Udemy Mock Exam - 1

1. Deploy a pod named nginx-pod using the nginx:alpine image.

Deploy a pod named nginx-pod using the nginx:alpine image.

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- Name: nginx-pod
- Image: nginx:alpine

 

 

controlplane ~ ➜  k run nginx-pod --image=nginx:alpine --dry-run=client -o yaml > pod.yaml

controlplane ~ ➜  ls
pod.yaml  sample.yaml

controlplane ~ ➜  k apply -f pod.yaml 
pod/nginx-pod created

 

 

---

2. Deploy a messaging pod using the redis:alpine image with the labels set to tier=msg.

Deploy a messaging pod using the redis:alpine image with the labels set to tier=msg.


- Pod Name: messaging

- Image: redis:alpine

- Labels: tier=msg

 

controlplane ~ ➜  k run --help |grep labels
  # Start a hazelcast pod and set labels "app=hazelcast" and "env=prod" in the container
  
  kubectl run hazelcast --image=hazelcast/hazelcast --labels="app=hazelcast,env=prod"
    
    -l, --labels='':
        Comma separated labels to apply to the pod. Will override previous values.

 

controlplane ~ ➜  k run messaging --image=redis:alpine --labels="tier=msg" --dry-run=client -o yaml > message.yaml

controlplane ~ ➜  cat message.yaml 
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    tier: msg
  name: messaging
spec:
  containers:
  - image: redis:alpine
    name: messaging
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}



controlplane ~ ➜  k apply -f message.yaml 
pod/messaging created

 

 

 

---

3. Create a namespace named apx-x9984574.

Create a namespace named apx-x9984574.


- Namespace: apx-x9984574

 

controlplane ~ ✖ k create --help |grep namespace
  namespace             Create a namespace with the specified name

controlplane ~ ➜  k create namespace apx-x9984574
namespace/apx-x9984574 created


controlplane ~ ➜  k get ns
NAME              STATUS   AGE
apx-x9984574      Active   18s
default           Active   124m
finance           Active   12m
kube-flannel      Active   124m
kube-node-lease   Active   124m
kube-public       Active   124m
kube-system       Active   124m

 

 

---

4. Get the list of nodes in JSON format and store it in a file at 

     /opt/outputs/nodes-z3444kd9.json. 

Get the list of nodes in JSON format and store it in a file at 
/opt/outputs/nodes-z3444kd9.json. 

- Task completed

 

controlplane ~ ➜  k get nodes  -o json > /opt/outputs/node-z3444kd9.json

 

 

Examples using kubectl and JSONPath expressions:

kubectl get pods -o json
kubectl get pods -o=jsonpath='{@}'
kubectl get pods -o=jsonpath='{.items[0]}'
kubectl get pods -o=jsonpath='{.items[0].metadata.name}'
kubectl get pods -o=jsonpath="{.items[*]['metadata.name', 'status.capacity']}"
kubectl get pods -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.startTime}{"\n"}{end}'
kubectl get pods -o=jsonpath='{.items[0].metadata.labels.kubernetes\.io/hostname}'

https://kubernetes.io/docs/reference/kubectl/jsonpath/

 

---

5. Create a service messaging-service to expose

    the messaging application within the cluster on port 6379.

Create a service messaging-service to expose 
the messaging application within the cluster on port 6379.

Use imperative commands.

- Service: messaging-service
- Port: 6379
- Type: ClusterIp
- Use the right labels

 

controlplane ~ ✖ k get pods
NAME        READY   STATUS             RESTARTS       AGE
deploy      0/1     CrashLoopBackOff   8 (5m6s ago)   21m
messaging   1/1     Running            0              10m
nginx-pod   1/1     Running            0              16m

controlplane ~ ➜  k get svc
NAME         TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
kubernetes   ClusterIP   10.96.0.1    <none>        443/TCP   132m

 

controlplane ~ ➜  k expose pod messaging --port 6379 --name messaging-service
service/messaging-service exposed

controlplane ~ ➜  k get svc
NAME                TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
kubernetes          ClusterIP   10.96.0.1       <none>        443/TCP    137m
messaging-service   ClusterIP   10.110.44.209   <none>        6379/TCP   5s

controlplane ~ ➜  k describe svc messaging-service |grep -i end
Endpoints:         10.244.0.6:6379

controlplane ~ ➜  k describe svc messaging-service |grep -i type
Type:              ClusterIP

 

 

---

6. Create a deployment named hr-web-app using the image kodekloud/webapp-color with 2 replicas.

Create a deployment named hr-web-app using the image kodekloud/webapp-color with 2 replicas.


