Docker-Docs/develop/develop-images/baseimages.md

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2020-11-18 13:32:27 -05:00
---
description: How to create base images
keywords: images, base image, examples
redirect_from:
- /engine/articles/baseimages/
- /engine/userguide/eng-image/baseimages/
title: Create a base image
---
Most Dockerfiles start from a parent image. If you need to completely control
the contents of your image, you might need to create a base image instead.
Here's the difference:
- A [parent image](../../glossary.md#parent_image) is the image that your
image is based on. It refers to the contents of the `FROM` directive in the
Dockerfile. Each subsequent declaration in the Dockerfile modifies this parent
image. Most Dockerfiles start from a parent image, rather than a base image.
However, the terms are sometimes used interchangeably.
- A [base image](../../glossary.md#base_image) has `FROM scratch` in its Dockerfile.
This topic shows you several ways to create a base image. The specific process
will depend heavily on the Linux distribution you want to package. We have some
examples below, and you are encouraged to submit pull requests to contribute new
ones.
## Create a full image using tar
In general, start with a working machine that is running
the distribution you'd like to package as a parent image, though that is
not required for some tools like Debian's
[Debootstrap](https://wiki.debian.org/Debootstrap), which you can also
use to build Ubuntu images.
It can be as simple as this to create an Ubuntu parent image:
$ sudo debootstrap xenial xenial > /dev/null
$ sudo tar -C xenial -c . | docker import - xenial
a29c15f1bf7a
$ docker run xenial cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=16.04
DISTRIB_CODENAME=xenial
DISTRIB_DESCRIPTION="Ubuntu 16.04 LTS"
There are more example scripts for creating parent images in the Docker
GitHub Repo:
- [BusyBox](https://github.com/moby/moby/blob/master/contrib/mkimage/busybox-static)
- CentOS / Scientific Linux CERN (SLC) [on Debian/Ubuntu](
https://github.com/moby/moby/blob/master/contrib/mkimage/rinse) or
[on CentOS/RHEL/SLC/etc.](
https://github.com/moby/moby/blob/master/contrib/mkimage-yum.sh)
- [Debian / Ubuntu](
https://github.com/moby/moby/blob/master/contrib/mkimage/debootstrap)
## Create a simple parent image using scratch
You can use Docker's reserved, minimal image, `scratch`, 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 the hub, 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`:
```dockerfile
FROM scratch
ADD hello /
CMD ["/hello"]
```
Assuming you built the "hello" executable example by following the instructions
at
[https://github.com/docker-library/hello-world/](https://github.com/docker-library/hello-world/),
and you compiled it with the `-static` flag, you can build this Docker
image using this `docker build` command:
```bash
docker build --tag hello .
```
Don't forget the `.` character at the end, which sets the build context to the
current directory.
> **Note**: Because Docker Desktop for Mac and Docker Desktop for Windows use a Linux VM,
> you need a Linux binary, rather than a Mac or Windows binary.
> You can use a Docker container to build it:
>
> ```bash
> $ docker run --rm -it -v $PWD:/build ubuntu:16.04
>
> container# apt-get update && apt-get install build-essential
> container# cd /build
> container# gcc -o hello -static -nostartfiles hello.c
> ```
To run your new image, use the `docker run` command:
```bash
docker run --rm hello
```
This example creates the hello-world image used in the tutorials.
If you want to test it out, you can clone
[the image repo](https://github.com/docker-library/hello-world).
## More resources
There are lots of resources available to help you write your `Dockerfile`.
* There's a [complete guide to all the instructions](../../engine/reference/builder.md) available for use in a `Dockerfile` in the reference section.
* To help you write a clear, readable, maintainable `Dockerfile`, we've also
written a [`Dockerfile` best practices guide](dockerfile_best-practices.md).
* If your goal is to create a new Official Image, be sure to read up on Docker's [Official Images](../../docker-hub/official_images.md).