k3s agent with a data-dir
main node
curl -sfL https://get.k3s.io | sh -s - --data-dir /mnt
follower node
find the token one the main node at
sudo cat /var/lib/rancher/k3s/server/token
curl -sfL https://get.k3s.io | INSTALL_K3S_EXEC="agent --server https://<main-server>:6443 --token <token> --data-dir /mnt
" sh -s -