Kured

Kured is an open source tool that allows Kubernetes administrators to control when their Nodes can reboot.

This way, automatic upgrades like unattended-upgrades can be configured in the cluster nodes so the OS dependencies are automatically patched.

When a reboot is necessary, unattended-upgrades will create a file /var/run/reboot-required instead of automatically rebooting the node. Kured runs as a daemon in your Kubernetes cluster and monitors the existing of that file. Once it detects a node needs to be rebooted, kured ensures a single node reboots at a time, and it cordongs & drains the node before rebooting.

In addition, kured lets you define the day of the week and time of the day that your nodes can reboot, as well as delay a reboot based on prometheus alerts and/or pod selectors.

Contribution

Kured can be configured to send a slack notification when draining and rebooting a Node. However the notification message was hardcoded as in Rebooting node %s.

This was limiting for myself, since I was going to use kured in many clusters across different clouds and regions. It would be great if I could send a message like Rebooting node %s, from cluster %s, region %s

I submitted a PR that introduced 2 new options with drain/reboot message formats. I also stayed for the conversation on refactoring the notifications using shouterrr so destinations other than slack are supported.