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Orientation brief

06

Image Layers Deep Dive

You've built images. You've seen Docker mention "layers." But what exactly are layers? Why do they matter? Understanding layers is the key to building efficient images. It explains why some images are 50MB and others are 2GB. It explains why builds are sometimes instant and sometimes painfully slow. It explains how containers can start in milliseconds. In this module, we'll peel back the layers (pun intended) and understand how images really work inside.

01

Understand the problem this module is here to solve.

02

Read 5 chapters in order, from context to application.

03

Practice the module concepts through focused exercises.

Chapter route

Read in order

Chapter 6.1 How Layers Work (The Transparent Sheet Analogy)
Chapter 6.2 Copy-on-Write Explained
Chapter 6.3 Layer Caching
Chapter 6.4 Optimizing Dockerfiles for Layers
Chapter 6.5 Multi-Stage Builds

Practice

Module exercises

Move from reading to investigation with scenario-based practice for this module.

Open exercises →

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Reading-first Docker learning: understand, verify, and ship.