Default namespaces overview in Kubernetes - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the command to list all namespaces in Kubernetes.

Kubernetes

kubectl get [1]

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

Anamespaces

Bpods

Cservices

Dnodes

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pods' instead of 'namespaces' will list pods, not namespaces.

Using 'services' or 'nodes' will list other resources, not namespaces.

The command kubectl get namespaces lists all namespaces in the Kubernetes cluster.

2fill in blank

medium

Complete the command to switch to the default namespace in Kubernetes.

Kubernetes

kubectl config set-context --current --namespace=[1]

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

Adefault

Bkube-system

Cproduction

Ddev

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'kube-system' switches to the system namespace, not default.

Using custom names like 'production' or 'dev' will fail if those namespaces don't exist.

The default namespace in Kubernetes is named default. This command sets the current context to use it.

3fill in blank

hard

Fix the error in the command to describe the default namespace.

Kubernetes

kubectl describe [1] default

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

Apod

Bnode

Cservice

Dnamespace

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'pod' will try to describe a pod named 'default', which likely does not exist.

Using 'service' or 'node' will describe other resource types, not namespaces.

The resource type to describe a namespace is namespace. Using 'pod', 'service', or 'node' will describe other resources.

4fill in blank

hard

Fill both blanks to create a pod in the default namespace using kubectl.

Kubernetes

kubectl run nginx --image=nginx --restart=Never -n [1] --port=[2]

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

Adefault

B80

C443

Dkube-system

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'kube-system' will create the pod in the system namespace, not default.

Using port 443 is for HTTPS, but nginx defaults to 80.

The pod is created in the default namespace and listens on port 80, the standard HTTP port.

5fill in blank

hard

Fill all three blanks to list pods in the default namespace with wide output.

Kubernetes

kubectl get [1] -n [2] -o [3]

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

Apods

Bdefault

Cwide

Dservices

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'services' instead of 'pods' will list services, not pods.

Using other output formats like 'json' or 'yaml' will show different formats, not wide.

This command lists all pods in the default namespace with detailed information shown by the wide output option.

Practice

1. What is the purpose of namespaces in Kubernetes?

easy

A. To replace pods in the cluster

B. To increase the CPU speed of nodes

C. To organize resources into separate groups within a cluster

D. To store container images

Solution

1. Step 1: Understand what namespaces do

   Namespaces help group and isolate resources in a Kubernetes cluster.

2. Step 2: Identify the correct purpose

   They do not affect CPU speed, store images, or replace pods.

3. Final Answer:

   To organize resources into separate groups within a cluster -> Option C

4. Quick Check:

   Namespaces organize resources [OK]

Hint: Namespaces group resources logically in Kubernetes [OK]

Common Mistakes:

• Thinking namespaces speed up nodes
• Confusing namespaces with image storage
• Believing namespaces replace pods

2. Which of the following is a default namespace in Kubernetes?

easy

A. user-space

B. production

C. development

D. kube-system

Solution

1. Step 1: Recall default namespaces

   Kubernetes provides default namespaces like default, kube-system, and kube-public.

2. Step 2: Identify the correct default namespace

   kube-system is a default namespace for system components, while others are user-defined.

3. Final Answer:

   kube-system -> Option D

4. Quick Check:

   kube-system is default namespace [OK]

Hint: Remember kube-system for system pods [OK]

Common Mistakes:

• Assuming production is default
• Confusing user namespaces with defaults
• Thinking development is built-in

3. What will the command kubectl get pods -n default show?

medium

A. Pods in the default namespace

B. All pods in all namespaces

C. Pods in the kube-system namespace

D. No pods, because default namespace is empty

Solution

1. Step 1: Understand the command syntax

   kubectl get pods -n default lists pods in the namespace named default.

2. Step 2: Identify the namespace targeted

   The -n default flag limits output to the default namespace only.

3. Final Answer:

   Pods in the default namespace -> Option A

4. Quick Check:

   kubectl -n default shows default pods [OK]

Hint: -n specifies namespace for kubectl commands [OK]

Common Mistakes:

• Thinking it shows pods from all namespaces
• Confusing default with kube-system
• Assuming default namespace is always empty

4. You run kubectl get pods but get an error: error: namespace "defaultt" not found. What is the likely cause?

medium

A. Pods do not exist in any namespace

B. The namespace name is misspelled

C. kubectl is not installed

D. The cluster is down

Solution

1. Step 1: Analyze the error message

   The error says namespace "defaultt" not found, indicating a typo.

2. Step 2: Check command usage

   Likely the user typed defaultt instead of default as namespace.

3. Final Answer:

   The namespace name is misspelled -> Option B

4. Quick Check:

   Namespace typo causes not found error [OK]

Hint: Check spelling of namespace names carefully [OK]

Common Mistakes:

• Assuming pods don't exist anywhere
• Blaming kubectl installation
• Thinking cluster is down without checking

5. You want to deploy an app only visible to system components. Which default namespace should you use?

hard

A. kube-system

B. kube-public

C. default

D. custom-namespace

Solution

1. Step 1: Understand namespace roles

   kube-system holds system components and is isolated from normal user apps.

2. Step 2: Choose namespace for system visibility

   Deploying in kube-system makes the app visible only to system components.

3. Final Answer:

   kube-system -> Option A

4. Quick Check:

   System apps use kube-system namespace [OK]

Hint: Use kube-system for system-only apps [OK]

Common Mistakes:

• Using default namespace for system apps
• Choosing kube-public which is for public info
• Using a custom namespace without system access