PodDisruptionBudget (PDB) is a Kubernetes resource that limits the number of pods that can be voluntarily disrupted at a time, protecting critical workloads during rolling updates, node maintenance, or cluster autoscaling. Without PDB, a rolling update can accidentally evict all replicas of a stateful service, causing data loss or extended downtime. This article walks through the concept of voluntary vs. involuntary disruptions, how to define minAvailable and maxUnavailable policies, and a step-by-step migration from unconstrained updates to PDB-protected deployments. It also covers common pitfalls like PDB blocking updates when misconfigured, and how to use PDB with cluster autoscaler and node drains. For platform engineers, PDB is a fundamental building block for production-grade Kubernetes operations, enabling safe, predictable pod lifecycle management.
This article explains how PodDisruptionBudget (PDB) prevents data loss and downtime during Kubernetes rolling updates by controlling voluntary evictions. It provides a practical migration path from ad-hoc pod management to policy-driven, ordered pod migration. For platform teams, mastering PDB is essential for maintaining cluster stability under load.