documentation: what to do on "Created API client, waiting for the control plane to become ready"

[alban]

kube-spawn can block on:

[apiclient] Created API client, waiting for the control plane to become ready

The troubleshooting.md documentation should suggest ideas how to debug this, such as:

sudo machinectl shell kube-spawn-0
systemctl status kubelet
journalctl -u kubelet

In my case, it failed because of:

Sep 22 16:08:26 kube-spawn-0 kubelet[1194]: unknown flag: --fail-swap-on