If you are automatically scaling your servers using Amazon Auto Scaling or some other automated method, you want to have the agent automatically installed and to have monitoring start automatically. How to do this depends on how you're controlling your servers.
Installing the agent
Use our official Puppet and Chef modules to automatically install the agent and register new servers through our API.
There are several unofficial playbooks created by customers.
Our agent installer script will download the agent and use our API to register the server for you.
Automatically setting up alerts
Using group alerts you can have new servers inherit alerts automatically.
You could also use our API to create alerts through your own code.
Removing servers when they shut down
Our API lets you query it to find servers based on their hostname, so you can then call the delete method to remove the server when it's terminated. This will stop all alerts and remove the server from your billing.