Kubernetes StatefulSet滚动更新与存储扩容实践

概述目标：在有状态应用中安全地进行滚动更新与在线存储扩容，避免数据损坏与服务中断。适用：数据库、消息队列、缓存集群等。核心与实战存储类允许扩容（StorageClass）：apiVersion: storage.k8s.io/v1

kind: StorageClass

metadata:

name: fast-ssd

provisioner: kubernetes.io/aws-ebs

allowVolumeExpansion: true

reclaimPolicy: Retain

volumeBindingMode: WaitForFirstConsumer

StatefulSet定义：apiVersion: apps/v1

kind: StatefulSet

metadata:

name: db

namespace: prod

spec:

serviceName: db-headless

replicas: 3

updateStrategy:

type: RollingUpdate

selector:

matchLabels: { app: db }

template:

metadata:

labels: { app: db }

spec:

containers:

- name: db

image: repo/db:1.2.3

volumeMounts:

- name: data

mountPath: /var/lib/db

volumeClaimTemplates:

- metadata:

name: data

spec:

accessModes: [ "ReadWriteOnce" ]

storageClassName: fast-ssd

resources:

requests:

storage: 50Gi

PVC扩容步骤：kubectl -n prod get pvc | select-string -pattern db-data

kubectl -n prod patch pvc db-data-db-0 -p '{"spec":{"resources":{"requests":{"storage":"100Gi"}}}}'

kubectl -n prod patch pvc db-data-db-1 -p '{"spec":{"resources":{"requests":{"storage":"100Gi"}}}}'

kubectl -n prod patch pvc db-data-db-2 -p '{"spec":{"resources":{"requests":{"storage":"100Gi"}}}}'

示例有序滚动更新：kubectl -n prod rollout restart statefulset/db

kubectl -n prod rollout status statefulset/db

检查卷大小与节点：kubectl -n prod describe pvc db-data-db-0 | findstr -i capacity

验证与监控应用健康：使用`readinessProbe/livenessProbe`确保滚动期间就绪与健康；观察副本逐个更新。存储后端：验证后端卷支持在线扩容；观察扩容完成事件与文件系统调整。数据一致性：在应对扩容前进行快照/备份；扩容后校验数据完整性。常见误区StorageClass未开启`allowVolumeExpansion`导致扩容失败；需提前配置。一次性扩容所有副本导致负载抖动；应逐个PVC扩容并观察。忽视备份与快照；在生产扩容前需制定恢复方案。结语通过有序滚动与存储扩容，StatefulSet可在生产中保持稳定升级与容量提升，并以验证与监控保障数据安全。