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Comment by user5994461 | Hacker News Reader

AWS Spot Instances are under bid. The highest bidder takes the instances, the price changes all the time.

Google Spot Instances (preemptibles) are 80% off and that's it. It's simple.

Can't you just bid for 20% of the original price and get the same behavior?

In AWS you simply tell how much you're willing to pay to keep the instance uninterrupted. If there's someone who is willing to pay more, they will get the instance from you and yours will be shut down.

The main factor is the market for this unused CPU time, a bid of 20% could be vastly different on each service. The GCE pricing model in a way has a sort of step function applied to the pricing, whereas AWS you can bid however you like, how this effects consumer usage I would guess is higher cost on AWS due to perceived competition. This is all assuming the CPU time on machines is constant.

AWS also tends to have different prices in different regions and for different sized machines, so there's more work involved in making your 20% work.

With Spot, if the market price goes above .2x retail, and your job runs long enough then you never succeed with Spot.

By comparison, if you are able to create a preemptible VM you are guaranteed to pay .2x retail and then likely (but not guaranteed) to have 24h to do your work.

tl;dr: A maximum bid of .2x retail isn't equivalent to preemptible. There's almost certainly a bid for a given instance for a given runtime that would result in the same price, but it varies over time, space, runtime and instances shape.

Disclosure: I work on Google Cloud (and launched preemptible VMs)

> likely (but not guaranteed)

In my several years experience using GCE it is indeed extremely likely. Two years ago it wasn't very likely, but it became very likely about a year ago. Incidentally, I'm the guy that convinced Drew Sutherland of this article to use GCE in the first place :-).

That does sound pretty nice.

We run specific components of our application in spot instances across different regions and from what I have seen in the last 3 months is that the price is generally much less than 80%. I'd say is less than 20% most of the time, but some times there is a peak and it goes beyond 150% for 1 to 3 hours, the frequency of these events may vary but I'd say once a week.

I think AWS might be cheaper in this regard but less predictable, so it is a tradeoff.

Edit: I haven't looked yet into "Spot Fleets".

Not 80%, 80% off.

Wops, sorry for my confusion!

Then it is definitely interesting :)

Looking at the spot prices on our AWS account (us-east-1), most of the time you're looking at around 25% full price. Some instance types seem to go lower than this (r4 is about 12%) but it looks like the 'resting point' is around 25% for the ones I skimmed.

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