From instruction
The FROM instruction is a Dockerfile directive that selects the base image or empty filesystem for a container image build stage.
.NET in Action, Second Edition
The FROM instruction selects a base image and begins a build stage in a Dockerfile.
- How it is used
- Starts Dockerfile image construction by selecting an existing image for subsequent modifications.
- How deep it goes
- Explains base-image selection, immutability, and multiple stages, then demonstrates SDK-to-runtime image transfer.
- Examples
- Uses .NET 6 SDK and ASP.NET images in single-stage and named multi-stage Dockerfiles.
- What you can do after
- Build it from scratch by selecting .NET base images in a Dockerfile and producing tagged images with docker build.
Read how .NET in Action, Second Edition explains from instruction →
Podman in Action: Secure, rootless containers for Kubernetes, microservices, and more
The FROM directive specifies the base image or empty starting filesystem for a container image build.
- How it is used
- Establishes the filesystem and base layer on which subsequent image-building instructions operate.
- How deep it goes
- Explains required placement, scratch semantics, registry pulls, rootfs mounting, base layers, and multiple build stages.
- Examples
- Demonstrates FROM scratch, registry.access.redhat.com/ubi8, ubi8/httpd-24, and a two-step HTTP application build.
- What you can do after
- Build an image from an empty rootfs or selected base image using Podman and subsequent Containerfile instructions.
Road to Kubernetes
The FROM directive is a Dockerfile instruction that specifies the base container image for a build.
- How it is used
- Uses a prebuilt image to establish the starting environment for repeatable Docker container builds.
- How deep it goes
- Defines inheritance and version tags, but stops short of explaining image internals or advanced Dockerfile behavior.
- Examples
- Demonstrates Ubuntu with NGINX and versioned Python and Node.js runtime images.
- What you can do after
- Build it from scratch by selecting a runtime image and writing its FROM line with an appropriate version tag.
Related concepts
- container imageuses · A container image is a packaged filesystem and configuration artifact from which a container can be created and run.
- base imageuses · A base image is a container image that supplies the initial filesystem and environment from which another container image is built.
- multistage buildused by · A multistage build is a container-image construction technique that uses separate build stages and includes only selected artifacts in the final runtime image.
- Dockerfilepart of · A Dockerfile is a text file containing declarative instructions for building a container image and specifying its contents and runtime metadata.
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