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Curious about the underpinnings of this.

With traditionally data center hypervisors you can create virtual disk and virtual machines. You can create a virtual machine without a virtual disk. The virtual machine is OS independent.

Is there an aws analogue to this? EBS volumes are of course virtual disks but amis are the whole shebang- the vm AND the storage.

Looks like there is no way to create a blank ami and attach a volume later.

Why is this? Is this because amazon is using a different hypervisor for different platforms (hyper-v) so it needs to know what the OS is before it can create a VM for you?

What if I launch some linux ami, then detach the root volume and attach an EBS volume with windows on it? Will that work and be supported by amazon?

red888
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An AMI is primarily a disk image. There is some metadata about the image and EC2 details.

Without a disk you have compute with no operating system or tasks, which is fairly pointless.

What exactly are you trying to achieve?

Tim
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  • Just curious about how this works. Is there any info about the actual VM? I know aws uses XEN but do they also, use hyper-v? I cant launch a new ami with an existing volume for instance, I need to launch an ami with its own root volume then detach that and attach an exiting one. Also, what happens if I attach a windows volume to the root of a linux ami or vice versa? – red888 Apr 08 '18 at 22:35
  • I don't know sorry. That's another question, and one that is probably too wide / vague for SF. – Tim Apr 08 '18 at 23:27