Docker Support

For content of type docker_image and docker_blob, it would be useful for us to have MD5 checksums generated on import and available on the unit thereafter, so that we can check consistency of shipped content in conjunction with tools only supporting MD5.

Here are some more details about the use-case:

- We use pulp_docker to manage docker content for publish.
- We (will) use docker_rsync_distributor to publish docker content to a remote CDN.
- We want to implement a consistency check to verify that data on our CDN is identical to the source data in Pulp (e.g. has not been corrupted after or during publish).
- Our CDN provides a lightweight method to fetch the checksum of a file without downloading it (as an HTTP header), but this only supports MD5.

The CDN is a third-party service and it might be impractical to have that improved with support for other checksum types such as SHA256.

Having the MD5 checksums would allow us to implement consistency checks which compare the checksum reported by our CDN to the checksum stored in Pulp.