# Prerequisites for automated instance configuration
<a name="auto-config-pre-reqs"></a>

For AMS Advanced customers who deploy instances with Change Management, the following prerequisites must be met: 
+ The SSM Agent is installed, and in a managed state.
+ The instance is tagged as a managed instance. (The `aws:cloudformation:stack-name` tag has a value starting with `stack-` or `sc-`.)

If the SSM Agent is not already installed on your instance, you can install it using the AMS SSM Agent auto installation feature. For more information, see [SSM Agent automatic installation](ssm-agent-auto-install.md).

Or, you can install the SSM Agent manually. For more information, see the following:
+ Linux: [Manually install SSM Agent on EC2 instances for Linux - AWS Systems Manager](https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-manual-agent-install.html)
+ Windows: [Manually install SSM Agent on EC2 instances for Windows Server - AWS Systems Manager](https://docs.aws.amazon.com/systems-manager/latest/userguide/sysman-install-win.html)

For more information on SSM agent, see the AWS documentation [Working with SSM Agent](https://docs.aws.amazon.com/systems-manager/latest/userguide/ssm-agent.html).