What does the term 'node affinity' refer to in Kubernetes?

Node affinity in Kubernetes refers to the set of rules used to determine which nodes a pod can be scheduled on based on node labels. This feature helps users define constraints that allow for placing pods on specific nodes based on the labels applied to those nodes. For example, if certain pods need to run on nodes with specific hardware capabilities or geographic locations, node affinity rules can enforce this scheduling behavior.

By leveraging node affinity, administrators can optimize workloads, improve resource allocation, and ensure that applications meet their operational requirements regarding the underlying infrastructure. This flexibility is essential for managing diverse workload needs, particularly in complex environments where specific node characteristics matter for application performance or compliance.

In contrast, the other options refer to different Kubernetes functionalities that do not relate directly to the concept of node affinity. Resource configuration, system upgrades, and high availability all play significant roles in Kubernetes operations but do not describe the targeted scheduling rules that node affinity provides.