I would like to share a series of post explaining the main services that AWS offered right now, just the main ones because the number of services grow day by day. We will see just a simple description of the main features of each service.
Amazon Elastic Compute Cloud (EC2)
EC2 is in AWS the same than a VM in Virtualization world. You can configure the capacity of your EC2 from AWS console in a very simple and easy way. Changing CPU, RAM, etc. in just some minutes. You will pay only for you use.
EC2 CPU is measured in ECUs, 1 ECU = CPU capacity of 1.0-1.2 GHz 2007 Opteron or 2007 Xeon processor. You can find a depth explanation on this link.
AutoScaling
This service enables you to scale your EC2 capacity horizontally, adding or removing additional EC2s when conditions specified by you are complied. It works with Amazon CloudWatch (AWS monitoring tool) to enable that. It doesn’t have any additional cost, you will pay just for the EC2s that were running, not for AutoScaling service.
AutoScaling just exist in a Region, but it could be implemented in all Availability Zones of this Region. The first step is to create an AutoScaling Group, then we have to create an AutoScaling Policy (based, for example, in the work load supported by CPU or RAM) and apply it to the Group created before.
We can use AutoScaling with Scheduling Policies too. For example, we can establish that at a concrete time I want 2 additional server in my web front-end, and at other time, I want to remove them.
Angel Perez Palacios 