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GCP releases Spot VMs, the next generation of Pre-emptible VMs

cloud.google.com

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Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#61

Post by cherioo »

Sanguinaire wrote: post #47

It's weird how the 3 major clouds have taken different paths to what must be an almost identical resource allocation problem. AWS has had this kind of spot instance for years, but with a 2 minute grace period rather than the 30 seconds GCP is offering. Azure and GCP both originally went with the 24-hour cutoff (which can easily be replicated on a regular spot instance if needed), but now GCP are backing off on that r…

They probably thought 24 hours limitation can store some design wins; their customers may have proved them wrong.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#62

Post by pm90 »

titzer wrote: post #16
wmf wrote: post #10

Earlier quoted context omitted.

You might be misunderstanding how spot works. The VM either runs at full speed or not at all so you know what you're getting.

Nevertheless, doesn't that force you to divide your work up into units somehow and manage external storage to track what/how much is done?

There are tools that enable this (e.g. look at temporal.io).

As for external storage: yes, you do generate more metadata, but that's often a tiny fraction of the cost saved by moving to spot machines.

In general, these tools are adopted more for increasing reliability of existing systems, but I predict they would be a neat fit to run them on spot machines.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#63

Post by bb101 »

From https://cloud.google.com/compute/docs/instances/preemptible: "Spot VMs (Preview) are the latest version of preemptible VM instances. Preemptible VMs continue to be supported for new and existing VMs, and preemptible VMs now use the same pricing model as Spot VMs. However, Spot VMs provide new features that are not supported for preemptible VMs. For example, preemptible VMs can only run for up to 24 hours at a time, but Spot VMs do not have a maximum runtime."

So preëmptible VMs are still supported but may now cost as much as 40% of non-preëmptible VMs, "to reflect the supply-demand dynamics of Compute Engine’s excess capacity." That's quite a big change from the current pricing structure.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#65

Post by junon »

pushrax wrote: post #42
titzer wrote: post #16

Earlier quoted context omitted.

Nevertheless, doesn't that force you to divide your work up into units somehow and manage external storage to track what/how much is done?

The reality at scale is that all cloud VMs are preemptible and unreliable. You can pay more to increase the probability of uptime but inevitably have to recover from failure sometimes.

This is absolutely the correct way of thinking about this problem, and exactly how most people I've seen successfully use pre-empt instances treat them as well.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#66

Post by ggm »

sudhirj wrote: post #60
ggm wrote: post #50

Is this a sign they have surplus pre-emptible capacity on their architecture for non-premptible VMs, and so worrying, if you think they have enough customers to sustain the model? (google could run negative forever: the point is, some VP won't want to, and the KPI will morph to "kill it")

No, all clouds must overprovision their datacenters to handle sudden peak demand. Everybody doubles or tripes their clusters around the holiday season or shopping festivals, for example. For the other 350 days of the year, this capacity often lies unused - so they're auctioned off to the highest bidder (but usually at spot rates much less than the full rent). They're pre-emptible because if you need the servers for s…

The overprovisioning makes this kind of product attractive. A small downside is a surge in complaints from customers who experience virtually no pre-empt, and then build a belief it's engines for cheap.. until the machine stops.

Somebody once told me a policy of random offswitch helps

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#67

Post by sudhirj »

ggm wrote: post #66
sudhirj wrote: post #60

Earlier quoted context omitted.

No, all clouds must overprovision their datacenters to handle sudden peak demand. Everybody doubles or tripes their clusters around the holiday season or shopping festivals, for example. For the other 350 days of the year, this capacity often lies unused - so they're auctioned off to the highest bidder (but usually at spot rates much less than the full rent). They're pre-emptible because if you need the servers for s…

The overprovisioning makes this kind of product attractive. A small downside is a surge in complaints from customers who experience virtually no pre-empt, and then build a belief it's engines for cheap.. until the machine stops. Somebody once told me a policy of random offswitch helps

That’s probably why Google added the 24h cap, so you don’t get used to the machines being around all the time. Bit like a forced chaos monkey.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#68

Post by bb101 »

bb101 wrote: post #63

From https://cloud.google.com/compute/docs/instances/preemptible : "Spot VMs (Preview) are the latest version of preemptible VM instances. Preemptible VMs continue to be supported for new and existing VMs, and preemptible VMs now use the same pricing model as Spot VMs . However, Spot VMs provide new features that are not supported for preemptible VMs. For example, preemptible VMs can only run for up to 24 hours at a…

Looking through our history, it looks like us-east-1 preëmptible VMs were a flat 30% the cost of non-preëmptible VMs. So in the worst-case scenario, we'll be paying 10% more for the same product, but also potentially saving up to 19% in periods where GCP has excess capacity.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#69

Post by secondcoming »

bb101 wrote: post #64
secondcoming wrote: post #53

Great, now fix your terrible UI.

I find GCP's UI easier to use than AWS' by orders of magnitude.

I've found GCP's UI to be a racy mess. If you ask it to do something trivial like removing an instance from an Instance Group, it can show that it has done it when, in fact, it hasn't. Want to switch projects? Better remember to hit F5.

Re: GCP releases Spot VMs, the next generation of Pre-emptible VMs

#70

Post by dagw »

titzer wrote: post #16
wmf wrote: post #10

Earlier quoted context omitted.

You might be misunderstanding how spot works. The VM either runs at full speed or not at all so you know what you're getting.

Nevertheless, doesn't that force you to divide your work up into units somehow and manage external storage to track what/how much is done?

That is probably the primary use case for spot instances and certainly how I tend to used them. I have a few thousand files that need processing and each files takes 30 minutes. So I spin up 100 spot instances and use a small script to copy the file from a control machine to the next available remote machine, start the processing script, and then copy the result back when done.

I've also got another script that keeps track of how many spot instances are currently running and spins up some new ones (possibly in a different region) if they fall below a certain level.

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