Why scheduling controls Pod placement in Kubernetes - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to specify the node selector for a Pod.

Kubernetes

spec:
  nodeSelector:
    disktype: [1]

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Aslow

Bssd

Clarge

Dfast

Attempts:

3 left

💡 Hint

Common Mistakes

Using a value that does not match any node label.

Confusing nodeSelector with resource requests.

The nodeSelector key is used to specify the node label that the Pod should be scheduled on. Here, disktype: ssd means the Pod will be placed on nodes labeled with disktype=ssd.

2fill in blank

medium

Complete the command to view the scheduler logs.

Kubernetes

kubectl logs -n kube-system [1]

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Akube-apiserver

Bkube-controller-manager

Cetcd

Dkube-scheduler

Attempts:

3 left

💡 Hint

Common Mistakes

Trying to get logs from the API server instead of the scheduler.

Using the wrong namespace.

The scheduler runs as a pod named kube-scheduler in the kube-system namespace. Viewing its logs helps understand Pod placement decisions.

3fill in blank

hard

Fix the error in the Pod spec to correctly use node affinity.

Kubernetes

spec:
  affinity:
    nodeAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
        nodeSelectorTerms:
        - matchExpressions:
          - key: [1]
            operator: In
            values:
            - ssd

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

Adisktype

Bdisk_type

CdiskType

Ddisk-type

Attempts:

3 left

💡 Hint

Common Mistakes

Using underscores or camelCase in label keys which do not match node labels.

Misspelling the label key.

The key must match the exact node label key. Commonly, disktype is used as a label key without underscores or camelCase.

4fill in blank

hard

Fill both blanks to create a Pod affinity rule that prefers nodes running Pods labeled 'zone=us-east'.

Kubernetes

spec:
  affinity:
    podAffinity:
      preferredDuringSchedulingIgnoredDuringExecution:
      - weight: 100
        podAffinityTerm:
          labelSelector:
            matchExpressions:
            - key: [1]
              operator: In
              values:
              - [2]

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Azone

Bus-east

Cregion

Dus-west

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up label keys and values.

Using a label value that does not exist on any node.

The affinity rule uses the label key zone and value us-east to prefer scheduling Pods on nodes already running other Pods labeled zone=us-east.

5fill in blank

hard

Fill all three blanks to define a Pod anti-affinity rule that avoids nodes running Pods with label 'app=frontend'.

Kubernetes

spec:
  affinity:
    podAntiAffinity:
      requiredDuringSchedulingIgnoredDuringExecution:
      - podAffinityTerm:
          labelSelector:
            matchExpressions:
            - key: [1]
              operator: [2]
              values:
              - [3]

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

Aapp

BIn

Cfrontend

DNotIn

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'NotIn' instead of 'In' for anti-affinity.

Using wrong label keys or values.

The anti-affinity rule uses app as the key, In as the operator to match the Pods to avoid, and frontend as the value to avoid nodes running frontend Pods.