Q45

Question 45. What Is The Difference Between A Spot Instance And A Demand Instance On Ec2 ?

Answer :

“On-Demand” instances allow the user to use the compute by hour without requiring long term commitment. There are no guarantees that the user will always be able to launch specific instance types in an availability zone, though AWS tries it’s best to meet the needs. This service is preferable for POCs and they do not suffer an interruption of the service(by AWS) like Spot instances.

“Spot” instances are a bid_for_low_price version of On-Demand instances, but could be shut down by AWS anytime the Spot instance price goes higher than bid price. Spot price fluctuates based on the supply and demand of the capacity. It’s essentially the leftover capacity of AWS to be used. There is no difference in the performance compared to On-Demand instances and is usually cheaper than On-demand instances as there is no guarantee provided over the availability. The user can choose a start time and end time for the instances or can make a persistent request(no end time specified) for this service. This service is preferable for computing needs which are not tied to any deadlines, computing needs are large and the interruption of service is acceptable.

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