šŸŽ™ļø Discussion

Tar flavor


Table of contents

  1. What are the challenges that we are trying to solve?
  2. What ideas do we have for how to address these challenges?
  3. How do these ideas break down intoā€¦
    1. Already existing OCI specs?
    2. A new project (CNCF or OCI)
  4. Questions?
  5. What pre-existing work or software can support these ideas?
  6. Relevant OCI Issues

What are the challenges that we are trying to solve?

Tar has several flavors, including old POSIX, new POSIX (PAX), GNU, UStar, and Schily; another issue is whether or not layer should be tarbombs (in practice they seem to be). The spec seems aware of this, but lacks any discussion of which flavors are and are not supported.

Aleksa Sarai has written a detailed history of tar in his critique of tarball layers.

What ideas do we have for how to address these challenges?

Amend the spec to document what tar formats and features are supported.

How do these ideas break down intoā€¦

Already existing OCI specs?

Image spec.

A new project (CNCF or OCI)

Questions?

What pre-existing work or software can support these ideas?

Relevant OCI Issues

Someone proposed ustar in 2016 (issue #342). The response started as ā€œThis is a bit excessive. Honestly iā€™m inclined to just close this.ā€ and more or less ended the same way. Note this discussion claims that the ā€œdocsā€ call for ā€œGNU tar ā€˜standardā€™ formatā€, but I was not able to find anything to this effect in the image spec.