Add VOLUME instruction to buildfile

[crosbymichael]

Add the VOLUME instruction to the Dockerfile builder.

FROM ubuntu
VOLUME ["/data"]

OR

FROM ubuntu
VOLUME /data

[shykes]

Hey @crosbymichael, thanks for contributing this. Would you mind adding a test which makes sure that the built image does indeed expose a volume at the given path? Your test does verify that the keyword doesn't cause a build to fail, but that's currently the case for all keywords since they are ignored by default.

Happy to help, and looking forward to merging this.

[crosbymichael]

Thanks for the feedback. Done!

[vieux]

@crosbymichael could you rebase to master ? tests are broken.

Thanks

[shykes]

LGTM

[creack]

LGTM

[matthewmueller]

Is volume host:container supported? Or volume [host:container]?

I wasn't able to get that working.

[crosbymichael]

@matthewmueller no, host mounts are not supported in the Dockerfile

[matthewmueller]

@crosbymichael should they be? It seems like an asymmetry between the CLI and the Dockerfile.

[crosbymichael]

No. Dockerfiles should be portable.

On Saturday, August 17, 2013, Matthew Mueller wrote:

@crosbymichael https://github.com/crosbymichael should they be? It
seems like an asymmetry between the CLI and the Dockerfile.

—
Reply to this email directly or view it on GitHubhttps://github.com//pull/1124#issuecomment-22824254
.

Thanks,

---

Michael Crosby
812-250-6603
crosby.michael@gmail.com

[matthewmueller]

Oh good point, so it seems like VOLUME is more to serve volumes-from then because an empty volume inside a container isn't very useful