Amazon has introduced a new type of EC2 instance, called a Micro Instance. These start at $0.02/hour for Linux and $0.03/hour for Windows, come with 613 MB of allocated RAM, a low allocation of CPU, and a limited ability to burst CPU. They have no local storage by default, requiring you to boot from EBS.

613 MB is not a lot of RAM, since operating systems can be RAM pigs if you don’t pay attention to what you’re running in your baseline OS image. My guess is that people who are using micro instances are likely to want to use a JeOS stack if possible. I’d be suggesting FastScale as the tool for producing slimmed-down stacks, except they got bought out some months ago, and wrapped in with EMC Ionix into VMware’s vCenter Configuration Manager; I don’t know if they’ve got anything that builds EC2 stacks any longer.

Amazon has suggested that micro instances can be used for small tasks — monitoring, cron jobs, DNS, and other such things. To me, though, smaller instances are perfect for a lot of enterprise applications. Tons of enterprise apps are “paperwork apps” — fill in a form, kick off some process, be able to report on it later. They get very little traffic, and consolidating the myriad tertiary low-volume applications is one of the things that often drives the most attractive virtualization consolidation ratios. (People are reluctant to run multiple apps on a single OS instance, especially on Windows, due to stability issues, so being able to give each app its own VM is a popular solution.) I read micro instances as being part of Amazon’s play towards being more attractive to the enterprise, since tiny tertiary apps are a major use case for initial migration to the cloud. Smaller instances are also potentially attractive to the test/dev use case, though somewhat less so, since more speed can mean more efficient developers (fewer compiling excuses).

This is very price-competitive with the low end of Rackspace’s Cloud Servers ($0.015/hour for 256 MB and $0.03/hour for 512 MB RAM, Linux only). Rackspace wins on pure ease of use, if you’re just someone who needs a single virtual server, but Amazon’s much broader feature set is likely to win over those who are looking for more than a VPS on steroids. GoGrid has no competitive offering in this range. Terremark can be competitive in this space due to their ability to oversubscribe and do bursting, making its cloud very suitable for smaller-scale enterprise apps. And VirtuStream can also offer smaller allocations tailored to small-scale enterprise apps. So Amazon’s by no means alone in this segment — but it’s a positive move that rounds out their cloud offerings.