`kubelet` - the node agent (run by systemd as kubelet.service)

kubelet --version

Options you will use

--version: the installed binary version

Examples

$ systemctl status kubelet

is it running

$ journalctl -u kubelet -n 50 --no-pager

why it is not

Gotchas

Config: /var/lib/kubelet/config.yaml (KubeletConfiguration), flags: /var/lib/kubelet/kubeadm-flags.env, kubeconfig: /etc/kubernetes/kubelet.conf.
Before kubeadm init/join the kubelet crash-loops every 10s waiting for its config - that is expected.

Try kubelet in a real terminal Free, in your browser - a real Ubuntu terminal to try it in, with missions that check your work.