Build Cache

How Do Docker Image Layers and Build Caching Work?

Each instruction in a Dockerfile produces an immutable, content-addressed image layer, and Docker’s build cache reuses a previously built layer whenever the in…

How do container image layers work, and why do they matter for build speed?

A container image is a stack of read-only filesystem layers, each produced by one build instruction and identified by a content hash, that a union filesystem o…

What is BuildKit, and how does it improve on the classic Docker builder?

BuildKit is Docker’s modern build engine that replaces the legacy sequential builder with a concurrent, dependency-graph-based system, enabling parallel execut…

What causes cache busting in Docker builds, and how do you avoid it?

Cache busting happens when a Dockerfile instruction’s cache key changes unexpectedly — usually because an earlier layer’s content changed, the instruction itse…