To add more nodes to a Talos Linux cluster, follow the same procedure as when initially creating the cluster:
  • boot the new machines to install Talos Linux
  • apply the worker.yaml or controlplane.yaml configuration files to the new machines
You need the controlplane.yaml and worker.yaml that were created when you initially deployed your cluster. These contain the certificates that enable new machines to join. Once you have the IP address, you can then apply the correct configuration for each machine you are adding, either worker or controlplane. 
  talosctl apply-config --insecure \
    --nodes [NODE IP] \
    --file controlplane.yaml
The insecure flag is necessary because the PKI has not yet been made available to the node. You do not need to bootstrap the new node. Regardless of whether you are adding a control plane or worker node, it will now join the cluster in its role.