Docker pull into a save

This containerizes the docker pull and outputs a tar file suitable for 'docker load'.

Uses:

• Containerizing the public network-facing portions of Docker pulls
• Support pulling from insecure registries on unmodified Docker Engines
• Support image format changes on older Docker Engine releases (the save/load format has not changed as commonly as the registry API)

Typical Usage

Command:
 $ docker run ewindisch/docker-pull ewindisch/trinity | docker load

This command containerizes the pulling of a container, with loading and extracting of the tar files on the host's docker daemon.

It's not incredibly efficient as tar files are extracted and recreated locally. However, malicious tar file extraction is contained, with a known Docker Engine creating the tar files to be extracted on the host.

A malicious attacker could still exploit the nested Docker daemon which performs the network traffic, but this makes an attack more complex.

Pulling from Insecure Registries

This image may be useful for pulling from an insecure registry without reconfiguring the Docker Engine.

Pulling from an insecure registry may be performed with:

 $ docker run ewindisch/docker-pull --insecure-registry 10.0.0.0/16 10.0.1.2/someimage | docker load

A shortcut for allowing all registries over HTTP is available:

 $ docker run ewindisch/docker-pull --insecure 10.0.1.2/someimage | docker load

It is NOT advised to use the insecure registry feature as it allows man-in-the-middle attacks against your infrastructure.