Create a base image

So you want to create your own Base Image? Great!

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, you‘ll want to start with a working machine that is running the distribution you’d like to package as a base image, though that is not required for some tools like Debian's Debootstrap, which you can also use to build Ubuntu images.

It can be as simple as this to create an Ubuntu base image:

$ sudo debootstrap raring raring > /dev/null
$ sudo tar -C raring -c . | docker import - raring
a29c15f1bf7a
$ docker run raring cat /etc/lsb-release
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=13.04
DISTRIB_CODENAME=raring
DISTRIB_DESCRIPTION="Ubuntu 13.04"

There are more example scripts for creating base images in the Docker GitHub Repo:

• BusyBox
• CentOS / Scientific Linux CERN (SLC) on Debian/Ubuntu or on CentOS/RHEL/SLC/etc.
• Debian / Ubuntu

Creating a simple base image using scratch

There is a special repository in the Docker registry called scratch, which was created using an empty tar file:

$ tar cv --files-from /dev/null | docker import - scratch

which you can docker pull. You can then use that image to base your new minimal containers FROM:

FROM scratch
COPY true-asm /true
CMD ["/true"]

The Dockerfile above is from an extremely minimal image - tianon/true.

More resources

There are lots more resources available to help you write your 'Dockerfile`.

• There's a complete guide to all the instructions 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.
• If your goal is to create a new Official Repository, be sure to read up on Docker's Official Repositories.