PiCluster: Simple Container Orchestration
github.com
github.com
Kubernetes and nomad are a bear to get started with in comparison.
Seriously, if you want Kubernetes, look at just deploying openshift, there's ansible playbooks out there and even an installer to write the ansible inventory on your behalf to make it super easy, and the OpenVSwitch configuration is just magic compared to getting flannel set up right for k8s.
I'm not sure that it can run on the Raspberry Pi, but it is definitely worth a try.