- Name: hr-web-app
- Image: kodekloud/webapp-color
- Replicas: 2

 

controlplane ~ ➜  k create deployment hr-web-app --image kodekloud/we
bapp-color --replicas 2
deployment.apps/hr-web-app created

controlplane ~ ➜  k get deployment
NAME         READY   UP-TO-DATE   AVAILABLE   AGE
hr-web-app   2/2     2            2           7s

 

 

 

---

7. Create a static pod named static-busybox on the controlplane node

    that uses the busybox image and the command sleep 1000.

Create a static pod named static-busybox on the controlplane node 
that uses the busybox image and the command sleep 1000.


- Name: static-busybox
- Image: busybox

 

controlplane ~ ➜  k run static-busybox --image=busybox --dry-run=client -o yaml --command -- sleep 1000 > static.yaml


controlplane ~ ✖ k apply -f static.yaml 
pod/static-busybox created


controlplane ~ ➜  k get pods -o wide
NAME                          READY   STATUS    RESTARTS   AGE   IP           NODE           NOMINATED NODE   READINESS GATES
hr-web-app-5d6b77db78-f8slm   1/1     Running   0          10m   10.244.0.7   controlplane   <none>           <none>
hr-web-app-5d6b77db78-v4rjn   1/1     Running   0          10m   10.244.0.6   controlplane   <none>           <none>
messaging                     1/1     Running   0          24m   10.244.0.5   controlplane   <none>           <none>
nginx-pod                     1/1     Running   0          27m   10.244.0.4   controlplane   <none>           <none>
static-busybox                1/1     Running   0          15s   10.244.0.8   controlplane   <none>           <none>

Q. 7

 

Task

Create a static pod named static-busybox on the controlplane node that uses the busybox image and the command sleep 1000.

 

Solution

Create a pod definition file in the manifests directory. For that use command kubectl run --restart=Never --image=busybox static-busybox --dry-run=client -oyaml --command -- sleep 1000 > /etc/kubernetes/manifests/static-busybox.yaml

 

Details

Name: static-busybox

Image: busybox

 

controlplane ~ ➜  k run static-busybox --image=busybox --dry-run=client -o yaml --command -- sleep 1000 > static-busybox.yaml

controlplane ~ ➜  k get pods
NAME                          READY   STATUS    RESTARTS   AGE
hr-web-app-5d6b77db78-qsm6k   1/1     Running   0          23m
hr-web-app-5d6b77db78-v5hkq   1/1     Running   0          23m
messaging                     1/1     Running   0          25m
nginx-pod                     1/1     Running   0          25m
static-busybox-controlplane   1/1     Running   0          18s

 

 

---

8. Create a POD in the finance namespace named temp-bus with the image redis:alpine.

Create a POD in the finance namespace named temp-bus with the image redis:alpine.


- Name: temp-bus
- Image Name: redis:alpine

 

 

controlplane ~ ✖ k run temp-bus --image=redis:alpine -n finance
pod/temp-bus created

 

 

 

---

9. A new application orange is deployed. There is something wrong with it. Identify and fix the issue.

A new application orange is deployed. There is something wrong with it. 
Identify and fix the issue.


