Creating Pods with kubectl in Kubernetes - Practice Exercises

Challenge - 5 Problems

💻 Command Output

intermediate

What is the output of creating a pod with a missing image field?

You run the command kubectl run mypod --restart=Never --image= with an empty image value. What will kubectl output?

Kubernetes

kubectl run mypod --restart=Never --image=

A error: required flag(s) "image" not set

B pod/mypod created

C Warning: image field is empty, pod created but will fail to start

D command not found

💡 Hint

The image field is mandatory when creating a pod with kubectl run.

The --image flag is required to specify the container image. Leaving it empty causes kubectl to error out.

❓ Configuration

intermediate

Which YAML snippet correctly defines a pod with one container named 'web' running nginx?

Select the correct YAML configuration for a pod named 'web-pod' with a single container named 'web' using the nginx image.

A

apiVersion: v1
kind: Pod
metadata:
  name: web-pod
spec:
  containers:
  - web
  - image: nginx

B

apiVersion: v1
kind: Pod
metadata:
  name: web-pod
spec:
  containers:
    name: web
    image: nginx

C

apiVersion: v1
kind: Pod
metadata:
  name: web-pod
spec:
  containers:
  - name: web
    image: nginx

D

apiVersion: v1
kind: Pod
metadata:
  name: web-pod
spec:
  container:
  - name: web
    image: nginx

💡 Hint

The containers field must be a list with each container having a name and image.

Option C correctly uses the containers list with a container object having name and image fields.

🔀 Workflow

advanced

What is the correct sequence to create a pod from a YAML file and verify it is running?

Arrange the steps in the correct order to create a pod from a YAML file named pod.yaml and check its status.

A 1,2,4,3

B 1,2,3,4

C 1,3,2,4

D 2,1,3,4

💡 Hint

First create, then list, then inspect, then optionally delete.

The correct workflow is to apply the YAML, check pods, describe the pod for details, and delete if needed.

❓ Troubleshoot

advanced

What error will occur if you try to create a pod with an invalid apiVersion?

You use this YAML snippet to create a pod but the apiVersion is set to 'v2': apiVersion: v2 kind: Pod metadata: name: test-pod spec: containers: - name: test image: busybox command: ['sleep', '3600'] What error will kubectl show?

A error: unable to recognize "pod.yaml": no matches for kind "Pod" in version "v2"

B pod/test-pod created

C error: unknown flag: --apiVersion

D Warning: apiVersion v2 deprecated, pod created with warnings

💡 Hint

apiVersion must be a valid Kubernetes API version.

Using an invalid apiVersion causes kubectl to fail recognizing the resource kind.

✅ Best Practice

expert

Which kubectl command correctly creates a pod named 'fast-pod' with the image 'nginx' and disables restart policy?

Choose the command that creates a pod named 'fast-pod' using the nginx image and ensures the pod will not restart automatically.

A kubectl create pod fast-pod --image=nginx --restart=Always

B kubectl create pod fast-pod --image=nginx --restart=Never

C kubectl run fast-pod --image=nginx --restart=Always

D kubectl run fast-pod --image=nginx --restart=Never

💡 Hint

The restart policy 'Never' disables automatic pod restarts.

The kubectl run command with --restart=Never creates a pod that does not restart automatically.

Practice

1. What does the command kubectl run mypod --image=nginx --restart=Never do?

easy

A. Creates a single Pod named 'mypod' running the nginx image

B. Creates a Deployment named 'mypod' running the nginx image

C. Deletes the Pod named 'mypod' if it exists

D. Updates the nginx image in all Pods

Solution

1. Step 1: Understand the kubectl run command

   The command kubectl run creates a resource to run containers. By default, it creates a Deployment unless specified otherwise.

2. Step 2: Effect of --restart=Never

   Adding --restart=Never tells Kubernetes to create a Pod directly, not a Deployment.

3. Final Answer:

   Creates a single Pod named 'mypod' running the nginx image -> Option A

4. Quick Check:

   kubectl run + --restart=Never = Pod creation [OK]

Hint: Use --restart=Never to create a Pod, not a Deployment [OK]

Common Mistakes:

• Assuming kubectl run always creates a Deployment
• Forgetting --restart=Never creates a Pod
• Confusing Pod creation with deletion

2. Which of the following is the correct syntax to create a Pod named 'testpod' using the busybox image with kubectl?

easy

A. kubectl run testpod --image=busybox --restart=Never

B. kubectl create pod testpod --image=busybox

C. kubectl deploy testpod --image=busybox

D. kubectl pod create testpod --image=busybox

Solution

1. Step 1: Identify the correct kubectl command for Pod creation

   The kubectl run command with --restart=Never creates a Pod directly.

