Kured (KUbernetes REboot Daemon) is a DaemonSet that reboots Kubernetes nodes safely when the underlying OS signals that a reboot is required. It was created by Weaveworks and is now a CNCF sandbox project.
The daemon runs on every node and watches for a sentinel — by default the file /var/run/reboot-required that Debian and Ubuntu write after a kernel or glibc upgrade — or the result of a configurable sentinel command for other distributions. When a reboot is needed, kured takes a cluster-wide lock via an annotation on a DaemonSet object so only one node reboots at a time, cordons the node, drains its pods, and then triggers a systemd reboot. After the node comes back it uncordons itself and releases the lock. Reboots can be gated on a maintenance window, the absence of firing Prometheus alerts, or the absence of pods matching a selector, so rollouts pause automatically when the cluster is unhealthy.
Kured is the standard answer for “I enabled unattended-upgrades on my nodes, now what?” and pairs naturally with tools like system-upgrade-controller, which handles the package updates themselves.
