What is Container Image?
A read-only template with layers used to create containers.
A container image is an immutable, layered filesystem snapshot that contains everything needed to run an application: code, runtime, libraries, and config. Images are built from a Dockerfile using instructions that each create a new layer. Layers are cached and reused, making builds fast. Images are stored in container registries (Docker Hub, ECR, GHCR). The OCI Image Spec defines the standard format.
Deep Dive Guide
what is a container registry explained
Related Terms
More Containers Terms
BuildKit
Next-generation Docker image build engine with parallel builds and better caching.
Container
A lightweight, isolated process that packages code and its dependencies together.
Container Registry
A repository for storing, versioning, and distributing container images.
Dockerfile
A text file with instructions for building a container image layer by layer.
Docker Compose
A tool for defining and running multi-container Docker applications using YAML.
Multi-stage Build
A Dockerfile pattern using multiple FROM stages to create smaller, leaner final images.
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