Mock Test 3

1. Question

Create a new ServiceAccount with the name pvviewer.

Grant this ServiceAccount access to list all PersistentVolumes in the cluster by creating an appropriate ClusterRole called pvviewer-role and ClusterRoleBinding called pvviewer-role-binding.

Next, create a pod called pvviewer with the image: redis and serviceAccount: pvviewer in the default namespace.

Answer

Pods authenticate to the API Server using ServiceAccounts. If the serviceAccount name is not specified, the default service account for the namespace is used during a pod creation.

Now, create a service account pvviewer:

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k create serviceaccount pvviewer

To create a clusterrole:

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k create clusterrole pvviewer-role --resource=persistentvolumes --verb=list

To create a clusterrolebinding:

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k create clusterrolebinding pvviewer-role-binding --clusterrole=pvviewer-role --serviceaccount=default:pvviewer

Solution manifest file to create a new pod called pvviewer as follows:

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---
apiVersion: v1
kind: Pod
metadata:
  name: pvviewer
spec:
  containers:
    - image: redis
      name: pvviewer
  serviceAccountName: pvviewer

2. Question

List the InternalIP of all nodes of the cluster. Save the result to a file /root/CKA/node_ips.

Answer should be in the format: InternalIP of controlplane<space>InternalIP of node01 (in a single line)

Answer

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k get nodes -o jsonpath='{.items[*].status.addresses[?(@.type=="InternalIP")].address}' > /root/CKA/node_ips

3. Question

Create a pod called multi-pod with two containers.

Container 1: name: alpha, image: nginx

Container 2: name: beta, image: busybox, command: sleep 4800

Environment Variables:

container 1: name: alpha

Container 2: name: beta

Answer

Solution manifest file to create a multi-container pod multi-pod as follows:

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---
apiVersion: v1
kind: Pod
metadata:
  name: multi-pod
spec:
  containers:
    - name: alpha
      image: nginx
      env:
        - name: name
          value: alpha
    - name: beta
      image: busybox
      env:
        - name: name
          value: beta
      command: ["sleep", "4800"]

4. Question

Create a Pod called non-root-pod , image: redis:alpine

runAsUser: 1000

fsGroup: 2000

Answer

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---
apiVersion: v1
kind: Pod
metadata:
  name: non-root-pod
spec:
  containers:
    - name: non-root-pod
      image: redis:alpine
  securityContext:
    runAsUser: 1000
    fsGroup: 2000

Verify the user and group IDs by using below command:

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k exec -it non-root-pod -- id

5. Question

We have deployed a new pod called np-test-1 and a service called np-test-service.

Incoming connections to this service are not working. Troubleshoot and fix it.

Create NetworkPolicy, by the name ingress-to-nptest that allows incoming connections to the service over port 80.

Answer

Solution manifest file to create a network policy ingress-to-nptest as follows:

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---
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
  name: ingress-to-nptest
spec:
  podSelector:
    matchLabels:
      run: np-test-1
  policyTypes:
    - Ingress
  ingress:
    - ports:
      - protocol: TCP
        port: 80

6. Question

Taint the worker node node01 to be Unschedulable.

Once done, create a pod called dev-redis, image redis:alpine, to ensure workloads are not scheduled to this worker node.

Finally, create a new pod called prod-redis and image: redis:alpine with toleration to be scheduled on node01.

key: env_type, value: production, operator: Equal and effect: NoSchedule

Answer

To add taints on the node01 worker node:

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k taint node node01 env_type=production:NoSchedule

Now, deploy dev-redis pod and to ensure that workloads are not scheduled to this node01 worker node.

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k run dev-redis --image=redis:alpine

To view the node name of recently deployed pod:

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k get pods -o wide

Solution manifest file to deploy new pod called prod-redis with toleration to be scheduled on node01 worker node.

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---
apiVersion: v1
kind: Pod
metadata:
  name: prod-redis
spec:
  containers:
    - name: prod-redis
      image: redis:alpine
  tolerations:
    - key: env_type
      value: production
      operator: Equal
      effect: NoSchedule    

To view only prod-redis pod with less details:

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k get pods -o wide | grep prod-redis

7. Question

Create a pod called hr-pod in hr namespace belonging to the production environment and frontend tier, image: redis:alpine.

Use appropriate labels and create all the required objects if it does not exist in the system already.

Answer

Create a namespace if it doesn’t exist:

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k create namespace hr

and then create a hr-pod with given details:

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k run hr-pod --image=redis:alpine --namespace=hr --labels=environment=production,tier=frontend

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apiVersion: v1
kind: Pod
metadata:
  name: hr-pod
  labels:
    environment: production
    tier: frontend
  namespace: hr
spec:
  containers:
    - name: hr-pod
      image: redis:alpine

8. Question

A kubeconfig file called super.kubeconfig has been created under /root/CKA. There is something wrong with the configuration. Troubleshoot and fix it.

Answer

Verify host and port for kube-apiserver are correct.

Open the super.kubeconfig in vi editor.

Change the 9999 port to 6443 and run the below command to verify:

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k cluster-info --kubeconfig=/root/CKA/super.kubeconfig

9. Question

We have created a new deployment called nginx-deploy.

scale the deployment to 3 replicas. Has the replica’s increased?

Troubleshoot the issue and fix it.

Answer

Use the command k scale to increase the replica count to 3.

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k scale deploy nginx-deploy --replicas=3

The controller-manager is responsible for scaling up pods of a replicaset.

If you inspect the control plane components in the kube-system namespace, you will see that the controller-manager is not running.

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k get pods -n kube-system

The command running inside the controller-manager pod is incorrect.

After fix all the values in the file and wait for controller-manager pod to restart.

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vim /etc/kubernetes/manifests/kube-controller-manager.yaml

kube-contro1ler-manager -> kube-controller-manager

This will fix the issues in controller-manager yaml file.

At last, inspect the deployment by using below command:

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k get deploy