ApsaraDB RDS：Migrate the data of a PostgreSQL instance that has a public IP address to an ApsaraDB RDS for PostgreSQL instance

Step 1: Configure an Internet NAT gateway and associate an EIP with the Internet NAT gateway

This step describes how to associate a public IP address with the VPC of your RDS instance. After a public IP address is associated, your RDS instance can access a self-managed PostgreSQL instance that has a public IP address or a PostgreSQL instance of a third-party cloud service provider.

1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

2. In the left-side navigation pane, click Database Connection. In the Database Connection section of the page that appears, click the VPC link to the right of the Network Type parameter.

   

3. In the VPC console, click the Resources tab. In the Access to Internet section, click Create Now.

   

4. On the Internet NAT Gateway page, configure the following parameters and retain the default values for the parameters that are not described in the following table.

   Parameter	Description	Example
   EIP	If an EIP has been associated with the VPC, set this parameter to Select EIP. In this topic, Purchase EIP is selected.	Purchase EIP
   Maximum Bandwidth	Specify the maximum bandwidth value based on your business requirements. To facilitate the cloud migration, you can set this parameter to the maximum value to prevent slow cloud migration issues due to bandwidth limits.	200Mbps

5. Click Buy Now.

6. Confirm the parameter settings, read and select Terms of Service, and then click Confirm.

   If the page that is shown in the following figure appears, the Internet NAT gateway is created, an EIP is associated with the Internet NAT gateway, and SNAT entries are created for the Internet NAT gateway.

   

7. Click the resource ID of the EIP. On the Instance Information tab of the EIP, view the public IP address.

   

Step 2: Configure the self-managed PostgreSQL instance or the PostgreSQL instance of the third-party cloud service provider

Step 3: Perform a cloud migration assessment

1. Log on to the ApsaraDB RDS console and go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the instance ID.

2. In the left-side navigation pane, click Cloud Migration/DR Construction. On the page that appears, click the Feasibility assessment tab.

3. In the Configure Scenario and Source Type step of the configuration wizard, select Migration to Cloud for Scenario and Self-managed Instance or Other Instance for Source. Then, click Next.

4. In the Configure Destination Instance step of the configuration wizard, click Next.

5. In the Configure Source Instance step of the configuration wizard, select all listed items and click Next. Before you start the cloud migration, you must complete the preparations that are described in the listed items.

6. In the Start Feasibility Assessment step of the configuration wizard, configure the information about the self-managed PostgreSQL instance.

   Parameter	Description
   Migration Task Name	The system automatically generates a name for the cloud migration task. You do not need to modify the generated name.
   Source VPC/DNS IP	If the source instance is a self-managed PostgreSQL instance that has a public IP address, set this parameter to the public IP address of the server on which the self-managed PostgreSQL instance is deployed. If the source instance is a PostgreSQL instance of a third-party cloud service provider, set this parameter to the public endpoint of the PostgreSQL instance.
   Port of Source Instance	If the source instance is a self-managed PostgreSQL instance that has a public IP address, you can run the netstat -a | grep PGSQL command to view the port. If the source instance is a PostgreSQL instance of a third-party cloud service provider, you can go to the console of the third-party cloud service provider to view the port.
   Username	The username and password that are created for the cloud migration task in Step 2.
   Password

7. Click Create Feasibility Assessment Task.

   After the cloud migration assessment is complete, you can view the status of the cloud migration assessment task in Migration to Cloud section of the Feasibility assessment tab.

   • If the value in the Status column of the feasibility assessment task is Successful, you can start the cloud migration.

   • If the value in the Status column of the feasibility assessment task is Failed, you can click View Report in the Actions column to view and handle the reported errors. For more information about common errors, see Introduction to cloud migration assessment reports.

     Note

     Third-party cloud service providers may use self-developed or custom PostgreSQL extensions. If an extension incompatibility issue occurs during the migration, you can submit a ticket.

   After you handle the reported errors, you can click Re-assess in the Actions column to run the cloud migration assessment task again.

Step 4: Start the cloud migration

1. Go to the Instances page. In the top navigation bar, select the region in which the RDS instance resides. Then, find the RDS instance and click the ID of the instance.

2. In the left-side navigation pane, click Cloud Migration/DR Construction. On the page that appears, click the Migration to Cloud tab. On the tab that appears, click Create Cloud Migration Task.

3. In the Create Cloud Migration Task dialog box, select the migration assessment task whose status indicates a success in Step 3 from the Associated Assessment Task drop-down list.

   After you select a migration assessment task from the Associated Assessment Task drop-down list, the system automatically obtains the values of the required parameters.

4. Click Initiate Migration to Cloud. The system automatically starts the cloud migration task.

   Warning

   During the cloud migration, make sure that the PostgreSQL instance can be accessed. Do not perform operations such as restart. If transient connections or switchovers that are required to achieve high availability occur during the cloud migration, the cloud migration fails.

5. Switch the workloads.

   1. Click the link in the Cloud Migration Phase column to view the progress of the cloud migration task.

   2. When the cloud migration task enters the phase of Incremental Data Synchronization, click Switchover in the Actions column of the cloud migration task to switch the workloads of the PostgreSQL instance to the RDS instance.

   3. In the Switchover dialog box, configure the PostgreSQL instance to process only read requests. Alternatively, stop the connected application from writing data to the PostgreSQL instance.

      You can configure the PostgreSQL instance to process only read requests.

      -- Configure the PostgreSQL instance to process only read requests.
      ALTER SYSTEM SET default_transaction_read_only=on;
      
      -- Reload the parameter configuration for the modification to take effect.
      SELECT pg_reload_conf();
      
      -- Terminate all existing sessions.
      SELECT pg_terminate_backend(pid) FROM pg_stat_activity 
      WHERE usename not in ('replicator', 'monitor', 'pgsql', 'aurora') AND pid != pg_backend_pid();

   4. Select all check boxes and click Switch Now. Then, wait until the cloud migration is complete.