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Ask HN: Is there an EC2 Spot Instance shortage?

13 points by mattlong ↗ HN
I'm new to dealing with spot instances, so maybe i'm just missing something, but why am I unable to get a single c1.xlarge spot instance in us-east-1b activated? I put in an absurdly high max price or $10/hr yesterday for 1 instance and it has still not been started.

How can the going rate be $0.23/hr and my $10 bid not get honored? Isn't the idea that if there's an extra capacity of X machines, it goes to the X highest bids? Shouldn't the rate be much higher than $0.23/hr if there are very few spot instances available?

6 comments

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inaka
maybe $10 is so high they rejected it? similar to adding a zero on a stock purchase at etrade - they'll call you and tell you you overbid...
mattlong
interesting indeed. I hadn't considered this. If this is the case, it's unfortunate they don't reject bids saying they're too high.

I just submitted several more otherwise identical bids at different prices to see what happens...

mattlong
FYI, the price doesn't seem to matter. A bid for $.50 isn't being fulfilled either. I still don't understand why a bid higher than the going rate isn't being fulfilled. :-/
nissimk
3 words: christmas shopping season
newobj
Speaking only as an EC2 user, I have not seen any evidence that there's any kind of "king of the hill" bidding going on w/ spot instances. You get machines if your "bid" exceeds the current spot price AND there is available capacity. What controls the current spot price? I don't know.

I get the feeling that Amazon is experimenting with really trying to create a market here, but that there are still some very strong controls and limits with respect to how the pricing is computed. For example, most spot prices tend to max out at the reserved instance rate. I highly doubt that's a market effect. It's certainly worth bidding over the reserved, but under the normal, instance rate. I'm guessing that it's going to be difficult to create a market that is unrestricted but still preserves the quality of the user experience, in terms of rapid oscillations around different support points of bid prices, preventing anyone from keeping a server up for a coherent amount of time. You could bid-bomb DOS the market too, for example, if you were willing to spend a little money. You only need to hold the machines for an hour...