docker-rsync recursively watches directories for changes and copies changes via rsync. It is a drop in replacement for the existing boot2docker vboxsf feature.
Please note though that syncing happens only in one direction. If you want to sync back from a Docker container to your local machine, docker-rsync is not the tool you're looking for.
Is it fast? Yes! While the initial sync might take some seconds (depending on the number of files you want to sync), following syncs are super fast (compared to vboxsf & NFS). A one file sync usually takes less than 100ms.
docker-rsync relies on FSEvents API, so this tool will only work under Mac OSX.
brew tap synack/docker brew install docker-rsync
Usage with docker-machine
brew install docker-machine docker-machine create my-machine123 -d virtualbox cd sync-this-directory echo ".git" >> .rsyncignore docker-rsync my-machine123
Talk to rsync directly
cd sync-this-directory echo ".git" >> .rsyncignore docker-rsync rsync://<IP:PORT>/<MODULE>