Amazon has promised load balancing, server monitoring and auto-scaling support for EC2 instances for quite some time. This morning, they delivered. This morning Amazon Web Services announced the following new features for EC2 instances:

Amazon CloudWatch - CPU, disk, and network monitoring for EC2 instances.

Auto-Scaling - A system to dynamically add or subtract EC2 instances from a pool based on status in Amazon CloudWatch.

Elastic Load Balancing - You can now automatically balance load between multiple EC2 instances.

The costs seem pretty reasonable. They're charging about 1.5 pennies per instance-hour for CloudWatch (which includes the scaling features), and charging 2.5 pennies per hour for load balancing.

I'll be testing out the load balancing features right away. I have a few dedicated HAProxy instances that could be replaced by this service. I'm estimating its going be about $54/month cheaper to use Elastic Load Balancing over a dedicated HAProxy machine.