How are spot instances represented in cloud carbon footprint?

[Chris Adams]

Hi folks.

Where would I look to learn how spot instances from say... AWS are handled in CCF?

I'm curious if there has been any discussion about how spot instances ought to be represented in Cloud Carbon Footprint, and I've looked in the following places:

- the github project discussions

- the github project issues

- the project codebase itself

- this google group

On one had, they're a use of spare capacity that is extra oversubscribed and can be shut off at short notice, so theoretically, you wouldn't need to provision much physical hardware to offer a given quantity of them.

Based on this I might expect that emission factor for the hourly impact would be lower than an on-demand instance. We see this represented in the cost benefits listed on the AWS spot page:

https://aws.amazon.com/ec2/spot/ - upto 90% savings vs purchasing on-demand capacity

And this video goes into an interesting set up with Skyscanner too:

https://hostingjournalist.com/video/skyscanner-building-highly-available-multi-region-kubernetes-clusters-on-100-amazon-ec2-spot

On the other hand, I'm not aware of how CCF represents oversubscription for on-demand instances anyway, so this might already be addressed, or explicitly kept out of scope.

I'd welcome pointers, as the use of spot instances is mentioned as a valid technique in the O'reilly Building Green Software book, and it would be great to point to some validated numbers either way.

Thanks

Chris Adams

Green Web Foundation