A Node is a worker machine in Kubernetes. A node may be a VM or physical machine, depending on the cluster. Each node has the services necessary to run Pods and is managed by the master components.
The nodes of the cluster are listed on the nodes section:
Clicking on a Node a detailed view of the Node appears:
A Node can be (un)cordoned using the Cordon button. Once the node is cordoned the Ready state of the Node is set to false.
Make sure to uncordon the Node before continuing. A Cordoned node doesn't accept new Pod requests.