document oldest docker version supported

[egernst]

Version 1.13 docker does not work. We should document the minimal version supported.

[egernst]

/cc @jcvenegas @chavafg @jodh-intel @grahamwhaley - do you recall the minimal version?

[jodh-intel]

Yes - the oldest Docker version we claim to work with is 1.12.1 which is documented in the versions database:

• https://github.com/kata-containers/runtime/blob/master/versions.yaml#L137.

Some users have been having success with Docker 1.11 though:

• make sure kataAgent/createContainer can decode old specs.Spec runtime#334

I'd recommend updating https://github.com/kata-containers/documentation/blob/master/Developer-Guide.md#requirements-to-build-individual-components to point the users at the very human-readable YAML file to avoid hard-coding the version number in another location.

[jodh-intel]

Given you're saying 1.13 doesn't work, it looks like we'll have to investigate why 1.11 and 1.12 work (or used to), but 1.13 does not.

[egernst]

ACK - I'll try to get more details from the person who had the issue here at the hackathon. I didn't see where the limitation/last version was defined - thanks for pointing it out.