Why is Loadster saying the cloud capacity has been exceeded?

Loadster relies on public cloud providers (Amazon Web Services and Google Cloud Platform) to run the on-demand instances required for your load test. A big load test can require thousands of cloud instances!

The cloud requirements are especially heavy if you’re running Browser Bots with their resource-intensive headless Chrome browsers.

Of course, these public cloud providers also run infrastructure for thousands of other individuals, businesses, and governments around the world. Most of the time they are able to ensure capacity, but we’ve seen occasions when they lack capacity in one or more regions.

In most cases, this isn’t anything specific to Loadster or even a quota-related issue… it’s a simple case of the provider not enough hardware running at that cloud region at the moment you want to run your load test.

Predicting Cloud Capacity is Hard

To further complicate matters, they don’t tell us if they lack capacity ahead of time. You may occasionally launch a load test and wait around for a few minutes, only to find out that the test failed to start due to a shortage with the cloud provider.

Loadster takes steps to track the historical launch success rate in each region, and uses certain heuristics to estimate how much capacity can usually be expected to be available in each region.

Avoiding Test Launch Failures

When you’re designing your load test scenario, Loadster will tell you if we think you’ve allocated too many Browser Bots and/or Protocol Bots to one region or another. If you see that the bots you’ve assigned to a region exceed its estimated capacity, we recommend moving some of those bots to a different region.

We’ve found that the bigger AWS-powered regions tend to be the most reliable and have the most warm metal at any given time. Also, the AWS API informs us quickly at launch time whether they have capacity, so you aren’t stuck waiting around if you select an AWS region. Unfortunately, the GCP API doesn’t provide this at the time of writing, so all we can do is ask for the instances and then wait around to see if they start.

You can review our list of Loadster Cloud Regions to see which provider hosts each region.