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The fundamental difference seems to be that Google's prices are fixed, whereas AWS uses a "market" model, which frequently sees crazy prices (well over the on-d

by vosper 11y ago

The fundamental difference seems to be that Google's prices are fixed, whereas AWS uses a "market" model, which frequently sees crazy prices (well over the on-demand price) especially in us-east-1. I say "market" because no-one really knows how the spot market place actually works. We've had machines run for weeks, and other times the prices fluctuate in bizarre ways and we can't get out preferred instance types for hours or (in the worst case) days. There's an interesting analysis here: http://santtu.iki.fi/2014/03/20/ec2-spot-market/ http://santtu.iki.fi/2014/03/20/ec2-spot-market/

CoolGuySteve 11y ago
We had the same problem with getting priced out of c3.8xlarge in Virginia. We fixed it by changing our allocation algorithm to find alternate instance types and zones. For example, instead of 1 c3.8xlarge, it might pick 2 c3.4xlarge instances or a cc2.8xlarge. Seems to work so far. I looked through the pricing table and played with the calculator, it seems something equivalent to our needs would cost around a third more on google but each cpu would have twice as much ram. Not worth it for us.
- boulos 11y ago
  For people coming from AWS, we currently don't have an instance shape that lines up with the c3/c4 ratio (pushing you either to our n1-standards or n1-highcpu-. Can you get by with less memory? Note: we're very aware of this pain point, and maybe you'll see something soon ;).
  - CoolGuySteve 11y ago
    We need maybe 1GB for each job, but we need some leeway to avoid the OOM killer when a group of work units is larger. Swapping takes so long that it's not cost effective. But to be honest about the situation, the cost would have to be much lower to make it worthwhile for me to rewrite our scheduler on Google's API.
teraflop 11y ago
I don't really see a fundamental difference except that Google's offering is more opaque and less flexible. Instead of "your instance got killed, but you can restart it if you're willing to pay $x/hour", you get "your instance got killed, tough luck." EC2's spot market fluctuates based on supply and demand, and there's no reason to think the same forces won't apply to GCE.
- jpatokal 11y ago
  It's not really that different: If your preemptible GCE instance gets killed, you can try restarting it as a 'normal' (non-preemptible) instance. But in Google's case, both prices will be predictable.

by vosper 11y ago

CoolGuySteve 11y ago

We had the same problem with getting priced out of c3.8xlarge in Virginia. We fixed it by changing our allocation algorithm to find alternate instance types and zones. For example, instead of 1 c3.8xlarge, it might pick 2 c3.4xlarge instances or a cc2.8xlarge. Seems to work so far. I looked through the pricing table and played with the calculator, it seems something equivalent to our needs would cost around a third more on google but each cpu would have twice as much ram. Not worth it for us.

boulos 11y ago
For people coming from AWS, we currently don't have an instance shape that lines up with the c3/c4 ratio (pushing you either to our n1-standards or n1-highcpu-. Can you get by with less memory? Note: we're very aware of this pain point, and maybe you'll see something soon ;).
- CoolGuySteve 11y ago
  We need maybe 1GB for each job, but we need some leeway to avoid the OOM killer when a group of work units is larger. Swapping takes so long that it's not cost effective. But to be honest about the situation, the cost would have to be much lower to make it worthwhile for me to rewrite our scheduler on Google's API.

teraflop 11y ago

I don't really see a fundamental difference except that Google's offering is more opaque and less flexible. Instead of "your instance got killed, but you can restart it if you're willing to pay $x/hour", you get "your instance got killed, tough luck." EC2's spot market fluctuates based on supply and demand, and there's no reason to think the same forces won't apply to GCE.

jpatokal 11y ago
It's not really that different: If your preemptible GCE instance gets killed, you can try restarting it as a 'normal' (non-preemptible) instance. But in Google's case, both prices will be predictable.