Scaling Deployments in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to scale a deployment named webapp to 3 replicas.

Kubernetes

kubectl scale deployment webapp --replicas=[1]

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

A5

B0

C1

D3

Attempts:

3 left

💡 Hint

Common Mistakes

Using 0 replicas will stop all pods.

Using a number too high may overload your cluster.

The --replicas flag sets the number of desired pods. Here, 3 replicas means 3 pods will run.

2fill in blank

medium

Complete the command to check the current number of replicas for deployment api-server.

Kubernetes

kubectl get deployment api-server -o [1]

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Ajsonpath='{.status.replicas}'

Bwide

Cyaml

Djson

Attempts:

3 left

💡 Hint

Common Mistakes

Using wide shows more info but not just replicas.

Using yaml or json shows full details.

The jsonpath output format lets you extract specific fields. Here, it shows the number of replicas.

3fill in blank

hard

Fix the error in this command to scale deployment frontend to 4 replicas.

Kubernetes

kubectl scale deployment frontend --replicas [1]

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

Ato 4

B=4

C4

D-4

Attempts:

3 left

💡 Hint

Common Mistakes

Using '=4' sets an invalid replicas value '=4'.

Adding words like 'to' is invalid.

The correct syntax uses --replicas=4 or --replicas 4. Here, the space without '=' is valid, so just '4' is correct.

4fill in blank

hard

Fill both blanks to create a YAML snippet that sets replicas to 5 for a deployment.

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: myapp
spec:
  replicas: [1]
  selector:
    matchLabels:
      app: [2]

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

A5

Bmyapp

C3

Dwebapp

Attempts:

3 left

💡 Hint

Common Mistakes

Using a wrong number for replicas.

Mismatching the app label causes selector issues.

The replicas field sets how many pods run. The app label must match the deployment name or selector.

5fill in blank

hard

Fill all three blanks to create a command that scales deployment backend to 6 replicas and outputs the updated replicas count.

Kubernetes

kubectl scale deployment [1] --replicas=[2] && kubectl get deployment [3] -o jsonpath='{.status.replicas}'

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

Abackend

B6

Dfrontend

Attempts:

3 left

💡 Hint

Common Mistakes

Using different deployment names causes errors.

Mismatching replicas number causes confusion.

The deployment name must be consistent in both commands. The replicas number is 6 as requested.

Practice

1. What does scaling a Kubernetes deployment do?

easy

A. Changes the number of running copies (pods) of the app

B. Updates the app's source code automatically

C. Deletes the deployment from the cluster

D. Changes the app's network settings

Solution

1. Step 1: Understand the purpose of scaling

   Scaling means adjusting how many copies of an app run to handle load or save resources.

2. Step 2: Identify what scaling affects

   Scaling changes the number of pods, which are running instances of the app.

3. Final Answer:

   Changes the number of running copies (pods) of the app -> Option A

4. Quick Check:

   Scaling = Change pod count [OK]

Hint: Scaling means changing pod count, not code or network [OK]

Common Mistakes:

• Thinking scaling updates app code
• Confusing scaling with deleting deployments
• Assuming scaling changes network settings

2. Which is the correct command to scale a deployment named webapp to 5 replicas?

easy

A. kubectl scale pods webapp --count=5

B. kubectl update deployment webapp --replicas 5

C. kubectl set replicas webapp 5

D. kubectl scale deployment webapp --replicas=5

Solution

1. Step 1: Recall the correct kubectl scale syntax

   The command to scale is kubectl scale deployment [name] --replicas=[number].

2. Step 2: Match the command to the options

   kubectl scale deployment webapp --replicas=5 matches the correct syntax exactly for deployment webapp to 5 replicas.

3. Final Answer:

   kubectl scale deployment webapp --replicas=5 -> Option D

4. Quick Check:

   Correct scale syntax = kubectl scale deployment webapp --replicas=5 [OK]

Hint: Use 'kubectl scale deployment NAME --replicas=N' exactly [OK]

Common Mistakes:

• Using 'pods' instead of 'deployment'
• Wrong flag like --count instead of --replicas
• Using 'kubectl update' which is invalid for scaling

3. Given this command:
kubectl scale deployment frontend --replicas=3
What will be the number of pods running for the frontend deployment after execution?

medium

A. 0

B. 1

C. 3

D. Depends on cluster resources

Solution

1. Step 1: Understand the scale command effect

   The command sets the number of replicas (pods) to 3 explicitly.

2. Step 2: Determine the pod count after scaling

   After running, Kubernetes will ensure exactly 3 pods for the frontend deployment.

3. Final Answer:

   3 -> Option C

4. Quick Check:

   --replicas=3 means 3 pods [OK]

Hint: Replicas number = pods count after scaling [OK]

Common Mistakes:

• Assuming pods stay at 1 by default
• Thinking scaling depends on cluster resources
• Confusing replicas with CPU or memory

4. You run kubectl scale deployment backend --replicas=two but get an error. What is the problem?

medium

A. The deployment name 'backend' is invalid

B. The replicas value must be a number, not a word

C. The command should use 'kubectl update' instead

D. You need to add --force flag to scale

Solution

1. Step 1: Check the replicas argument type

   The replicas flag requires a numeric value, not a word like 'two'.

2. Step 2: Identify the cause of the error

   Using 'two' causes a syntax error because Kubernetes expects an integer.

3. Final Answer:

   The replicas value must be a number, not a word -> Option B

4. Quick Check:

   Replicas must be numeric [OK]

Hint: Replicas must be a number, not text [OK]

Common Mistakes:

• Using words instead of numbers for replicas
• Thinking deployment name is invalid without checking
• Trying to use 'kubectl update' for scaling

5. You want to scale a deployment named api-server from 2 to 10 replicas but only 6 nodes are available in your cluster. What will happen after running kubectl scale deployment api-server --replicas=10?

hard

A. Only 6 pods will run because of node limits, others stay pending

B. The deployment will scale to 2 pods automatically

C. The command will fail with an error about node count

D. Kubernetes will create 10 pods regardless of node count

Solution

1. Step 1: Understand Kubernetes scheduling with limited nodes

   Kubernetes tries to run all requested pods but can only schedule as many as fit on available nodes.

2. Step 2: Predict pod status with 10 replicas but 6 nodes

   Only 6 pods will be scheduled and running; the other 4 pods remain pending until resources free up.

3. Final Answer:

   Only 6 pods will run because of node limits, others stay pending -> Option A

4. Quick Check:

   Pods limited by nodes = pending pods [OK]

Hint: Pods > nodes means some pods stay pending [OK]

Common Mistakes:

• Assuming all pods run regardless of nodes
• Expecting command to fail on node shortage
• Thinking deployment scales down automatically