Tutorial: Migrate offline from an Azure VM or an on-premises PostgreSQL server to Azure Database for PostgreSQL with the migration service

This article guides you using the Azure portal to migrate your PostgreSQL database from an Azure VM or an on-premises PostgreSQL server to an Azure Database for PostgreSQL. The Azure portal allows you to perform various tasks, including database migration. Following the steps outlined in this tutorial, you can seamlessly transfer your database to Azure and take advantage of its powerful features and scalability.

Configure the migration task

The migration service comes with a simple, wizard-based experience on the Azure portal.

1. Open your web browser and go to the portal. Enter your credentials to sign in. The default view is your service dashboard.

2. Go to your Azure Database for the PostgreSQL flexible server.

3. In the Overview tab of the flexible server, on the left menu, scroll down to Migration and select it.

   

4. Select the Create button to migrate to a flexible server from on-premises or Azure VMs.

   Note

   The first time you use the migration service, an empty grid appears with a prompt to begin your first migration.

   If migrations to your flexible server target have already been created, the grid now contains information about attempted migrations.

5. Select the Create button to go through a wizard-based series of tabs to perform a migration.

   

Setup

The user needs to provide multiple details related to the migration, like the migration name, source server type, option, and mode.

• Migration name is the unique identifier for each migration to this Flexible Server target. This field accepts only alphanumeric characters and doesn't accept any special characters except a hyphen (-). The name can't start with a hyphen and should be unique for a target server. No two migrations to the same Flexible Server target can have the same name.

• Source Server Type - Depending on your PostgreSQL source, you can select Azure Database for PostgreSQL Single Server, Azure VM, or on-premises.

• Migration Option - Allows you to perform validations before triggering a migration. You can pick any of the following options

  • Validate - Checks your server and database readiness for migration to the target.
  • Migrate - Skips validations and starts migrations.
  • Validate and Migrate—Performs validation before triggering a migration. If there are no validation failures, the migration is triggered.

Choosing the Validate or Validate and Migrate option is always a good practice for performing premigration validations before running the migration.

To learn more about the premigration validation, visit premigration.

• Migration mode allows you to pick the mode for the migration. Offline is the default option.

Select the Next: Connect to source button.

Runtime Server

The Migration Runtime Server is a specialized feature within the migration service in Azure Database for PostgreSQL, designed to act as an intermediary server during migration. It's a separate Azure Database for PostgreSQL - Flexible Server instance that isn't the target server but is used to facilitate the migration of databases from a source environment that is only accessible via a private network.

For more information about the Runtime Server, visit the Migration Runtime Server.

Connect to source

The Connect to Source tab prompts you to give details related to the source selected in the Setup Tab, which is the source of the databases.

• Server Name - Provide the Hostname or the IP address of the source PostgreSQL instance
• Port - Port number of the Source server
• Server admin login name - Username of the source PostgreSQL server
• Password - Password of the source PostgreSQL server
• SSL Mode - Supported values are preferred and required. When the SSL at the source PostgreSQL server is OFF, use the SSLMODE=prefer. If the SSL at the source server is ON, use the SSLMODE=require. SSL values can be determined in postgresql.conf file.
• Test Connection-Performs the connectivity test between the target and source. Once the connection is successful, users can proceed to the next step; they need to identify the networking issues between the target and source and verify the username/password for the source. Establishing a test connection takes a few minutes.

After the successful test connection, select the Next: Select Migration target button.

Select migration target

The select migration target tab displays metadata for the Flexible Server target, such as the subscription name, resource group, server name, location, and PostgreSQL version.

• Admin username - Admin username of the target PostgreSQL server
• Password - Password of the target PostgreSQL server
• Custom FQDN/IP (Optional): The custom FQDN/IP field is optional and can be used when the target is behind a custom DNS server or has custom DNS namespaces, making it accessible only via specific FQDNs or IP addresses. For example, this could include entries like flexibleserver.example.com, 198.1.0.2, or a PostgreSQL FQDN such as flexibleserver.postgres.database.chinacloudapi.cn, if the custom DNS server contains the DNS zone postgres.database.chinacloudapi.cn or forwards queries for this zone to 168.63.129.16, where the FQDN is resolved in the Azure public or private DNS zone.
• Test Connection - Performs the connectivity test between target and source. Once the connection is successful, users can proceed with the next step. Otherwise, we need to identify the networking issues between the target and the source and verify the target's username/password. Test connection takes a few minutes to establish a connection between the target and source

After the successful test connection, select the Next: Select Database(s) for Migration

Select databases for migration

Under the Selected database for migration tab, you can choose a list of user databases to migrate from your source PostgreSQL server.

After selecting the databases, select the Next: Summary.

Summary

The Summary tab summarizes all the source and target details for creating the validation or migration. Review the details and select the Start Validation and Migration button.

