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I started with a 64 bit version of Ubuntu 9.10 Karmic server edition. (using a micro instance on Amazon EC2, costing less than $0.01 per hour)

I added GNOME desktop to it and NX server.

I re-bundled the instance into a new AMI.

Now upon trying to start another instance of my freshly created AMI. I am unable to select a "micro"/cheap server format.

What have I done wrong? What triggered this limitation?

Is Amazon really smart enough to know which AMIs will work on which Servers? I had it running fine on a micro server while I re-bundled it..?

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up vote 2 down vote accepted

Micro instances must be EBS backed, they cannot be AMI backed. You will convert it.

Micro Instance 613 MB of memory, Up to 2 EC2 Compute Units (for short periodic bursts), EBS storage only, 32-bit or 64-bit platform"

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Hrmmm so it is... My instance was EBS backed to begin with, why when I re-bundle it does it become instance/AMI backed??? – darkAsPitch Mar 10 '11 at 4:16
The bundling process creates the AMI... if it was EBS backed to begin with you didn't need to rebundle at all, since EBS volumes are long lived. You can snapshot a EBS volume to use it as a starting template for new instances, should you choose. – mfarver Mar 10 '11 at 4:37

I'm not sure why you wouldn't be able to launch your AMI in a new micro instance but I think there's a bit of confusion here. Just to be clear, AMI and EBS are not two different options for backing instances. EBS and S3 are the two options for backing AMIs (from documentation located here under Using Amazon EC2 -> Using AMIs -> AMI Basics). Your AMI is very likely still backed by EBS and, therefore, acceptable for use with a micro instance. Something else must be going on.

All AMIs are categorized as either backed by Amazon EBS or backed by Amazon S3. The former means that the root device is an Amazon EBS snapshot and appears as an Amazon EBS volume when an instance is launched from the AMI. The latter means that the root device is stored in Amazon S3 and appears as local storage when an instance is launched from the AMI.

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EBS and AMI are very different. An instance started from AMI (loaded from S3) has no permanent storage. If it is shutdown and restarted the "disk" will revert back to the state it was in when the AMI-bundle was made. A EBS is permanent storage, an image booting from a EBS volume will maintain state when restarted. – mfarver Mar 10 '11 at 19:59
Please take a look at the page I linked to and referenced. AMI just means Amazon Machine Image, it can be backed by either Elastic Block Storage (EBS) or Simple Storage Service (S3). The page I referenced breaks down the differences between the two options in detail. You are right that they are very different, but they are both AMIs. – MKing Mar 10 '11 at 20:29

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