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 -