Spot Instances for cost savings in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Spot Instances behavior

What happens to an AWS Spot Instance when the spot price exceeds your bid price?

A AWS sends a two-minute warning before terminating the instance.

B The instance is terminated immediately without warning.

C The instance is automatically converted to an On-Demand instance.

D The instance continues running until you manually stop it.

💡 Hint

Think about how AWS manages Spot Instances to allow graceful shutdown.

AWS Spot Instances receive a two-minute warning before termination when the spot price exceeds the bid or capacity is no longer available. This allows applications to save state or gracefully shut down.

❓ Architecture

intermediate

Designing fault-tolerant architecture with Spot Instances

You want to use Spot Instances to save costs but ensure your application remains highly available. Which architectural pattern best supports this goal?

A Deploy Spot Instances in a single Availability Zone to reduce complexity.

B Use only Spot Instances behind a load balancer with no fallback.

C Use Spot Instances with a fixed bid price and no scaling policies.

D Mix Spot Instances with On-Demand Instances in an Auto Scaling group.

💡 Hint

Consider how to maintain availability when Spot Instances are interrupted.

Mixing Spot Instances with On-Demand Instances in an Auto Scaling group provides cost savings while maintaining availability. On-Demand Instances serve as fallback when Spot Instances are interrupted.

❓ Configuration

advanced

Spot Instance interruption handling configuration

Which AWS service or feature allows you to automatically handle Spot Instance interruptions by launching replacement instances?

A AWS Lambda with CloudWatch Events monitoring Spot interruptions.

B AWS Elastic Beanstalk configured with Spot Instances only.

C EC2 Auto Scaling group with mixed instances policy including Spot Instances.

D AWS Systems Manager Automation documents for manual instance replacement.

💡 Hint

Think about automated scaling and instance replacement features.

EC2 Auto Scaling groups with mixed instances policies can automatically replace interrupted Spot Instances by launching new ones, maintaining desired capacity.

❓ security

advanced

Security considerations for Spot Instances

What is a key security best practice when using Spot Instances in your AWS environment?

A Assign broad IAM roles to Spot Instances to simplify access management.

B Use dedicated security groups and restrict network access to Spot Instances.

C Disable encryption on Spot Instances to improve performance.

D Store sensitive data only on Spot Instance local storage for faster access.

💡 Hint

Consider how to protect instances that may be interrupted or replaced frequently.

Using dedicated security groups with restricted network access limits exposure and protects Spot Instances, which can be interrupted and replaced frequently.

❓ service_behavior

expert

Spot Instance interruption notice timing

How long before AWS terminates a Spot Instance does it provide an interruption notice, and how can you detect it programmatically?

A Two minutes; by querying the instance metadata service for the interruption notice URL.

B Ten minutes; by subscribing to SNS notifications configured on the instance.

C Instant termination; no programmatic detection is possible.

D Five minutes; by polling the EC2 metadata endpoint for interruption time.

💡 Hint

Recall the exact timing and how AWS exposes interruption notices to instances.

AWS provides a two-minute interruption notice accessible via the instance metadata service at a specific URL. Applications can poll this URL to detect imminent termination.