How deeply does Kubernetes in Action, Second Edition cover Dockerfile instruction?

Explains base-image pulls, temporary containers, image layers, and tagging, but gives syntax detail only through one minimal example.

Dockerfile instruction

As explained in Kubernetes in Action, Second Edition

A Dockerfile instruction is a declarative command that specifies one step in building a container image.

A Dockerfile instruction is a declarative command that specifies one step in building a container image. Docker reads the Dockerfile from the build context and processes its instructions through the Docker daemon. section 2.2.2

Listing 2.1 A minimal Dockerfile for building a container image

FROM node:23-alpine      #1
COPY app.js /app.js       #2
COPY html/ /html      #3
ENTRYPOINT ["node", "app.js"]      #4

A minimal Dockerfile combines FROM to select a base image, COPY to add application files, and ENTRYPOINT to define the container process. section 2.2.2

During a build, Docker pulls the base image when needed, creates a temporary container, executes the next instruction, and records the resulting state as an image layer. Processing continues until the final image is tagged. section 2.2.2

Building an image

Run docker build -t kiada:latest . from the directory containing the Dockerfile and application files. The dot supplies the build context; afterward, docker images lists the tagged image and docker history shows instruction-derived layers. section 2.2.2

How Kubernetes in Action, Second Edition covers it

Cover of Kubernetes in Action, Second Edition

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Also explained in

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Learn Docker in a Month of Lunches, Second EditionA Dockerfile instruction is a declarative directive that specifies a build action or image metadata.
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.NET in Action, Second EditionA Dockerfile instruction is a directive written with an instruction keyword and arguments that controls image construction.

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Related concepts

Dockerfilepart of · A Dockerfile is a text file containing declarative instructions for building a container image and specifying its contents and runtime metadata.
image layerproduces · An image layer is an immutable filesystem change set that contributes to a layered container image and may be stored, cached, or shared independently.
healthcheck instructionincludes · The HEALTHCHECK instruction is a Dockerfile instruction that defines a command and scheduling parameters for testing an application's health in a container.
build cacheconfigures · A build cache is a storage mechanism that preserves completed build-task outputs for reuse when the relevant inputs have not changed.
commandcontrasts with · A command is an instruction or request representing an operation for a system or component to interpret, handle, or execute.
copy instructionincludes · The Dockerfile COPY instruction copies files or directories from a build context or another build stage into an image’s filesystem.

This explainer was generated by Manning's knowledge graph from the text of Kubernetes in Action, Second Edition. The section links point to the parts of the book it draws on.