Amazon CloudWatch has matured and now is available with a Freemium tier for monitoring your EC2 instance at no charge.

Amazon Cloudwatch allows you to monitor:

  • CPU Load
  • Disk Input / Ouput
  • Network Input / Output

For your Amazon EC2 instances.   The data is collected every five minutes and stored for two weeks.

In true essence of a Freemium model you can then upgrade to a more detailed monitoring for .0015 / per hour per instance.

If you are looking to take advantage of truly auto-scaling your Amazon EC2 infrastructure you need to start getting familiar with how Amazon CloudWatch works