Kubernetes is a system for managing containerized applications across multiple machines that was inspired by Google's internal Borg system but is designed to be portable, scalable, and self-healing. Some key concepts in Kubernetes include pods (groups of tightly coupled containers), labels and selectors (for grouping objects), replication controllers (to maintain availability), and services (for exposing pods). Kubernetes handles tasks like scheduling, health checking, and orchestrating updates seamlessly through its declarative API and control loops.