Container Runtime
In plain terms
The software that actually runs containers.
Going deeper
A container runtime pulls images and creates, runs, and manages containers using OS isolation features. It's the engine beneath orchestrators.
Under the hood
Kubernetes talks to runtimes (containerd, CRI-O) via the Container Runtime Interface (CRI).
Examples
containerd, CRI-O, runc, the layer beneath Docker/Kubernetes.
Think of it like...
Like the engine that turns the container blueprint into a running machine.