Server Migration Center:Cross-zone ECS instance migration

Scenarios

• Change the instance type of an ECS instance

  If the current configurations of your ECS instance cannot meet your business requirements and the required instance type is sold out in the current zone, you can change the instance type within the same instance family while migrating the ECS instance across zones.

• Change the zone of an ECS instance

  You can deploy your application on ECS instances across different zones in a region to ensure that when a zone fails, services can be quickly switched to another zone to continue running. This improves the overall availability and stability of your system.

Limits

• Preemptible instances are not supported.

• You must change the instance type of an ECS instance within the same instance family. For more information about instance families, see Overview of instance families.

  Note

  If you want to change the instance type of an ECS instance to a different family across zones, we recommend that you perform a cross-zone migration first, and then change the instance type. For more information, see Upgrade the instance types of subscription instances or Change the instance type of a pay-as-you-go instance.

• The following instance families do not support instance type changes across zones:

  • Heterogeneous computing instance families

  • ECS Bare Metal Instance families

  • Super Computing Cluster (SCC) instance families

  • u1, universal instance family

  • e, economy instance family

  • x86-based instance families

    • Big data instance families

    • Instance families with local SSDs

    • Security-enhanced instance families

  • Instance families of the eighth generation, including g8ise, g8a, g8i, g8ae, g8y, c8a, c8i, c8ae, c8y, r8a, r8i, r8ae, and r8y

Migration impacts

Billing

• When you migrate an ECS instance, if you do not change its instance type, no fee changes are involved.

• Otherwise, fees are changed based on the following rules:

  • If you downgrade the instance type of a subscription ECS instance, the instance type downgrade may result in a refund. The refund amount is calculated by using the following formula: Refund amount = Remaining amount of the configuration price before the downgrade - Price of the new configurations.

    Important

    A monthly quota is enforced on instance type downgrades of subscription instances. The monthly quota is determined based on your historical consumption. The actual quota is displayed in the ECS console. If the monthly downgrade quota is exhausted, you cannot downgrade instance types until the quota is reset on the first day of the next month.

  • If you upgrade the instance type of a subscription ECS instance, you must pay for the price difference between the original instance type and the new instance type for the remainder of the current billing cycle. Actual fees are displayed in the ECS console.

  • If you change the instance type of a pay-as-you go ECS instance, you are charged based on the new instance type.

Procedure

1. Log on to the SMC console.

2. In the left-side navigation pane, choose Cloud Migration > Cross-zone Migration.

3. Click Start Migration or Migrate Now.

4. In the Cross-zone Instance Type Change dialog box, select the ECS instance from which you want to migrate data, and click Configure Parameters.

5. After you configure the parameters, click OK.

   The following table describes the parameters.

   Parameter	Description
   Migration Job Type	By default, ECS Instance Migration is selected. The setting cannot be changed.
   Region	The region where the ECS instance is located.
   Preferred Destination Zone	Select the zone to which you want to migrate the instances.
   Preferred Network Settings	Select a destination vSwitch. After the instance is migrated, a new private IP address that belongs to the CIDR block of the vSwitch is randomly assigned to the instance. Important After the instance type of an instance is changed across zones, the original private IP address of the instance is not retained. Make sure that applications deployed on the instance do not depend on the original private IP address. You can modify the private IP address after the migration is complete. For more information, see Change the primary private IPv4 address for an existing ECS instance.
   Instance Type	Specify whether to change the instance types based on your business requirements. Valid values: Use Current Instance Type: Do not change the instance types. Change Instance Type: Change the instance types. For information about the instance families that support instance type changes across zones and other limits on instance type changes, see Limits. Important You can change an instance type only to another type within the same instance family.
   Preferred New Instance Type	Select a destination instance type. Note This parameter is displayed only if you select Change Instance Type.
   Configuration-changed Instances to Be Migrated	Display information about the selected Instance ID/Name, Destination Zone, Instance Type, and Destination vSwitch.
   Note	Select I have backed up data.

6. In the dialog box that appears, click Pay to complete the payment as prsompted.

Verify the migration result

• The migration is successful if the migration job enters the Completed state.

  After the cross-zone migration job is complete, perform the following operations to check the migration result:

  1. Click View Destination Instance in the Actions column of a migration source.

  2. On the Instance Details tab, view the Zone and Instance Type parameters of the migrated ECS instance.

• The migration failed if the migration job enters the InError state.

  In this case, you need to perform the following operations:

  1. Click Troubleshoot Errors in the Actions column and fix the failure based on the error code and error message. For more information, see FAQ about Server Migration Center (SMC) and Troubleshooting.

  2. On the Migration Jobs page, click Retry Migration Job.

     The migration job resumes from the point where it was suspended.

FAQ

During cross-zone migration, a prompt as shown in the following figure is displayed.

To troubleshoot the issue, perform the following operations:

1. Check for Workbench private links.

   Log on to the Workbench console, choose Instance > Private Links, and check whether there is a private link for the ECS instance.

   • If yes, click Release Link and proceed to the next step.

     

   • If no, proceed to the next step.

2. Check whether there is a custom route entry whose next hop is an ECS instance.

   Log on to the VPC Console and check whether there is a custom route entry whose next hop is an ECS instance.

   • If yes, delete the custom route entry and proceed to the next step.

     

   • If no, proceed to the next step.

3. Check whether there is a DTS migration task whose source database is Self-managed Database on ECS.

   Log on to the DTS console and check whether there is a DTS migration task whose source database is Self-managed Database on ECS.

   • If yes, delete the migration task and proceed to the next step.

     Important

     Before deleting a DTS task, make sure that the data transfer is complete and backups are made.

   • If no, proceed to the next step.

4. Check for VPC advanced features.

   Log on to the VPC Console and check whether there are VPC advanced features enabled. If yes, delete the advanced features before proceeding with the operations in this topic. For more information about VPC advanced features, see Advanced VPC features.