How often does Google Cloud Preemptible instances preempt (roughly)?

Question

I see that Google Cloud may terminate preemptible instances at any time, but have any unofficial, independent studies been reported, showing "preempt rates" (number of VMs preempted per hour), perhaps sampled in several different regions?

Given how little information I'm finding (as with similar questions), even anecdotes such as: "Looking back the past 6 months, I generally see 3% - 5% instances preempt per hour in uswest1" would be useful (I presume this can be monitored similarly to instance count metrics in AWS).

Clients occasionally want to shove their existing, non-fault-tolerant code in the cloud for "cheap" (despite best practices), and without having an expected rate of failure, they're often blind-sighted by the cheapness of preemptible, so I'd like to share some typical experiences of the GCP community, even if people's experiences may vary, to help convey safe expectations.

Answer 1

Thinking about “unofficial, independent studies” and “even anecdotes such as:” “Clients occasionally want to shove their existing, non-fault-tolerant code in the cloud for "cheap"” it ought to be said that no one architect or sysadmin in right mind would place production workloads with defined SLA into an execution environment without SLA. Hence the topic is rather speculative.

For those who is keen, Google provides preemption rate expectation:

For reference, we've observed from historical data that the average preemption rate varies between 5% and 15% per day per project, on a seven-day average, occasionally spiking higher depending on time and zone. Keep in mind that this is an observation only: Preemptible instances have no guarantees or SLAs for preemption rates or preemption distributions.

Besides that there is an interesting edutainment approach to the task of "how to make inapplicable applicable".