SmartOS
SmartOS is an open-source UNIX-like operating system based on illumos, a community fork of OpenSolaris. It features four technologies - ZFS (a combined file system and logical volume manager), DTrace (a dynamic tracing framework for troubleshooting kernel and application problems), Zones (a lightweight virtualisation solution), KVM and bhyve (two full virtualisation solutions for running a variety of guest operating systems, including Linux, Windows, BSD and Plan9).
Talos Linux
Talos is a specialist Linux-based operating system for running Kubernetes, an open-source system for automating deployment, scaling and management of containerised applications. Minimal, immutable and hardened, it does not offer any shell or interactive console; instead, all system management is done via remote Application Programming Interface (API) calls, where messages sent from a client application are protected with mutual Transport Layer Security TLS (mTLS) authentication.