The Cluser Autoscaler uses EC2 Auto-Scaling Groups to configure the
instances it launches when it determines additional worker nodes are
necessary. Auto-Scaling Groups have an associated Launch Template,
which describes the properties of the instances, such as AMI ID,
instance type, security groups, etc.
When instances are first launched, they need to be configured to join
the on-premises Kubernetes cluster. This is handled by *cloud-init*
using the configuration in the instance user data. The configuration
supplied here specifies the Fedora packages that need to be installed on
a Kubernetes worker node, plus some additional configuration required by
`kubeadm`, `kubelet`, and/or `cri-o`. It also includes a script that
fetches the WireGuard client configuration and connects to the VPN,
finalizes the setup process, and joins the cluster.
Dustin