Kubernetes Storage

Pods are ephemeral. When a pod restarts, everything written to its filesystem is gone. PersistentVolumes (PV) and PersistentVolumeClaims (PVC) solve this by decoupling storage from the pod lifecycle, so data survives restarts, rescheduling, and scaling events. This article explains how PVs, PVCs, and StorageClasses work together, what each lifecycle phase means, and where the common misconceptions hide.

Dynamic volume provisioning lets Kubernetes create cloud storage on demand when a pod needs it. Instead of manually pre-creating disks, you define a StorageClass that tells the cluster which CSI driver to call and what parameters to pass. This guide covers the correct CSI driver, StorageClass configuration, and WaitForFirstConsumer binding for EKS (AWS), GKE (GCP), and AKS (Azure).

Velero gives Kubernetes operators application-level backup and restore: namespace-scoped protection, scheduled backups to object storage, volume snapshots, and cross-cluster migration. This tutorial walks through the full lifecycle, from installing Velero and taking your first backup to scheduled retention policies, database consistency hooks, restore operations, and production monitoring.

ConfigMaps decouple configuration from container images, but updating a running application is not as straightforward as editing the ConfigMap. Environment variables never update without a pod restart. Volume mounts do, but only if you avoid subPath and your application actively re-reads the files. This guide covers every consumption pattern, their update semantics, and the tools that close the gaps.