AWS re:Post
repost.aws › questions › QUezAlgpQFSNuDMPycP7a9rQ › spot-fleet-for-on-demand-instance
spot fleet for on demand instance | AWS re:Post
June 14, 2025 - If you still prefer the Fleet approach, ... RunInstances API. Remember that the main benefit of Spot Fleet is the ability to combine On-Demand and Spot Instances to optimize for cost and availability....
Amazon Web Services
docs.aws.amazon.com › amazon ec2 › user guide › ec2 fleet and spot fleet › work with spot fleet
Work with Spot Fleet - Amazon Elastic Compute Cloud
The fleet launches On-Demand Instances when there is available capacity, and launches Spot Instances when your maximum price exceeds the Spot price and capacity is available.
Videos
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Did You Know That Amazon EC2 Spot Fleet Supports Automatic Scaling?
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AWS - EC2 Fleet | New feature | Combine Spot & On-demand EC2 ...
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Leveraging Amazon EC2 Spot Best Practices Using the New Capacity ...
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Did You Know That You Can Mix and Match Amazon EC2 Spot Instances ...
Boltops
blog.boltops.com › 2018 › 07 › 15 › what-is-the-difference-between-spot-fleet-vs-spot-instances
What is the Difference Between Spot Fleet vs Spot Instances - BoltOps Blog
Spot Fleets make it much easier to design a Highly Available fault-tolerant architecture with spot instances. With spot fleets, you can request a variety of servers for the spot fleet request.
Amazon Web Services
docs.aws.amazon.com › amazon ec2 › user guide › ec2 fleet and spot fleet › configuration options for your ec2 fleet or spot fleet › use allocation strategies to determine how ec2 fleet or spot fleet fulfills spot and on-demand capacity
Use allocation strategies to determine how EC2 Fleet or Spot Fleet fulfills Spot and On-Demand capacity - Amazon Elastic Compute Cloud
However, when launching instances, the fleet uses the allocation strategy that you specify to pick the specific pools from all your possible pools. (Linux instances only) If you configure your Spot Instance to launch with AMD SEV-SNP turned on, you are charged an additional hourly usage fee that is equivalent to 10% of the On-Demand hourly rate
Amazon Web Services
amazonaws.cn › products › amazon ec2 › amazon ec2 spot
Amazon EC2 Spot Instances FAQs
1 week ago - The main differences are that Spot instances typically offer a significant discount off the On-Demand prices, your instances can be interrupted by Amazon EC2 for capacity requirements with a 2-minute notification, and Spot prices adjust gradually based on long term supply and demand for spare ...
Reddit
reddit.com › r/aws › ec2 on-demand pricing via spot requests (fleet)
r/aws on Reddit: EC2 on-demand pricing via Spot Requests (fleet)
November 29, 2022 -
I'm having a hard time understanding the pricing for EC2 on-demand instances when launched via "spot requests" and would be grateful if someone with more AWS experience can clue me in :)
So EC2 on-demand pricing is relatively straight forwarded when launching on-demand instances in a standard way (Console -> EC2 -> Instances -> Launch instance -> Select Instance type)
E.g. for t2.micro the price is 0,018 USD
However, when the same instance is launched via "spot requests" (Console -> EC2 -> Spot request -> Request spot instances) it is much cheaper. I understand what spot instances are (they can be reclaimed by the AWS with short notice), but with spot requests, it is possible to request on-demand capacity along with spot capacity... It is possible to request only on-demand capacity and get on-demand instances much cheaper.
E.g. "spot request" config for a single on-demand instance
Spot request capacity definition defining a single on-demand instanceGiven that instance is provisioned this way it is significantly cheaper than instances of the same type started via standard "Instance launch" flow. See the savings section for t2.micro on-demand instances started via "spot request" on the following image:
So for the t2.micro instance:
Standard launch => 0,018USD per hour
Spot request launch => 0,004USD per hour
So the question is what is the catch with on-demand instances started via "spot requests"? Can they also be reclaimed at short notice (I didn't find any docs stating so...)? Is there something else that I'm missing here?
Top answer 1 of 2
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Either it’s a bug in the savings screen you have screenshotted, you are misunderstanding what that view shows or you’ve found a major bug with EC2 pricing that nobody else has. My guess is it’s one of the first two. On demand is on demand no matter where you spin it up from. If you exclusively run this instance for an entire day and go back and look at cost explorer/CUR you can see what you were actually billed for it.
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Spot pricing is dynamic. standard is a fixed price. look again in an hour and the price of spot instances will have moved. In general they are cheaper. On the big established aws regions the prices have pretty predictable patterns. But other times it can be unavailable or overpriced. Making it a good way to run casual "I don't care when this gets done" stuff, but not for 100% uptime launch now stuff.
AWS
learnaws.org › 2020 › 01 › 01 › aws-spot-fleet-reduce-cost-improve-reliability
How to use AWS Spot Fleet to lower costs and improve reliability
Before we go deeper into Spot Fleet, it is useful to understand how Spot instances work. AWS has three tiers of EC2 instances. They are: On-Demand Instances: This is generally the default option when you create an EC2 instance. Most of the time, when you see any EC2 pricing online, it refers to the On-Demand pricing.
Amazon Web Services
docs.aws.amazon.com › amazon ec2 › user guide › ec2 fleet and spot fleet
EC2 Fleet and Spot Fleet - Amazon Elastic Compute Cloud
Through Capacity Rebalancing, a fleet can also monitor and proactively replace your Spot Instances that are at an elevated risk of interruption. ... A fleet can use an On-Demand Capacity Reservation to reserve On-Demand capacity.
