Schedule the change of an EC2 instance type

Question

Is there a way to pre-configure an instance type change for an EC2 instance so it happens automatically after the next reboot? Kind of like changes to RDS can set to be executed at the next maintenance interval. The instances are not in an Autoscaler group and they're all one-of-a-kind, various types / AMIs / OSs and whatnot... a CLI option would be amazing, but if I have to click through all of them, so be it.

Thanks, Marc

Thanks,
Marc

Raphael · Accepted Answer

I would consider using an AWS Systems Manager (SSM) Automation to call the EC2 API and update the instance type. For scheduling, you could use EventBridge Scheduler with a one-time schedule (it also supports a flexible window). SSM also has a few native scheduling options.

You can use the AWS provided AWS-ResizeInstance automation, or copy it and create your own one. The SSM document will use the aws:executeAwsApi action to call ModifyInstanceAttribute. The main benefit using SSM is that you can ensure it stops the instance, modifies starts etc. and check for errors. Again, the AWS provided one is a good start and might suffice.

You can use the AWS provided [`AWS-ResizeInstance`](https://docs.aws.amazon.com/systems-manager-automation-runbooks/latest/userguide/automation-aws-resizeinstance.html) automation, or copy it and create your own one. The SSM document will use the [`aws:executeAwsApi`](https://docs.aws.amazon.com/systems-manager/latest/userguide/automation-action-executeAwsApi.html) action to call [`ModifyInstanceAttribute`](https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_ModifyInstanceAttribute.html). The main benefit using SSM is that you can ensure it stops the instance, modifies starts etc. and check for errors. Again, the AWS provided one is a good start and might suffice.

Schedule the change of an EC2 instance type

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