How to: How do I add a node to my AWS Kubernetes cluster?
If you used `kube-up.sh` or `kops` to provision your cluster, then it created an AutoScaling Group automatically. You can re-scale that with kops, or update the ASG directly, to grow/shrink the cluster. New instances are provisioned for you and should join the cluster automatically (my experience has been it takes 5-7 minutes for nodes to join). 

With `kops` the recommended process is to edit the InstanceGroup (ig) and then update your cluster. `kops` also supports multiple instance groups per cluster so you can have multiple Auto Scaling Groups to run multiple types of instances within your cluster. Spot instances are also supported.