- Issue fixed

 

 

controlplane ~ ➜  k get pods
NAME                          READY   STATUS                  RESTARTS      AGE
hr-web-app-5d6b77db78-f8slm   1/1     Running                 0             19m
hr-web-app-5d6b77db78-v4rjn   1/1     Running                 0             19m
messaging                     1/1     Running                 0             34m
nginx-pod                     1/1     Running                 0             36m
orange                        0/1     Init:CrashLoopBackOff   4 (55s ago)   2m25s
static-busybox                1/1     Running                 0             9m49s


controlplane ~ ✖ k describe pod orange
...
..
.

Events:
  Type     Reason     Age                     From               Message
  ----     ------     ----                    ----               -------
  Normal   Scheduled  9m27s                   default-scheduler  Successfully assigned default/orange to controlplane
  Normal   Pulled     9m26s                   kubelet            Successfully pulled image "busybox" in 180ms (180ms including waiting). Image size: 2160406 bytes.
  Normal   Pulled     9m25s                   kubelet            Successfully pulled image "busybox" in 187ms (187ms including waiting). Image size: 2160406 bytes.
  Normal   Pulled     9m10s                   kubelet            Successfully pulled image "busybox" in 254ms (254ms including waiting). Image size: 2160406 bytes.
  Normal   Pulled     8m47s                   kubelet            Successfully pulled image "busybox" in 157ms (157ms including waiting). Image size: 2160406 bytes.
  Normal   Created    8m46s (x4 over 9m26s)   kubelet            Created container init-myservice
  Normal   Started    8m46s (x4 over 9m25s)   kubelet            Started container init-myservice
  Normal   Pulling    7m58s (x5 over 9m26s)   kubelet            Pulling image "busybox"
  Normal   Pulled     7m58s                   kubelet            Successfully pulled image "busybox" in 151ms (151ms including waiting). Image size: 2160406 bytes.
  Warning  BackOff    4m24s (x24 over 9m24s)  kubelet            Back-off restarting failed container init-myservice in pod orange_default(3e84f7af-8b5e-4049-b1a3-634f8e5d5b60)
  
  
  controlplane ~ ✖ k get pod orange -o yaml > orange.yaml
  
  
  controlplane ~ ➜  k logs orange 
Defaulted container "orange-container" out of: orange-container, init-myservice (init)
Error from server (BadRequest): container "orange-container" in pod "orange" is waiting to start: PodInitializing

controlplane ~ ✖ k logs orange init-myservice
sh: sleeeep: not found

 

controlplane ~ ➜  vim orange.yaml 
  1 apiVersion: v1
  2 kind: Pod
  3 metadata:
  4   creationTimestamp: "2024-07-31T14:01:42Z"
  5   name: orange
  6   namespace: default
  7   resourceVersion: "6369"
  8   uid: 3e84f7af-8b5e-4049-b1a3-634f8e5d5b60
  9 spec:
 10   containers:
 11   - command:
 12     - sh
 13     - -c
 14     - echo The app is running! && sleep 3600
 15     image: busybox:1.28
 16     imagePullPolicy: IfNotPresent
 17     name: orange-container
 18     resources: {}
 19     terminationMessagePath: /dev/termination-log
 20     terminationMessagePolicy: File
 21     volumeMounts:
 22     - mountPath: /var/run/secrets/kubernetes.io/serviceaccount
 23       name: kube-api-access-wgmhs
 24       readOnly: true
 25   dnsPolicy: ClusterFirst
 26   enableServiceLinks: true
 27   initContainers:
 28   - command:
 29     - sh
 30     - -c
 31     - sleeeeep 2; ->  - sleep 2;

 

controlplane ~ ✖ k delete pod orange
pod "orange" deleted

controlplane ~ ➜  k apply -f orange.yaml 
pod/orange created

controlplane ~ ➜  k get pod
NAME                          READY   STATUS     RESTARTS       AGE
hr-web-app-5d6b77db78-f8slm   1/1     Running    0              32m
hr-web-app-5d6b77db78-v4rjn   1/1     Running    0              32m
messaging                     1/1     Running    0              47m
nginx-pod                     1/1     Running    0              49m
orange                        0/1     Init:0/1   0              3s
static-busybox                1/1     Running    1 (6m1s ago)   22m

controlplane ~ ➜  k get pod
NAME                          READY   STATUS    RESTARTS       AGE
hr-web-app-5d6b77db78-f8slm   1/1     Running   0              32m
hr-web-app-5d6b77db78-v4rjn   1/1     Running   0              32m
messaging                     1/1     Running   0              47m
nginx-pod                     1/1     Running   0              49m
orange                        1/1     Running   0              6s
static-busybox                1/1     Running   1 (6m4s ago)   22m

 

Q. 9

 

Task

A new application orange is deployed. There is something wrong with it. Identify and fix the issue.

