StatefulSets for stateful applications in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define a StatefulSet with the correct API version.

Kubernetes

apiVersion: apps/[1]
kind: StatefulSet
metadata:
  name: web
spec:
  selector:
    matchLabels:
      app: nginx
  serviceName: "nginx"
  replicas: 3
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx:1.15.4

Drag options to blanks, or click blank then click option'

Av1

Bv1beta1

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'v1' directly without 'apps/' prefix

Using 'core/v1' which is for Pods and Services

The correct API version for StatefulSet is apps/v1.

2fill in blank

medium

Complete the code to specify the volumeClaimTemplates section for persistent storage.

Kubernetes

volumeClaimTemplates:
- metadata:
    name: [1]
  spec:
    accessModes: ["ReadWriteOnce"]
    resources:
      requests:
        storage: 1Gi

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Apersistent

Bstorage

Cvolume

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'storage' which is a resource request, not a name

Using 'persistent' which is not a typical volume claim name

The name under volumeClaimTemplates is typically called data to represent the persistent volume claim for the pod.

3fill in blank

hard

Fix the error in the selector section to correctly match the pod labels.

Kubernetes

selector:
  matchLabels:
    app: [1]

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Anginx

Bnginx-app

Capp

Dweb

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different label value than the pod template

Using the key instead of the value

The selector must match the label used in the pod template. Here, the pod label is app: nginx, so the selector should match nginx.

4fill in blank

hard

Fill both blanks to complete the container volume mount and volume claim reference.

Kubernetes

containers:
- name: nginx
  image: nginx:1.15.4
  volumeMounts:
  - name: [1]
    mountPath: [2]

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Adata

B/usr/share/nginx/html

C/var/lib/data

Dstorage

Attempts:

3 left

💡 Hint

Common Mistakes

Mismatching volumeMount name and volumeClaimTemplates name

Using an incorrect mountPath for nginx

The volumeMount name must match the volumeClaimTemplates name, which is 'data'. The mountPath is the directory inside the container where the volume is mounted, commonly /usr/share/nginx/html for nginx.

5fill in blank

hard

Fill all three blanks to complete the StatefulSet spec with replicas, serviceName, and pod label.

Kubernetes

spec:
  replicas: [1]
  serviceName: "[2]"
  template:
    metadata:
      labels:
        app: [3]

Drag options to blanks, or click blank then click option'

Aweb

B3

Cnginx

Dfrontend

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string for replicas instead of a number

Mismatching serviceName and pod labels

The number of replicas is 3 for three pods. The serviceName is 'nginx' to match the headless service. The pod label 'app' is set to 'nginx' to match the selector.