Pod Disruption Budgets (PDBs) were introduced to protect against voluntary disruptions. What is their primary function?

• A. Ensuring automatic node provisioning
• B. Maintaining a minimum number of available replicas during voluntary disruptions
• C. Preventing node failures from affecting Pods
• D. Balancing Pods across Availability Zones

Answer: (B)

Pod Disruption Budgets regulate how many pods can be evicted during voluntary disruptions so the application stays up. The primary function is to maintain a minimum number of available replicas when maintenance actions occur, such as node drains or rolling updates. PDBs define a threshold via minAvailable (the smallest number of pods that must remain up) or maxUnavailable (the largest number that can be down). Kubernetes will only evict pods in a way that respects this limit, so if you have, say, five replicas and a minAvailable of four, only one pod can be evicted at a time during the disruption. This protects service continuity while maintenance happens. It’s tied to a group of pods selected by labels (often the pods of a Deployment or StatefulSet) and does not automatically provision nodes, prevent involuntary failures, or balance Pods across Availability Zones.