Acorn was an application packaging and deployment framework for Kubernetes that let developers define an entire app — containers, volumes, secrets, and ingress — in a single file written in Acornfile, a CUE-derived configuration language. acorn run would then push that bundle to a cluster as an OCI image and reconcile it into the underlying Kubernetes primitives.
The project was built by the team behind Rancher and k3s (Darren Shepherd, Ibrahim Jarif, and others at Acorn Labs) as an attempt to hide Helm charts and raw YAML behind a simpler developer-facing abstraction. It shipped a CLI, a per-cluster controller, and a managed SaaS (Acorn Cloud) for sharing apps across clusters.
Acorn Labs pivoted away from the runtime in 2024 to focus on GPTScript and AI tooling, and the repository is no longer maintained. If you need the same shape of abstraction today, look at Score, KubeVela, Radius, or just Helm with a thin wrapper — all of which are actively developed. With the repository archived and no security updates planned, migration is the sensible path.