Amazon EC2 Spot Pricing – Why bother with regular EC2 instances?
Amazon announced today Spot prices for EC2 instances - market-driven pricing for unused Amazon EC2 capacity.
You bid an amount per hour of usage, and if the spot price is equal to or lower than the amount, you then get the instance for that hour. This would be a great way to do things such as process time-insensitive data (maybe log files, updates of denormalized data, etc.)
A quick look at the historic graph, shows spot pricing for a Linux m1.small running between $0.025 and $0.35 per hour, averaging $0.030 per hour. Normal instances cost $0.085 per hour. Reserved instances cost $0.030 per hour.
The question that I’m most intrigued with currently is whether we should just move all of our normal instances to Spot instances. We would then set bids equal to the regular pricing. In theory, our pricing should never be worse than what we pay currently and would most likely be much better.
The long-term outcome is likely to be that all of EC2 pricing (except for the Reserved instances) moves to Spot Pricing.
The only risk I can think of is other companies doing the same thing but bidding more than the regular instance price. Then we’d get screwed as all of our instances are turned off. But of course, any company that switches from a regular instance to Spot instances, should free up an equal amount of capacity as they are currently using.
What am I missing? Are there other risks to this strategy?
