vagrant Getting started with vagrant syncing folders but exclude some folders

Example

For syncing all folders in both direction, insert this into your Vagrantfile:

config.vm.synced_folder "my-project1", "/home/vagrant/my-project1", type: "rsync",
 :rsync__exclude => ['my-project1/mini_project2/target,my-project1/mini_project2/target,my-project1/mini_project3/target']

All the target folders are excluded from syncing.
Syncing only happens on vagrant up and on vagrant reload.
To sync every change from you host to guest you have to use:

vagrant rsync-auto