StatefulSet ordering and naming in Kubernetes - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Pod Naming Pattern in StatefulSets

In Kubernetes StatefulSets, what is the correct naming pattern for pods created by a StatefulSet named web with 3 replicas?

A web-0, web-2, web-4

B web-1, web-2, web-3

C web-0, web-1, web-2

D web-01, web-02, web-03

💡 Hint

Pods are named with the StatefulSet name plus a zero-based ordinal index.

StatefulSet pods are named using the StatefulSet name followed by a dash and a zero-based ordinal number starting at 0.

💻 Command Output

intermediate

Pod Creation Order in StatefulSets

What is the order of pod creation when a StatefulSet with 3 replicas is deployed?

Kubernetes

kubectl get pods -l app=web --watch

A web-0, web-1, web-2 in sequence

B All pods created simultaneously

C web-2, web-1, web-0 in sequence

D web-1, web-0, web-2 in sequence

💡 Hint

StatefulSets create pods one by one in order.

StatefulSets create pods sequentially starting from ordinal 0 to the highest ordinal.

🔀 Workflow

advanced

Pod Deletion and Recreation Order

If you delete pod web-1 in a StatefulSet with 3 replicas, what happens next?

A All pods are deleted and recreated

B web-2 is deleted and recreated before web-1

C web-0 is deleted and recreated before web-1

D Only web-1 is recreated immediately

💡 Hint

Pods are managed individually but respect ordinal order on creation.

Deleting a pod causes only that pod to be recreated. StatefulSet does not delete other pods automatically.

❓ Troubleshoot

advanced

Pod Naming Conflict in StatefulSet

You manually create a pod named web-1 in the same namespace as a StatefulSet named web. What problem can this cause?

A The manual pod is automatically adopted by the StatefulSet

B StatefulSet controller cannot create its own web-1 pod, causing a stuck pod

C StatefulSet deletes the manual pod and creates its own

D No problem, StatefulSet ignores manually created pods

💡 Hint

StatefulSet expects to control pods with specific names.

Manually creating a pod with a StatefulSet pod name blocks the StatefulSet controller from creating its pod, causing issues.

✅ Best Practice

expert

Ensuring Stable Network IDs with StatefulSets

Which practice ensures stable network identities for pods in a StatefulSet?

A Use a Headless Service with the same name as the StatefulSet

B Use a ClusterIP Service with selectors matching the StatefulSet

C Use a LoadBalancer Service for external access

D Use a DaemonSet instead of StatefulSet

💡 Hint

Stable network IDs require DNS entries per pod.

A Headless Service without a cluster IP creates DNS entries for each pod, giving stable network IDs matching pod names.