Ready to use lab environment with VirtualBox and Vagrant

Hi,

In case anyone would like to practice course labs on their own virtual environment here is a quick way to setup an initial infrastructure with Virtualbox and Vagrant: https://github.com/michalgutowski/cka-lab

I slightly modified the initial kubeadm-config.yaml because each vm has two network interfaces: one for NAT network and second one for host-only network.

I also changed the initial calico.yaml to make sure calico is using the right network interface (host-only network) and changed the CALICO_IPV4POOL_CIDR to 10.244.0.0/16 because the 192.168.0.0/16 used in the course labs was clashing with my host-only network addressing.

Have fun!
Michal