K3s

K3s runs production Kubernetes in 100MB of RAM, packaged as a single binary under 70MB. Same Kubernetes API, same kubectl commands, same ecosystem, just without the components most people never touch. It runs on everything from a Raspberry Pi to production cloud servers. Fully free under Apache 2.0. No paid tier, no enterprise version, no feature gating. SUSE/Rancher maintains it, and they make money on Rancher (the multi-cluster management layer), not K3s itself.

Installation is a one-liner: `curl -sfL https://get.k3s.io | sh -`. You have a running Kubernetes cluster in under 60 seconds. Adding worker nodes is equally simple. It bundles containerd, Flannel (networking), CoreDNS, and Traefik (ingress) so you don't have to install them separately.

Solo developers: this is the easiest way to run Kubernetes locally or on a single VPS. Small teams: production-ready for most workloads. Growing teams: use it. It's the same Kubernetes, just lighter.

The catch: K3s uses SQLite by default instead of etcd, which means single-node setups aren't highly available. For HA, you'll switch to an external Postgres/MySQL database or embedded etcd, which adds complexity back. Also, some enterprise Kubernetes tools assume full K8s and might not work out of the box.