Monitor the migration

After you select the Start Validation and Migration button, a notification appears in a few seconds to say that the validation or migration creation is successful. You're automatically redirected to the flexible server's Migration page. The entry is in the InProgress state and PerformingPreRequisiteSteps substate. The workflow takes 2-3 minutes to set up the migration infrastructure and check network connections.

The grid that displays the migrations has these columns: Name, Status, Migration mode, Migration type, Source server, Source server type, Databases, **Duration, and Start time. The entries are displayed in the descending order of the start time, with the most recent entry on the top. You can use the refresh button to refresh the status of the validation or migration run.

Migration details

Select the migration name in the grid to see the associated details.

In the Setup tab, we have selected the migration option as Validate and Migrate. In this scenario, validations are performed first before migration starts. After the PerformingPreRequisiteSteps substrate is completed, the workflow moves into the substrate of Validation in Progress.

• If validation has errors, the migration moves into a Failed state.

• If validation is complete without error, the migration starts, and the workflow moves into the substate of Migrating Data.

Validation details are available at the instance and database level.

• Validation at Instance level
  • Contains validation related to the connectivity check, source version, that is, PostgreSQL version >= 9.5, and server parameter check, whether the extensions are enabled in the server parameters of the Azure Database for PostgreSQL-flexible server.
• Validation at Database level
  • It contains validation of the individual databases related to extensions and collations support in Azure Database for PostgreSQL, a flexible server.

You can see the validation and the migration status under the migration details page.

Some possible migration states:

Migration states

Migration substates

Validation substates

Cancel the migration using the portal

You can cancel any ongoing validations or migrations. The workflow must be in the InProgress state to be canceled. You can't cancel a validation or migration in the Succeeded or Failed state.

• Canceling a validation stops further validation activity, and the validation moves to a Canceled state.
• Canceling a migration stops further migration activity on your target server and moves to a Canceled state. The cancel action returns all changes the migration service makes on your target server.

This article explores using the Azure CLI to migrate your PostgreSQL database from an Azure virtual machine or an on-premises PostgreSQL instance to an Azure Database for PostgreSQL. The Azure CLI provides a powerful and flexible command-line interface that allows you to perform various tasks, including database migration. Following the steps outlined in this article, you can seamlessly transfer your database to Azure and take advantage of its powerful features and scalability.

To learn more about Azure CLI with the migration service, visit How to set up Azure CLI for the migration service.

Once the CLI is installed, open the command prompt and log into your Azure account using the below command.

az login

Configure the migration task

To begin the migration, create a JSON file with the migration details. The JSON file contains the following information:

• Edit the below placeholders << >> in the JSON lines and store them in the local machine as <<filename>>.json where the CLI is being invoked. In this tutorial, we have saved the file in C:\migration-CLI\migration_body.json

{
"properties": {
"SourceDBServerResourceId": "<<source hostname or IP address>>:<<port>>@<<username>>",
        "SecretParameters": {
            "AdminCredentials": {
                "SourceServerPassword": "<<Source Password>>",
                "TargetServerPassword": "<<Target Password>>"
            },
			"targetServerUserName": "<<Target username>>"
        },
        "DBsToMigrate": "<<comma separated list of databases in a array like - ["ticketdb","timedb","inventorydb"]>>",
        "OverwriteDBsInTarget": "true",
        "sourceType": "OnPremises",
        "sslMode": "Prefer"
    }
}

• Run the following command to check if any migrations are running. The migration name is unique across the migrations within the Azure Database for PostgreSQL flexible server target.

  az postgres flexible-server migration list --subscription 11111111-1111-1111-1111-111111111111 --resource-group my-learning-rg --name myflexibleserver --filter All
  

• In the above steps, there are no migrations performed so we start with the new migration by running the following command

  az postgres flexible-server migration create --subscription 11111111-1111-1111-1111-111111111111 --resource-group my-learning-rg --name myflexibleserver --migration-name migration1 --migration-mode offline --migration-option ValidateAndMigrate --properties "C:\migration-cli\migration_body.json"
  

• Run the following command to initiate the migration status in the previous step. You can check the status of the migration by providing the migration name

  az postgres flexible-server migration show --subscription 11111111-1111-1111-1111-111111111111 --resource-group my-learning-rg --name myflexibleserver --migration-name migration1
  

• The status of the migration progress is shown in the Azure CLI.

• You can also see the status of the Azure Database for PostgreSQL flexible server in the Azure portal.

• You can cancel any ongoing migration attempts using the cancel command. This command stops the particular migration attempt and rolls back all changes on your target server. Here's the CLI command to delete a migration:

  az postgres flexible-server migration update cancel --subscription 11111111-1111-1111-1111-111111111111 --resource-group my-learning-rg --name myflexibleserver --migration-name migration1