This document discusses EC2 Spot Instances on AWS and how to programmatically determine optimal Spot Instance pricing using the Terraform module for AWS Spot Instances. It provides an overview of Spot Instances, how spot pricing works, strategies for allocation and resilience, and examples of using the Terraform module to get the current minimum and increased reliability spot prices across different instance types and availability zones.

1. Communit
y
AWS Community
How To Save Resources With the
Terraform Module for AWS Spot
Instances
Vladimir Cageyv Samoylov

2. AWS Community
Key Takeaway
- What is EC2 Spot Instances and how it works
- The true cost of Spot Instances
- How we could programmatically get the max-price value

3. A Christmas Story and Huge Demand
for EC2

4. AWS Community
A December Surprise: Double the Payment for
AWS Spot Instances

5. Amazon EC2 Spot Instances
Who are you?

6. AWS EC2 Spot Instance = Unused
EC2 at a low price
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances.html

7. Interrupt readiness

8. AWS Community
2 minute termination notice. EC2 meta-data and
EventBridge
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-instance-termination-
notices.html

9. AWS Community
The Fault Injection Simulator can simulate
termination notices
More info: https://aws.amazon.com/fis/

10. Resilience and Elasticity with EC2
Auto Scaling Group

11. Using different Instance Types and
AZs increases launch chances

12. Spot Instance Advisor
More info: https://aws.amazon.com/ec2/spot/instance-advisor/

13. AWS Community
Spot Instance Advisor. Example

14. Allocation strategies for Spot Instances
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ec2-fleet-allocation-
strategy.html

15. AWS Community
Allocation strategies for Spot Instances
- price-capacity-optimized !!!
- capacity-optimized
- lowest-price
More info: https://aws.amazon.com/blogs/compute/introducing-price-capacity-optimized-
allocation-strategy-for-ec2-spot-instances/

16. Resilience with Capacity rebalance.
Get new EC2 in advance.
More info: https://ec2spotworkshops.com/ec2-auto-scaling-with-multiple-instance-types-and-
purchase-options/spot_resilience.html

17. AWS Community
EC2 Autoscaling Capacity rebalance
More info: https://github.com/awslabs/ec2-spot-labs/tree/master/ec2-spot-interruption-handler

18. Spot Instance Pricing
How much will I have to pay?

19. AWS Community
Cost Explorer

20. AWS Community
Spot Instance data feed
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-data-feeds.html

21. Charge = Spot Price

22. Spot Instance pricing history
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-spot-instances-
history.html

23. AWS Community
Spot price history (example from docs)

24. AWS Community
Spot price history (December expectations)

25. Spot Max Price
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-requests.html#using-
spot-instances-request (step 10 in new console example)

26. What will happen if the Spot Max Price
is not specified?
More info: https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/spot-requests.html#using-
spot-instances-request (step 10 in new console example)

27. What next? No more Spot Instances?

28. AWS Community
AWS CLI: aws ec2 describe-spot-price-history
More info: https://awscli.amazonaws.com/v2/documentation/api/latest/reference/ec2/describe-
spot-price-history.html

29. AWS Community
AWS API: EC2 DescribeSpotPriceHistory
More info:
https://docs.aws.amazon.com/AWSEC2/latest/APIReference/API_DescribeSpotPriceHistory.html

30. AWS Community
Terraform Module: ec2-spot-price
More info: https://github.com/fivexl/terraform-aws-ec2-spot-price

31. AWS Community
Initial data
AZ Type r5.2xlarge r5d.2xlarge r5a.2xlarge
eu-central-1a 0.20 0.20 0.20
eu-central-1b 0.20 0.15 0.10
eu-central-1c 0.20 0.30 0.25
*These prices are not real prices for EC2 Spot Instance

32. AWS Community
Example: All Instance Types in all AZs with
increased reliability.
module "ec2_spot_price" {
source = "fivexl/ec2-spot-price/aws"
version = "2.0.0"
instance_types_list = ["r5.2xlarge", "r5d.2xlarge", "r5a.2xlarge"]
availability_zones_names_list = ["eu-central-1a", "eu-central-1b", "eu-central-1c"]
сustom_price_modifier = 1.1
}
output "spot_price_current_max_mod" {
value = module.ec2_spot_price.spot_price_current_max_mod
}
Result: 0.33

33. AWS Community
Example: Cheapest as possible
module "ec2_spot_price" {
source = "fivexl/ec2-spot-price/aws"
version = "2.0.0"
instance_types_list = ["r5.2xlarge", "r5d.2xlarge", "r5a.2xlarge"]
availability_zones_names_list = ["eu-central-1a", "eu-central-1b", "eu-central-1c"]
}
output "spot_price_current_max_mod" {
value = module.ec2_spot_price.spot_price_current_min
}
Result: 0.10

34. EC2 Spot Instances use cases

35. Thank you
Contacts:
● https://t.me/cageyv
● https://cageyv.dev/
● https://github.com/cageyv/
● https://www.linkedin.com/in/vladimirsamoylov
/
Useful links:
● https://github.com/fivexl/terraform-aws-ec2-
spot-price
● https://aws.amazon.com/ru/ec2/spot/instance-
advisor/
● https://ec2spotworkshops.com/
● https://github.com/awslabs/ec2-spot-labs/
● https://github.com/aws/aws-node-
termination-handler
● https://docs.aws.amazon.com/AmazonECS/late
st/developerguide/container-instance-
spot.html