2. Step 2: Check each option's syntax

   kubectl create pod testpod --image=busybox uses kubectl create pod which is invalid. kubectl deploy testpod --image=busybox uses kubectl deploy which is not a kubectl command. kubectl pod create testpod --image=busybox uses kubectl pod create which is invalid. Only kubectl run testpod --image=busybox --restart=Never is correct syntax.

3. Final Answer:

   kubectl run testpod --image=busybox --restart=Never -> Option A

4. Quick Check:

   kubectl run + --restart=Never = Pod creation [OK]

Hint: Use 'kubectl run name --image=img --restart=Never' for Pod creation [OK]

Common Mistakes:

• Using 'kubectl create pod' which is invalid
• Confusing 'deploy' with 'run'
• Omitting --restart=Never to create a Pod

3. What will be the output of the command kubectl get pods immediately after running kubectl run demo --image=nginx --restart=Never?

medium

A. A Deployment named 'demo' will be listed instead of a Pod

B. No Pods will be listed because the command creates a Deployment

C. A Pod named 'demo' will be listed with STATUS 'Running' or 'ContainerCreating'

D. An error message saying 'unknown command run'

Solution

1. Step 1: Understand the effect of the run command with --restart=Never

   This command creates a Pod named 'demo' running the nginx image.

2. Step 2: Check what kubectl get pods shows

   It lists all Pods. Since the Pod was just created, it will appear with status 'Running' or 'ContainerCreating'.

3. Final Answer:

   A Pod named 'demo' will be listed with STATUS 'Running' or 'ContainerCreating' -> Option C

4. Quick Check:

   kubectl run + --restart=Never creates Pod listed by get pods [OK]

Hint: Pods created with --restart=Never appear in 'kubectl get pods' [OK]

Common Mistakes:

• Expecting a Deployment to appear in pod list
• Thinking no pods appear immediately
• Confusing command output with error

4. You run kubectl run app --image=nginx but no Pod named 'app' appears when you run kubectl get pods. What is the likely cause?

medium

A. The image name 'nginx' is invalid, so Pod creation failed

B. The command created a Deployment, not a Pod named 'app', so no Pod named 'app' appears

C. You need to add --restart=Always to create a Pod

D. The Pod was created but immediately deleted by Kubernetes

Solution

1. Step 1: Understand default behavior of kubectl run without --restart=Never

   By default, kubectl run creates a Deployment, not a Pod.

2. Step 2: Check why 'kubectl get pods' shows no Pod named 'app'

   Since a Deployment manages Pods, the Pod(s) are named like 'app-[hash]', not 'app'. The command kubectl get deployments would show the Deployment.

3. Final Answer:

   The command created a Deployment, not a Pod named 'app', so no Pod named 'app' appears -> Option B

4. Quick Check:

   kubectl run without --restart=Never creates Deployment [OK]

Hint: Add --restart=Never to create a Pod, else Deployment is created [OK]

Common Mistakes:

• Assuming kubectl run always creates a Pod
• Thinking image name caused failure without error
• Confusing --restart=Always with Pod creation

5. You want to create a Pod named 'webserver' running the nginx image that does NOT restart automatically if it crashes. Which command should you use?

hard

A. kubectl run webserver --image=nginx

B. kubectl run webserver --image=nginx --restart=Always

C. kubectl create pod webserver --image=nginx --restart=Never

D. kubectl run webserver --image=nginx --restart=Never

Solution

1. Step 1: Understand restart policies in kubectl run

   Using --restart=Never creates a Pod with restart policy 'Never', so it won't restart automatically.

2. Step 2: Evaluate each option

   kubectl run webserver --image=nginx --restart=Never correctly uses --restart=Never. kubectl run webserver --image=nginx --restart=Always uses --restart=Always which creates a Deployment that restarts Pods. kubectl create pod webserver --image=nginx --restart=Never uses invalid syntax. kubectl run webserver --image=nginx creates a Deployment by default.

3. Final Answer:

   kubectl run webserver --image=nginx --restart=Never -> Option D

4. Quick Check:

   --restart=Never means Pod won't auto-restart [OK]

Hint: Use --restart=Never to prevent Pod auto-restart on failure [OK]

Common Mistakes:

• Using default restart which creates Deployment
• Confusing --restart=Always with no restart
• Trying invalid commands like kubectl create pod