What is an AWS Spot Instance?
An AWS Spot Instance is a type of Amazon EC2 (Elastic Compute Cloud) instance that allows users to bid on spare Amazon EC2 computing capacity at discounted rates compared to On-Demand instances. Spot Instances can offer significant cost savings but come with the caveat that they can be terminated by AWS with little notice if the capacity is needed for On-Demand instances.
AWS Spot Instances – Key Features
Use of Spare Capacity
Spot Instances are launched on spare capacity that is available when the demand for On-Demand and Reserved Instances is met. When the demand for these other instance types increases, Spot Instances may be reclaimed with a two-minute termination notice.
Instance Types and Availability Zones
Spot Instances support a wide range of instance types and are available in multiple Availability Zones within an AWS region.
Interruptible Instances
Amazon EC2 Spot Instances can be terminated by AWS with a two-minute notification if the capacity needs to be reclaimed. Users must design their applications to handle interruptions gracefully.
Cost Savings
Spot Instances often provide substantial cost savings compared to On-Demand Instances, making them suitable for fault-tolerant and flexible workloads.
Spot Fleets
Users can create Spot Fleets, which are collections of Spot Instances, On-Demand Instances, and optionally Reserved Instances or a combination of these. Spot Fleets provide flexibility in managing capacity across different instance types and across Availability Zones.
Integration with Auto Scaling Groups
AWS EC2 Spot Instances can be integrated with Auto Scaling Groups, allowing users to automatically scale the number of instances based on demand. Auto Scaling Groups can combine On-Demand and Spot Instances for optimal cost efficiency.
Instance Pools
Spot Instances can be launched from instance pools, which are groups of instances that are similar in size and configuration. Pools help improve capacity and fulfilment rates.
Spot Block Duration
Users can request Spot Instances with a specified duration (1 to 6 hours), known as Spot Block instances. Spot Block instances provide a more predictable pricing model for workloads with defined start and end times.
Usage Scenarios
AWS EC2 Spot Instances are suitable for fault-tolerant applications, batch processing, data analysis, scientific simulations, and other workloads that can tolerate interruptions and are cost-sensitive.
Spot Market Pricing History
Users can view the Spot Instance pricing history to understand trends and make informed bidding decisions.
Spot Instance Advisor
The Spot Instance Advisor guides on choosing instance types, Availability Zones, and bidding strategies based on historical Spot pricing data.
How AWS Spot Instances Work
AWS Spot Instances allow users to bid on unused EC2 capacity at potentially lower costs. Users specify a maximum bid price, and instances are launched if the current Spot price is below this bid. Spot prices fluctuate based on supply and demand. If the Spot price exceeds the bid, AWS can terminate the instance with a two-minute warning. Spot Instances are ideal for workloads that can handle interruptions, such as batch processing, data analysis, and CI/CD pipelines. They can be managed using Spot Fleets or integrated into Auto Scaling groups for flexibility and efficiency.
How Spot Instances Lower Costs
Spot Instances offer significant cost savings by utilizing AWS’s spare EC2 capacity. These instances can be up to 90% cheaper than On-Demand instances due to their dynamic pricing model, which adjusts based on real-time supply and demand. This makes them suitable for non-critical, fault-tolerant workloads that can be paused and resumed. By bidding for lower prices and leveraging periods of excess capacity, users can drastically reduce their cloud computing expenses while maintaining operational efficiency.
What is AWS Spot Instance Pricing?
EC2 Spot Instances are priced based on supply and demand. Users bid for the unused capacity, and the price is determined by the market conditions. When the Spot price is below the user’s bid price, the instance runs.
How to Create Spot Instances in AWS
You can launch an AWS EC2 Spot Instance by creating a Spot Instance request.
1. Login to the AWS console and navigate to the EC2 console.
2. Select the AMI to launch the spot instance. In most cases, customers will be using the launch templates.
3. Select the role to use.
4. Configure the target capacity. You can choose the interruption behaviour based on your requirement. You will also have an option to set the price for the instance.
5. Select the VPC and desired subnet to launch the instance
6. Select the instance type.
7. You can see the fleet strength and estimated hourly price.
8. Once the request is fulfilled, you can see that the fleet created the new instance. Similar to the EC2 instance, you can access it and the instance will be visible on the EC2 instance page as well.
Conclusion
Amazon EC2 Spot Instances are a cost-effective way to use spare Amazon Elastic Compute Cloud (EC2) capacity. Unlike On-Demand Instances or Reserved Instances, which have fixed pricing, Spot Instances allow you to bid for unused EC2 capacity, potentially providing significant cost savings. It’s important to note that while Spot Instances offer cost savings, they are not suitable for all types of workloads, especially those that require high availability and cannot tolerate interruptions. Users should design their applications with fault tolerance in mind and have mechanisms to handle Spot Instance interruptions gracefully.
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