@fox
CoreOS doesn't actually support the Virtualbox guest additions. Using these requires not only an additional Kernel module, but one which is not upstreamed into the Linux Kernel. We (CoreOS) worked with one of the Kernel developers to try and have this put into the staging kernel tree but there was too many problems with the code for this to be feasible.
The shared folder support that you are seeing is through a Kernel module provided by the Plan 9 filesystem (9pfs) which emulates a squashfs filesystem.
The reason that these are not persisting is the version of the CoreOS image that you are using at the moment. In your Vagrantfile, change the string amd64-generic
to amd64-usr
. This is a new development image that we are working on.
Additionally, make sure you run a git pull
on the repository to ensure you have the most up to date copy of the files. There have been a number of changes since you posted the question and we would hate to see you miss out on them.