Kured (KUbernetes REboot Daemon) is a Kubernetes daemonset that
performs safe automatic node reboots when the need to do so is
indicated by the package management system of the underlying OS.

- Watches for the presence of a reboot sentinel e.g. /var/run/reboot-required

- Utilises a lock in the API server to ensure only one node reboots at a time

- Optionally defers reboots in the presence of active Prometheus alerts

- Cordons & drains worker nodes before reboot, uncordoning them after