MIGRATION_JOB_ID `
  --region=REGION

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs ^
start MIGRATION_JOB_ID ^
  --region=REGION

Result

The action is performed in an asynchronous manner. As such, this command returns an Operation entity that represents a long-running operation:

done: false
metadata:
  '@type': type.googleapis.com/google.cloud.clouddms.v1.OperationMetadata
  apiVersion: v1
  createTime: '2024-02-20T12:20:24.493106418Z'
  requestedCancellation: false
  target: MIGRATION_JOB_ID
  verb: start
name: OPERATION_ID

To see if your operation is successful, you can query the returned operation object, or check the status of the migration job:

• Use the gcloud database-migration migration-jobs describe command to view the status of the migration job.
• Use the gcloud database-migration migration-jobs describe with the OPERATION_ID to see the status of the operation itself.

Promote the migration job

Once the migration reaches the Change Data Capture (CDC) phase, you can promote the destination database instance from a read replica to a standalone instance. Run the gcloud database-migration migration-jobs promote command:

Before using any of the command data below, make the following replacements:

• MIGRATION_JOB_ID with your migration job identifier.

  If you don't know the identifier, you can use the gcloud database-migration migration-jobs list command to list all migration jobs in a given region and view their identifiers.

• REGION with the identifier of the region where your connection profile is saved.

Execute the following command:

Linux, macOS, or Cloud Shell

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs \
promote MIGRATION_JOB_ID \
  --region=REGION

Windows (PowerShell)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs `
promote MIGRATION_JOB_ID `
  --region=REGION

Windows (cmd.exe)

Note: Ensure you have initialized the Google Cloud CLI with authentication and a project by running either gcloud init; or gcloud auth login and gcloud config set project.

gcloud database-migration migration-jobs ^
promote MIGRATION_JOB_ID ^
  --region=REGION

Result

The action is performed in an asynchronous manner. As such, this command returns an Operation entity that represents a long-running operation:

done: false
metadata:
  '@type': type.googleapis.com/google.cloud.clouddms.v1.OperationMetadata
  apiVersion: v1
  createTime: '2024-02-20T12:20:24.493106418Z'
  requestedCancellation: false
  target: MIGRATION_JOB_ID
  verb: start
name: OPERATION_ID

To see if your operation is successful, you can query the returned operation object, or check the status of the migration job:

• Use the gcloud database-migration migration-jobs describe command to view the status of the migration job.
• Use the gcloud database-migration migration-jobs describe with the OPERATION_ID to see the status of the operation itself.

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