Container Registry is a service for storing, versioning, and distributing container images (the packaged app filesystem plus configuration) so tools like Docker and platforms like Kubernetes can pull the exact artifact to run. It addresses the challenge of moving a single, consistent build output from CI into multiple environments while enforcing who can publish and deploy. At a high level, build pipelines push images to the registry using readable tags (like app:1.4) and immutable digests (content-based IDs), and runtime nodes pull them on demand; most registries also handle authentication and authorization, retention and cleanup, and vulnerability scanning.
With a Container Registry, releases are repeatable and auditable because every environment fetches the same image, while without it teams often rebuild or share images informally, increasing drift, rollout failures, and supply chain risk. This gap exists because images are large binary artifacts that need consistent addressing, caching, and access control across many machines and clusters.