Amazon Web Services
docs.aws.amazon.com › amazon ec2 › user guide › ec2 fleet and spot fleet
On-Demand in Spot Fleet
A fleet can launch multiple purchase options (Spot and On-Demand Instances), allowing you to optimize costs through Spot Instance usage.
Ec2spotworkshops
ec2spotworkshops.com › launching_ec2_spot_instances › ec2_fleet.html
Launching EC2 Spot Instances via EC2 Fleet :: EC2 Spot Workshops
The EC2 Fleet request specifies separately the target capacity for Spot and On-Demand Instances using the OnDemandTargetCapacity and SpotTargetCapacity fields inside the TargetCapacitySpecification structure.
Spot.io
spot.io › home › aws auto scaling › aws spot fleet: the first step to saving with spot instances
AWS Spot Fleet: The first step to saving with Spot Instances
October 12, 2025 - This depends on availability of ... automatically fallback to on-demand—Spot Fleet does not let you automatically failover to an on-demand instance when a spot instance fails....
Ec2spotworkshops
ec2spotworkshops.com › launching_ec2_spot_instances › spot_fleet.html
(Optional) - Launching an EC2 Spot Instance via Spot Fleet request :: EC2 Spot Workshops
This Spot Fleet will maintain a weighted target capacity of 12, as specified in the value for TargetCapacity. Additionally, you are specifying an On-Demand target capacity of 4. Remember that Amazon EC2 calculates the difference between the total capacity and On-Demand capacity in order to launch Spot Instances.
Medium
alicethearchitect.medium.com › a-comprehensive-guide-to-ec2-spot-instances-and-spot-fleets-maximizing-cloud-cost-savings-6abfbdd3b4de
A Comprehensive Guide to EC2 Spot Instances and Spot Fleets: Maximizing Cloud Cost Savings | by Alice the Architect | Medium
October 4, 2024 - In this article, we’ll dive into ... use unused Amazon EC2 capacity at a significantly reduced cost — up to 90% cheaper compared to On-Demand Instances....
Sumo Logic
sumologic.com › app catalog › amazon and aws › amazon ec2 spot fleet
Amazon EC2 Spot Fleet | Sumo Logic Docs
A Spot Fleet is a set of Spot Instances and optionally On-Demand Instances that is launched based on criteria that you specify. The Spot Fleet selects the Spot capacity pools that meet your needs and launches Spot Instances to meet the target ...
Spot.io
spot.io › home › aws ec2 pricing › what are aws spot instances?
What are AWS spot instances?
December 13, 2022 - The longer the defined duration, the lower the discount provided for the spot instance. Defined duration instances grant discounts of 30-50% vs. On-Demand pricing. Spot Fleet is a collection of spot instances.
Top answer 1 of 2
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Your observation about Spot instances not honoring latency values provided to `StartMatchmaking `is correct. The `FlexMatch `matchmaking service will try to optimize placement for On-Demand game sessions based on latency, but it does not have the same level of control over Spot instance placement.
When using Spot instances, the overall placement is determined by the queue configuration and available Spot capacity. Some key points:
Spot instances may be terminated at any time if capacity is needed, so `FlexMatch `cannot guarantee placing matches in a specific region even if latency is better elsewhere.
You can try listing the region with your fleet as the first destination in the queue to increase chances of matches being placed there. But FlexMatch has less control over Spot placements than On-Demand.
https://docs.aws.amazon.com/gamelift/latest/developerguide/tutorial-queues-spot.html
2 of 2
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Hey OptimalGamer,
As Giovanni pointed out, FlexMatch doesn't distinguish between SPOT and ON_DEMAND; however, there are recommended best practices you can follow to balance costs while maintaining reliability without "forcing". I recommend reading through the whole article on setting up queues in GameLift's documentation (ending with the tutorial Giovanni linked), but some highlights are:
* Queues provide customization for prioritizing Cost vs Latency vs hard-coded order etc: https://docs.aws.amazon.com/gamelift/latest/developerguide/queues-design.html#queues-design-priority
* GameLift provides various best practices including recommending a backup ON_DEMAND fleet available for each location you want SPOT: https://docs.aws.amazon.com/gamelift/latest/developerguide/queues-best-practices.html
A common-place strategy is to prioritize Latency first then Cost second while having ON_DEMAND fleets to backup your SPOT fleets. This means that your players will place first in locations they have the best latency, and your SPOT fleets will be prioritized over ON_DEMAND to reduce costs as your SPOT fleet scales up to meet the demand.
It's worth noting that GameLift queues can only place into fleets that have space available, so you should look into scaling policies for your fleets to make sure you can handle increases and drops in player traffic: https://docs.aws.amazon.com/gamelift/latest/developerguide/fleets-autoscaling.html
Regards,
Top answer 1 of 2
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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.
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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.
Finout
finout.io › blog › aws-spot-instances
What Are AWS Spot Instances, Pros/Cons, and 6 Ways to Save Even More
May 22, 2025 - AWS spot instances offer several advantages that make them an attractive option for certain types of workloads. Here are the key benefits: Cost savings: Spot instances can be up to 90% cheaper than on-demand instances, making them an excellent ...
Nordcloud
nordcloud.com › home › content hub › everything you needed to know about spot instances
Everything you needed to know about spot instances
December 15, 2022 - You can then set up your bid price globally for around the same price as the m4.large On-demand price. Spot fleet then attempts to launch the specified instances that will result in the lowest cost.
Spot
spot.io › home › aws spot instances and diy
AWS Spot Instances and DIY | Spot.io
September 26, 2024 - When using Spot Fleet, there will be no prioritized placement of workloads onto unused Reserved Instances. You will only be able to leverage the cost-savings of Reserved Instances in the event that you have a blended cluster of On-Demand and ...