rebase-docker-image

rebase-docker-image

Rebase a dockerized Windows app to a newer Windows Docker base image.

Introduction

This repo started just for fun to see if it's possible to swap the Windows base images of existing apps on the Docker Hub.

Use cases

• Easily apply Windows Updates to an existing Windows app in seconds.
• Make images usable again that you have built with Insider.
• Provide your app for all available Windows Update layers to avoid download.
• Sync multiple images based on different Windows Update layers to the current.
• Create images for Server 1709 without having a machine for it.
• The tool can also be used on Linux as no images have to be pulled.

Limits

• You cannot move an app from a windowsservercore image to the nanoserver image.
• You cannot rebase windowsservercore image with RUN instructions to 1709. Only COPY and ENV seem to be fine.
• You also cannot move PowerShell scripts into the 1709 nanoserver image as there is no PowerShell installed.
• Be warned that this tool may create corrupt images.

Installation

npm install -g rebase-docker-image

Usage

C:\> rebase-docker-image -h
Usage: rebase-docker-image src -t target -b base

It also needs two environment variables DOCKER_USER and DOCKER_PASS to push the target image.

Example

Nanoserver 2016 -> 1709

Let's modernize or update golang from the 10.0.14393.x base image to the 1709 variant.

$ rebase-docker-image \
    golang:1.9-nanoserver \
    -t stefanscherer/golang-windows:1.9-nanoserver-1709 \
    -b microsoft/nanoserver:1709

Nanoserver 2016 -> Insider 17035

Let's modernize or update winspector from the 10.0.14393.x base image to the Insider 17035 variant.

$ rebase-docker-image \
    stefanscherer/winspector:windows-2.0.0-2016 \
    -s microsoft/nanoserver:10.0.14393.1770 \
    -t stefanscherer/winspector:insider-17035 \
    -b microsoft/nanoserver-insider:10.0.17035.1000

Changing from a different base image repo to another we have to specify with -s the source base image repo and tag. In this case the two base image layers are replaced by the single insider base image layer.

Run it in a container

Windows

docker run -it -e DOCKER_USER -e DOCKER_PASS stefanscherer/node-windows:1709 cmd
npm install -g rebase-docker-image
rebase-docker-image -h

Linux

docker run -it -e DOCKER_USER -e DOCKER_PASS node bash
npm install -g rebase-docker-image
rebase-docker-image -h

Contributing

This tool is in an early stage and many things can be improved.

• Add unit tests, as said it was a Proof of Concept
• Support the ~/.docker/config.json auth or the keychain
• Rewrite it to Golang
• ...

License

MIT