What is the primary purpose of Pod Disruption Budgets in Kubernetes?

• A. They enforce a hard cap on the number of pods.
• B. They ensure a minimum number of pods are always running during voluntary disruptions.
• C. They monitor pod CPU usage.
• D. They govern network isolation.

Answer: (B)

Pod Disruption Budgets define how many pods must stay available during voluntary disruptions, such as maintenance or rolling updates. By setting a minimum number of available pods (minAvailable) or a maximum number that can be disrupted (maxUnavailable), they tell the system how many pods you’re willing to evict at once. During a voluntary disruption, the API server will only evict pods up to that limit; if evicting more would violate the budget, the disruption is blocked or delayed until enough pods are back online or the disruption ends. For example, with five replicas and a minAvailable of four, only one pod can be evicted at a time. This concept is about maintaining availability during planned changes, not about CPU monitoring or network isolation, and it doesn’t stop involuntary outages. That’s why the primary purpose is to ensure a minimum number of pods remain running during voluntary disruptions.