Sometimes a particular resource_class type may be temporarily unavailable for various reasons. In such cases, it would be useful if customers could specify a prioritized list of preferred resource classes or tags. CircleCI could then automatically select the first available option from that list to run the job.

This provides flexibility across a variety of scenarios and helps customers plan for outages or capacity shortages without building complex fallback logic or maintaining multiple backup workflows.

Example:

resource_class: xxx

resource_tags: [linux, my-own-runner-x86, macos]

In this example, if both linux and my-own-runner-x86 are unavailable, CircleCI could fall back to macos to ensure the job still runs without timing out or failing.