Base Images: Definition and Creation

--- title: Base images weight: 70 description: Learn about base images and how they're created keywords: images, base image, examples aliases: - /articles/baseimages/ - /engine/articles/baseimages/ - /engine/userguide/eng-image/baseimages/ - /develop/develop-images/baseimages/ --- All Dockerfiles start from a base image. A base is the image that your image extends. It refers to the contents of the `FROM` instruction in the Dockerfile. ```dockerfile FROM debian ``` For most cases, you don't need to create your own base image. Docker Hub contains a vast library of Docker images that are suitable for use as a base image in your build. [Docker Official Images](../../docker-hub/image-library/trusted-content.md#docker-official-images) have clear documentation, promote best practices, and are regularly updated. There are also [Docker Verified Publisher](../../docker-hub/image-library/trusted-content.md#verified-publisher-images) images, created by trusted publishing partners, verified by Docker. ## Create a base image If you need to completely control the contents of your image, you can create your own base image from a Linux distribution of your choosing, or use the special `FROM scratch` base: ```dockerfile FROM scratch ``` The `scratch` image is typically used to create minimal images containing only just what an application needs. See [Create a minimal base image using scratch](#create-a-minimal-base-image-using-scratch). To create a distribution base image, you can use a root filesystem, packaged as a `tar` file, and import it to Docker with `docker import`. The process for creating your own base image depends on the Linux distribution you want to package. See [Create a full image using tar](#create-a-full-image-using-tar). ## Create a minimal base image using scratch The reserved, minimal `scratch` image serves as a starting point for building containers. Using the `scratch` image signals to the build process that you want the next command in the `Dockerfile` to be the first filesystem layer in your image. While `scratch` appears in Docker's [repository on Docker Hub](https://hub.docker.com/_/scratch), you can't pull it, run it, or tag any image with the name `scratch`. Instead, you can refer to it in your `Dockerfile`. For example, to create a minimal container using `scratch`:

A base image is the foundation upon which a Docker image is built, specified by the `FROM` instruction in a Dockerfile. While many suitable base images are available on Docker Hub, users can create custom base images using a Linux distribution or the special `scratch` image for minimal containers. This section provides guidance on creating base images, including using `scratch` and importing root filesystems.