In the README.rst, which is included in the cdk.zip, you're told to download the box image next to the Vagrantfile (into the same folder) and then to launch it via vagrant up.
The README.rst is missing to specifiy though, that the image should be called cdkv2. One finds out with the error that's displayed in the terminal.
Symlinking my cdkv2 -> rhel-7-cdk-vagrant-scratch-7.2.07102016-1.x86_64.vagrant-libvirt.box fixed the issue for me.
In the README.rst, which is included in the cdk.zip, you're told to download the box image next to the Vagrantfile (into the same folder) and then to launch it via vagrant up. The README.rst is missing to specifiy though, that the image should be called cdkv2. One finds out with the error that's displayed in the terminal. Symlinking my cdkv2 -> rhel-7-cdk-vagrant-scratch-7.2.07102016-1.x86_64.vagrant-libvirt.box fixed the issue for me.