Update instance type of EC2 running SQL server

AWS has also created System Manager Automation workflows to assist with the upgrade of SQL Server, the below documentation will provide more information: https://docs.aws.amazon.com/systems-manager-automation-runbooks/latest/userguide/automation-awsec2-CloneInstanceAndUpgradeSQLServer.html

Upgrading SQL Server and changing the AWS instance type generally doesn’t cause issues, as SQL Server doesn’t typically expect certain processor types or numbers. However, post-upgrade tuning may be required.

In particular, you need to stop the instance to prevent new connections during the upgrade. Change the instance type to i3.xlarge using AWS Management Console, AWS CLI, or AWS SDKs and start the instance after the instance type has been changed.

At the end Upgrade SQL Server to 2017 using the SQL Server Installation Center. Remember to backup all databases before starting the upgrade and ensure your system meets the hardware and software requirements for SQL Server 2017