All-Things-Docker-and-Kubernetes

Practice Test: CKAD

Some of the scenario questions here are based on Kodekloud’s CKAD course labs.

Pod Design

Note

CKAD and CKA can have similar scenario questions. It is recommended to go through the CKA practice tests.

Shortcuts

First run the two commands below for shortcuts.

export do="--dry-run=client -o yaml" 
export now="--force --grace-period=0" 

Questions

Upgrade the application by setting the image on the deployment to kodekloud/webapp-color:v2. Do not delete and re-create the deployment. Only set the new image name for the existing deployment.
```
 controlplane ~ ✦ ➜ k get deployments.apps 
 NAME READY UP-TO-DATE AVAILABLE AGE
 frontend 4/4 4 4 6m46s 
```
Answer
```bash controlplane ~ ✦ ✖ k set image deploy frontend simple-webapp=kodekloud/webapp-color:v2 deployment.apps/frontend image updated ``` ```bash controlplane ~ ➜ k get deployments.apps NAME READY UP-TO-DATE AVAILABLE AGE frontend 5/4 4 3 5m18s ```
Change the deployment strategy to Recreate.
```
 controlplane ~ ✦ ➜ k get deployments.apps 
 NAME READY UP-TO-DATE AVAILABLE AGE
 frontend 4/4 4 4 6m46s 
```
Answer
```bash controlplane ~ ✦2 ➜ k get deployments.apps NAME READY UP-TO-DATE AVAILABLE AGE frontend 4/4 4 4 8m14s controlplane ~ ✦2 ➜ k get deployments.apps frontend -o yaml > frontend.yml controlplane ~ ✦2 ➜ k delete -f frontend.yml deployment.apps "frontend" deleted controlplane ~ ✦2 ➜ k get deployments.apps No resources found in default namespace. ``` ```yaml ## frontend.yml --- apiVersion: apps/v1 kind: Deployment metadata: name: frontend namespace: default spec: replicas: 4 selector: matchLabels: name: webapp strategy: type: Recreate template: metadata: labels: name: webapp spec: containers: - image: kodekloud/webapp-color:v2 name: simple-webapp ports: - containerPort: 8080 protocol: TCP ``` ```bash controlplane ~ ✦2 ➜ k apply -f frontend.yml deployment.apps/frontend created controlplane ~ ✦2 ➜ k get deployments.apps NAME READY UP-TO-DATE AVAILABLE AGE frontend 4/4 4 4 6s ```
A pod definition file named throw-dice-pod.yaml is given. The image throw-dice randomly returns a value between 1 and 6. 6 is considered success and all others are failure. Try deploying the POD and view the POD logs for the generated number. File is located at /root/throw-dice-pod.yaml
```
 controlplane ~ ➜ cat throw-dice-pod.yaml 
 apiVersion: v1
 kind: Pod
 metadata:
 name: throw-dice-pod
 spec:
 containers:
 - image: kodekloud/throw-dice
 name: throw-dice
 restartPolicy: Never 
```
Next, create a Job using this POD definition file or from the imperative command and look at how many attempts does it take to get a ‘6’.
- Job Name: throw-dice-job
- Image Name: kodekloud/throw-dice
Then update the job definition to run as many times as required to get 3 successful 6’s

Answer
```bash controlplane ~ ➜ k apply -f throw-dice-pod.yaml pod/throw-dice-pod created controlplane ~ ➜ k get po NAME READY STATUS RESTARTS AGE throw-dice-pod 0/1 ContainerCreating 0 3s controlplane ~ ➜ k get po NAME READY STATUS RESTARTS AGE throw-dice-pod 0/1 Error 0 4s controlplane ~ ➜ k logs throw-dice-pod 5 ``` Create the job. ```bash controlplane ~ ➜ k create job throw-dice-job --image kodekloud/throw-dice $do apiVersion: batch/v1 kind: Job metadata: creationTimestamp: null name: throw-dice-job spec: template: metadata: creationTimestamp: null spec: containers: - image: kodekloud/throw-dice name: throw-dice-job resources: {} restartPolicy: Never status: {} controlplane ~ ➜ k create job throw-dice-job --image kodekloud/throw-dice $do > job.yml ``` ```bash ## job.yml apiVersion: batch/v1 kind: Job metadata: creationTimestamp: null name: throw-dice-job spec: backoffLimit: 15 template: metadata: creationTimestamp: null spec: containers: - image: kodekloud/throw-dice name: throw-dice-job resources: {} restartPolicy: Never status: {} ``` ```bash controlplane ~ ➜ k apply -f job.yml job.batch/throw-dice-job created controlplane ~ ➜ k get job NAME COMPLETIONS DURATION AGE throw-dice-job 0/1 4s 4s ``` Update the job definition to run as many times as required to get 3 successful 6's ```yaml apiVersion: batch/v1 kind: Job metadata: name: throw-dice-job spec: completions: 3 backoffLimit: 25 # This is so the job does not quit before it succeeds. template: spec: containers: - name: throw-dice image: kodekloud/throw-dice restartPolicy: Never ```
Using the same YAML file from the previous question, speed it up by running upto 3 jobs in parallel.
```
 controlplane ~ ✦2 ➜ k get job
 NAME COMPLETIONS DURATION AGE
 throw-dice-job 3/3 15s 40s 
```
Answer
```bash controlplane ~ ✦2 ➜ k delete job throw-dice-job job.batch "throw-dice-job" deleted controlplane ~ ✦2 ➜ k get job No resources found in default namespace. ``` ```yaml ## job.yml apiVersion: batch/v1 kind: Job metadata: name: throw-dice-job spec: parallelism: 3 completions: 3 backoffLimit: 25 # This is so the job does not quit before it succeeds. template: spec: containers: - name: throw-dice image: kodekloud/throw-dice restartPolicy: Never ``` ```bash controlplane ~ ✦2 ➜ k apply -f job.yml job.batch/throw-dice-job created ```
Using the same YAML file from the previous question, schedule that job to run at 21:30 hours every day.

Answer
```yaml ## cronjob.yml apiVersion: batch/v1 kind: CronJob metadata: name: throw-dice-cron-job spec: schedule: "30 21 * * *" jobTemplate: spec: completions: 3 parallelism: 3 backoffLimit: 25 # This is so the job does not quit before it succeeds. template: spec: containers: - name: throw-dice image: kodekloud/throw-dice restartPolicy: Never ``` ```bash controlplane ~ ✦5 ➜ k apply -f cronjob.yml cronjob.batch/throw-dice-cron-job created controlplane ~ ✦5 ➜ k get cronjobs.batch NAME SCHEDULE SUSPEND ACTIVE LAST SCHEDULE AGE throw-dice-cron-job 30 21 * * * False 0 8s ``` </details>

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