Speeding up Terraform caching with OverlayFS

The Terraform plugin cache, unfortunately, does not support concurrent Terraform inits. This leaves us no other choices than disabling caching or serializing our inits, both of which would significantly slow down our Terraform pipelines, which are expected to make hundreds of plans in single-digit minutes.

In this talk we go over how we solved that with OverlayFS, a tool we rarely see outside of its niche, but so powerful that it helped us cut our plan times by 90%!