fix(vagrant): use rsync for shared folders

[bacongobbler]

In terms of stability, nfs seems to drop the mount every so often, which is not good for development. running vagrant rsync to synchronize changes between the server and the host machine will not have any missing mount issues, so let's switch over to rsync.

fixes #752

[carmstrong]

A caveat of this is that changes on the local filesystem won't appear on the VM until you poke vagrant to re-rsync. It may be worth exploring a change to the NFS mount first - specifically, allowing it to use TCP instead of UDP (kind of a stab in the dark, but is worth checking out).

[bacongobbler]

True. This change will not allow automagic synchronization between the host and the server, but if there's a way to get NFS working nicely without randomly dropping the mount then I'm all ears. :)

[carmstrong]

http://docs.vagrantup.com/v2/synced-folders/nfs.html

I was thinking of setting nfs_udp: false and removing the specific mount options we're setting and allowing vagrant to set its defaults. But this isn't something I've spent much time debugging yet.

[bacongobbler]

Until that BTRFS restart issue is resolved, I'd still argue that rsync is the way to go for the time being. :)

[carmstrong]

I'm still not convinced that every time the mount has dropped it's been due to a reboot, as I have connected immediately afterward. My gut tells me there is something else at work here that I can debug at a systems level... but without much more to go on, if this fixes it for now, I'm fine with that. We should revisit it after teh btrfs bug is fixed, though. LGTM.

[mboersma]

We should also make the same change to contrib/vagrant/Vagrantfile then, and update docs/contributing/localdev.rst where we mention NFS and being asked for a password.

[bacongobbler]

I changed the docs to reflect it, but it seems like such a small blip that most people are going to miss it. What can I do to make it more "visible"? I could add a "Make Changes" subheading and add docs there.

[mboersma]

WRT making the need to rsync more obvious: maybe one of those Note: callout sections like at http://docs.deis.io/en/latest/developer/buildpack/#adding-custom-buildpacks ? And / or a code-block section of doing vagrant rsync.

[bacongobbler]

done.

[gabrtv]

I'm a big -1 on requiring a manual rsync. Plus I'm not convinced NFS is the root issue here. Let's let things stabilize in Vagrant-land before we move on this.

[carmstrong]

Should we close this as a no-fix for now?

[bacongobbler]

Sure. It doesn't really matter which path we take since we are hitting nfs unmount issues with coreos/coreos-vagrant#68, which is the root reason why this PR came to be. Let's close as a wontfix for now.