Troubleshooting launch errors - Application Migration Service

Troubleshooting launch errors

Do I need to recreate the entire launch template for every version?

When you save a new template version, it is tagged as the latest version. However, for a multitude of reasons, AWS Application Migration Service (AWS MGN) uses the version marked as the default for its purposes. So in order to actually have AWS MGN recognize the changes you make, you need to go into the template itself, and change the default version to the version you have just updated.

Create the new template version. The window after creating the new template pops up a success box.

Click the launch template in the box, and then click Actions and choose Set default version.

Finally, from the drop down menu, select the latest version, and then click Set as default version.

The AWS MGN console should refresh and reflect the changes after this.

Error - AccessDeniedException - Must be admin user

If you receive an AccessDeniedException error when attempting to log into AWS Application Migration Service (AWS MGN) for the first time and set up your replication settings template, it means that you are not the administrator of your AWS Account and therefore cannot initialize AWS MGN. You must be the Admin user of your AWS Account to initialize AWS MGN. Learn more about initializing MGN.

VPCIdNotSpecified error

The EC2 launch template does not automatically set a specific Subnet. As such, EC2 will attempt to launch in a Subnet within the default VPC. If you have removed your default VPC, EC2 will fail to launch any instance for which there is no valid Subnet specified. Ensure that you specify a subnet if that is the case, or AWS Application Migration Service instance launch will fail. You may see the VPCIdNotSpecified error if:

  • A default subnet/VPC is not selected in the EC2 launch template.

  • An incorrect target subnet is specified in the EC2 launch template.

  • the EC2 launch template with the correct subnet settings is not set as the default.

Could not take up-to-date snapshot. Launching from snapshot taken on...

When a test or cutover instance is launched, AWS Application Migration Service (AWS MGN) will attempt to create the latest consistent snapshot of the source server. AWS MGN will wait for all the snapshots to become available and once they are ready, will proceed with the launch workflow.

When you see this message during the launch of a test or cutover instance, it means that the snapshot creation timed out. AWS MGN will then use the latest successful snapshot for that particular source server for the launch. This message indicates that the target launch was successful but has the data from the timestamp specified in the message.

There are various causes for this timeout, including that the source server was not in Continuous Data Protection (CDP) mode or that there was backlog/lag.

You can check CloudTrail Event History for errors for CreateSnapshot and DescribeSnapshot API calls which may prevent EBS snapshots from being created within the timeout period.