Docker Images & Layers

Summary

Docker images are built from a stack of read-only layers, each corresponding to a Dockerfile instruction — understanding layer caching explains why build order matters for speed.

How to Learn This

1Use docker history on an image to see its layer structure.
2Reorder a Dockerfile's instructions to maximize cache reuse on rebuilds.
3Learn why placing frequently-changing instructions (like copying source code) late in the file speeds up builds.

Dockerfile Best Practices

Docker Compose

More topics in Containers & Docker

Docker Fundamentals Dockerfile Best Practices Docker Compose Container Networking Container Volumes & Storage Multi-Stage Builds Container Registries Container Security Basics

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