ApsaraDB RDS:Migrate proxy nodes across zones

Prerequisites

• Your RDS instance meets the following requirements:

  • The RDS instance runs MySQL.

  • The RDS instance runs RDS High-availability Edition or RDS Cluster Edition.

  • The RDS instance uses cloud disks.

  • The database proxy feature is enabled for the RDS instance.

  • The RDS instance is in the Running state.

    Note

    Make sure that the primary RDS instance, its read-only RDS instances, and its proxy node are all in the Running state.

• The RDS instance uses endpoints of the virtual private cloud (VPC) network type. Cross-zone migration is not supported for a database proxy of the classic network type. For more information, see View and manage instance endpoints and ports.

Billing rules

You can migrate proxy nodes across zones free of charge.

Impacts

• When you migrate proxy nodes across zones, a transient connection that lasts for approximately 30 seconds occurs during the migration.

  • If your RDS instance runs RDS High-availability Edition, you can use the endpoint of the primary RDS instance or a read-only RDS instance to connect your application to the RDS instance. This helps prevent your workloads from being unaffected.

  • If your RDS instance runs RDS Cluster Edition, you can use the read/write endpoint, read-only endpoint, or direct node connection endpoint to connect your application to the RDS instance. This helps prevent your workloads from being unaffected.

  Note

  We recommend that you connect your application to the RDS instance by using the preceding endpoints and migrate proxy nodes across zones during off-peak hours.

• Make sure that your application is configured to automatically reconnect to your RDS instance.

  Note

  If your application is not configured to automatically reconnect to your RDS instance, manually reconnect your application to your RDS instance.

• The cross-zone migration causes changes to the virtual IP addresses (VIPs) of your RDS instance. We recommend that you use an endpoint rather than an IP address of your RDS instance to connect your application to your RDS instance.

• After the cross-zone migration, you must immediately delete the cached DNS records from the database client. If the database client runs on a Java virtual machine (JVM), we recommend that you set the time-to-live (TTL) in the JVM configuration to 60 seconds or less. This way, if the VIP that is bound to the in-use endpoint of your RDS instance changes, your application can query the related DNS records again to obtain the new VIP. Then, your application can connect to the new VIP.

  Note

  For more information about how to specify the TTL in the JVM configuration, see Class InetAddress.

• If the resource inventory in the zone to which you want to migrate proxy nodes is insufficient, the migration may fail.

• Cross-zone migration may cause the nearest access feature to become invalid.

  After the cross-zone migration, the new nearest zone can be accessed by default. The original nearest zone can no longer be accessed. If you change the zone of a proxy endpoint to a zone that is different from the default zone, the nearest access to the new zone fails. The following table describes example scenarios.

  Scenario	Original proxy node information			New proxy node information
  	Current zone of the proxy node	Proxy endpoint	Nearest access	New zone of the proxy node	Default zone of the proxy endpoint	New zone of the proxy endpoint	Nearest access
  Scenario 1: Zone A+Zone B to Zone A+Zone C	Zone A	Proxy endpoint a	Zone A	Zone A	Zone A	Zone A	Zone A
  						Zone C	Invalid
  	Zone B	Proxy endpoint b	Zone B	Zone C	Zone C	Zone C	Zone C
  						Zone D	Invalid
  Scenario 2: Zone A+Zone B to Zone C+Zone D	Zone A	Proxy endpoint a	Zone A	Zone C	Zone C	Zone C	Zone C
  						Zone E	Invalid
  	Zone B	Proxy endpoint b	Zone B	Zone D	Zone D	Zone D	Zone D
  						Zone E	Invalid

Procedure

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

2. In the left-side navigation pane, click Database Proxy and view the basic information about your database proxy.

3. Click Cross-zone Migration.

   Note

   If Cross-zone Migration is not displayed, you must check whether your RDS instance meets the prerequisites.

4. In the Cross-zone Migration of Database Proxy dialog box, view the zone and network information about the primary RDS instance and the database proxy. Configure the Destination Zone, Destination vSwitch, and Change Time parameters, and click OK.

   Important

   During the cross-zone migration, you cannot change the type and specifications of the database proxy.

5. Read the impacts of the cross-zone migration and click OK again.

Related operations

FAQ

• Does the cross-zone migration of proxy nodes affect the connection to my primary RDS instance?

  The cross-zone migration of proxy nodes affects your workloads only if you use a proxy endpoint to connect to your RDS instance. If your RDS instance runs RDS High-availability Edition and you use the endpoint of the primary RDS instance or a read-only RDS instance to connect your application to the RDS instance, your workloads remain unaffected. If your RDS instance runs RDS Cluster Edition and you use the read/write endpoint, read-only endpoint, or direct node connection endpoint to connect your application to the RDS instance, your workloads remain unaffected. We recommend that you connect your application to the RDS instance by using the preceding endpoints and migrate proxy nodes across zones during off-peak hours.

• What are the impacts of the cross-zone migration of proxy nodes?

  When you migrate proxy nodes across zones, a transient connection that lasts for approximately 30 seconds occurs during the migration. The duration of the interruption varies based on your business. We recommend that you use the endpoints that are not affected by the migration to connect to your RDS instance and migrate proxy nodes across zones during off-peak hours. For more information, see Impacts.