Run runner VMs on spot nodes to cut compute costs, without failing jobs when a node is reclaimed. Set runner.enableUnsafeRetries on a resource class, and a job that is still running when its VM shuts down is retried on another VM instead of failing. The job restarts from the beginning, so only enable it for jobs that are safe to run more than once. Off by default. Requires machine runner 3.1.13 or later.
Fixes
A resource class can now override resourceClassDefaults with false, zero or empty values. Previously these were ignored and the class got the default instead. For example, a class can now set grantSudo: false or headroom: 0, or set a list to empty to clear a default. A class that leaves out scaleDownDelay also no longer has it forced to 0s.