Configure ufw firewall

[woile]

Goal
Have a more secure cluster.

Context
I was failing to create a cluster and I don't know if it was ufw or not, so for now I've removed it.
The cluster is working now, so it's possible to add this feature.

Proposal

• Add ufw to the install dependencies in the template yaml.
• Find a way to run all of this:

ufw --force reset  # ok
ufw allow ssh
ufw allow 6443 # Kubernetes API (master)
ufw allow 80  # HTTP
ufw allow 443  # HTTPS
ufw allow 8443  # kubectl proxy
ufw allow 10250  # Kubelet API (master and worker)
ufw allow 10251  # kube-scheduler (master)
ufw allow 10252  # kube-controller-manager (master)
ufw allow 2379:2380/tcp  # etcd server client API (master)
ufw allow 30000:32767/tcp  # NodePort Services** (worker)
ufw default deny incoming
yes | ufw enable

• Find which other ports should be opened

Extras:

WeaveNet

TCP 6783 and UDP 6783/6784