CODEWITHSUNDEEP
amazon-web-services
Amon
Amon

Reputation: 2951

How to use existing On-Demand instance in spot fleet?

I'm trying to reduce my expenses and want to start using AWS's spot pricing service. I'm completely new to it, but as I understand I can have instances running for certain amounts of time based on the price that will eventually stop running based on certain conditions. That's fine, I'm also aware you can have spot fleets, and in these fleets you can have an On-Demand instance for when the spot instance is interrupted.

I currently have a an On-Demand instance that hosts an ElasticBeanStalk application (it's an API), is there a way to use this instance inside the spot fleet so that when there's an available spot-instance it's servicing my EBS application then when the spot-instance is interrupted it just goes back to using my current On-Demand instance until another spot-instance is available?

Upvotes: 1

Views: 398

Answers (2)

njonn
njonn

Reputation: 1

There's a third-party solution called Spot.io that not only replaces the spot instance for an on-demand instance in a scenario like the one you describe but it has an algorithm that anticipates the interruption event and stands up an On-demand instance and has it ready before the interruption occurs.

Upvotes: 0

Marcin
Marcin

Reputation: 238199

Sadly, spot fleets don't work like this. If your spot instance gets terminated, no on-demand replacement is going to be created for you automatically. If it worked like this, everyone would be using spot instances in my view.

The on-demand portion of your spot fleet is separate from spot portion. This way your application will always run at minimum capacity (without spot). When spot is available, your spot instances will run along side your on-demand. This way you will have more computational power for cheap, which is very beneficial for any heavy processing application (e.g. batch image processing).

Details of how spot fleet and spot instances work are in How Spot Fleet works and How Spot Instances work docs.

Nevertheless, if you would like to have such replacement provisioned you would have to develop a custom solution for that.

Upvotes: 2

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