kubernetes

Kubernetes StatefulSet Generator

Generate a Kubernetes StatefulSet YAML with a PVC template and headless Service. Ready for databases, queues, and other stateful workloads.

Generator

Inputs

App Name

Namespace

Container Image

Replicas

Container Port

Storage Size per Pod

e.g. 5Gi, 20Gi, 100Gi

Storage Class

Volume Mount Path

CPU Request

Memory Request

CPU Limit

Memory Limit

Output — statefulset.yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: my-app
  namespace: default
  labels:
    app: my-app
spec:
  serviceName: "my-app-headless"
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
        - name: my-app
          image: my-app:latest
          imagePullPolicy: IfNotPresent
          ports:
            - containerPort: 8080
              name: app
          volumeMounts:
            - name: data
              mountPath: /data
          resources:
            requests:
              cpu: 100m
              memory: 128Mi
            limits:
              cpu: 500m
              memory: 512Mi
  volumeClaimTemplates:
    - metadata:
        name: data
      spec:
        accessModes: ["ReadWriteOnce"]
        storageClassName: longhorn
        resources:
          requests:
            storage: 10Gi
---
apiVersion: v1
kind: Service
metadata:
  name: my-app-headless
  namespace: default
  labels:
    app: my-app
spec:
  clusterIP: None
  selector:
    app: my-app
  ports:
    - port: 8080
      targetPort: app
      name: app

Kubernetes StatefulSets

StatefulSets provide three guarantees Deployments don't: stable network identities, stable persistent storage, and ordered startup/shutdown.

Pod Identity

my-app-0   — always pod 0, always uses PVC data-my-app-0
my-app-1   — always pod 1, always uses PVC data-my-app-1
my-app-2   — always pod 2, always uses PVC data-my-app-2

DNS for Each Pod

<pod>.<headless-svc>.<namespace>.svc.cluster.local
my-app-0.my-app-headless.default.svc.cluster.local

volumeClaimTemplates

Each pod gets its own PVC. The template generates:

›data-my-app-0 for pod 0
›data-my-app-1 for pod 1

PVCs outlive pods — data persists through pod restarts and rescheduling.

Common Stateful Workloads

App	Replicas	Storage
PostgreSQL (CNPG)	1 primary + N replicas	Longhorn or cloud SSD
Redis Sentinel	3 (1 primary + 2 replicas)	Longhorn
Kafka	3+	Fast local NVMe
Zookeeper	3	Standard SSD

Key Terms

Full glossary →

kubeadm

A tool for bootstrapping Kubernetes clusters. It automates the setup of control plane components and joining worker nodes, following Kubernetes best practices.

etcd

A distributed key-value store used by Kubernetes to store all cluster state and configuration. etcd is the single source of truth for the entire cluster.

cert-manager

A Kubernetes controller for automating TLS certificate management. cert-manager can issue certificates from Let's Encrypt, Vault, or internal CAs, and automatically renews them.

Helm

A package manager for Kubernetes. Helm charts bundle Kubernetes manifests into reusable packages with configurable values, versioned and published to chart repositories.

Frequently Asked Questions

When should I use a StatefulSet vs a Deployment?

Use a StatefulSet when your pods need stable network identities (predictable pod names like my-app-0, my-app-1), stable persistent storage (each pod gets its own PVC that follows it), or ordered startup/shutdown. Databases (PostgreSQL, MongoDB, Redis Sentinel), message queues (Kafka, RabbitMQ), and distributed caches are all StatefulSet use cases. Use a Deployment for stateless apps where any pod is interchangeable.

What is a headless Service and why does a StatefulSet need one?

A headless Service (clusterIP: None) doesn't get a virtual IP. Instead, DNS returns individual pod IPs directly. StatefulSets require a headless Service to create stable DNS entries for each pod: my-app-0.my-app-headless.default.svc.cluster.local. This allows pods to discover and communicate with specific replicas — essential for clustering protocols (Raft, Paxos, Galera).

Can I scale a StatefulSet down safely?

Yes, but with caution. Kubernetes scales down StatefulSets in reverse order (my-app-2 first, then my-app-1, etc.) and respects PodDisruptionBudgets. The PVC is NOT deleted when you scale down — the pod's data persists. If you scale back up, the same PVC is reattached. To delete PVCs you must do it manually. Never scale below quorum for clustered apps (e.g. don't scale an odd-node etcd from 3→2).

How do I update a StatefulSet?

StatefulSets support RollingUpdate (default) and OnDelete strategies. With RollingUpdate, pods are updated one at a time in reverse ordinal order — my-app-2 first. This ensures the cluster always has running nodes during an upgrade. Set partition: N to do a staged rollout where only pods with ordinal ≥ N are updated, letting you test on one pod before rolling to all.

Related Calculators

Longhorn Storage

Related Guides

kubernetes

Kubernetes StatefulSet Generator

Generator

Inputs

Output — statefulset.yaml

Kubernetes StatefulSets

Pod Identity

DNS for Each Pod

volumeClaimTemplates

Common Stateful Workloads

Key Terms

Frequently Asked Questions

When should I use a StatefulSet vs a Deployment?

What is a headless Service and why does a StatefulSet need one?

Can I scale a StatefulSet down safely?

How do I update a StatefulSet?

Related Calculators

Related Guides

CI/CD for Kubernetes with GitHub Actions: A Complete Guide (2026)

ArgoCD vs Flux: Choosing a GitOps Tool for Kubernetes in 2026

Hetzner vs DigitalOcean for Kubernetes in 2026: An Honest Comparison

Generator

Inputs

Output — statefulset.yaml