wtop - Google Code
wtop is like "top" for your webserver. How many searches or signups are happening per second? What is the response time histogram for your static files? wtop shows you at a glance.
RightScale: Launch scalable Amazon EC2 instances
RightScale's automated cloud computing management system helps you create scalable web applications that run on Amazon's Elastic Compute Cloud. Our advanced auto-scaling and load balancing features ensure your site's uptime and reliability. The RightScale Dashboard makes it easy to setup, launch, and monitor all of your EC2 and AWS activities.
scalr - Google Code
Scalr is a fully redundant, self-curing and self-scaling hosting environment utilizing Amazon's EC2.
It allows you to create server farms through a web-based interface using prebuilt AMI's for load balancers (pound or nginx), app servers (apache, others), databases (mysql master-slave, others), and a generic AMI to build on top of.
The health of the farm is continuously monitored and maintained. When the Load Average on a type of node goes above a configurable threshold a new node is inserted into the farm to spread the load and the cluster is reconfigured. When a node crashes a new machine of that type is inserted into the farm to replace it.