 

Solution

To know more details of orange pod:

kubectl describe po orange

and look under the initContainers section. There is an issue with the given command.

 Command:
      sh
      -c
      sleeeep 2;

 

In the above, we need to correct the sleeeep command.

To update the pod with an easiest way by running command:

kubectl edit po orange

It's not possible to update the changes in the running pod so after saving the changes. It will create a temporary file in the default location /tmp/.

Use that manifest file and replace with the existing pod:

kubectl replace -f /tmp/kubectl-edit-xxxx.yaml --force

Above command will delete the existing pod and will recreate the new pod with latest changes.

 

 

Details

 

- Issue fixed

---

10. Expose the hr-web-app as service hr-web-app-service application 
      on port 30082 on the nodes on the cluster.

Expose the hr-web-app as service hr-web-app-service application 
on port 30082 on the nodes on the cluster.


The web application listens on port 8080.

- Name: hr-web-app-service
- Type: NodePort
- Endpoints: 2
- Port: 8080
- NodePort: 30082

 

controlplane ~ ➜  k get svc
NAME                 TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)          AGE
hr-web-app-service   NodePort    10.101.138.173   <none>        8080:30260/TCP   21s
kubernetes           ClusterIP   10.96.0.1        <none>        443/TCP          94m
messaging-service    ClusterIP   10.96.213.11     <none>        6379/TCP         46m

 

 

controlplane ~ ➜  k edit svc hr-web-app-service 
service/hr-web-app-service edited

 17   spec:
 18     clusterIP: 10.101.138.173
 19     clusterIPs:
 20     - 10.101.138.173
 21     externalTrafficPolicy: Cluster
 22     internalTrafficPolicy: Cluster
 23     ipFamilies:
 24     - IPv4
 25     ipFamilyPolicy: SingleStack
 26     ports:
 27     - nodePort: 300082  ## <<-----fixed
 28       port: 8080
 29       protocol: TCP
 30       targetPort: 8080
 31     selector:
 32       app: hr-web-app
 33     sessionAffinity: None
 34     type: NodePort

---

 

 

11. Use JSON PATH query to retrieve the osImages of all the nodes and store it in a file /opt/outputs/nodes_os_x43kj56.txt.

Use JSON PATH query to retrieve the osImages of all the nodes and store it in a file /opt/outputs/nodes_os_x43kj56.txt.


The osImages are under the nodeInfo section under status of each node.

Task Completed

 

 

 

Examples using kubectl and JSONPath expressions:

kubectl get pods -o json
kubectl get pods -o=jsonpath='{@}'
kubectl get pods -o=jsonpath='{.items[0]}'
kubectl get pods -o=jsonpath='{.items[0].metadata.name}'
kubectl get pods -o=jsonpath="{.items[*]['metadata.name', 'status.capacity']}"
kubectl get pods -o=jsonpath='{range .items[*]}{.metadata.name}{"\t"}{.status.startTime}{"\n"}{end}'
kubectl get pods -o=jsonpath='{.items[0].metadata.labels.kubernetes\.io/hostname}'

https://kubernetes.io/docs/reference/kubectl/jsonpath/

 

 

controlplane ~ ➜  k get nodes -o jsonpath='{.items[*].status.nodeInfo.osImages}' > /opt/outputs/nodes_os_x43kj56.txt

 

Q. 11

 

Task

Use JSON PATH query to retrieve the osImages of all the nodes and store it in a file /opt/outputs/nodes_os_x43kj56.txt.

The osImages are under the nodeInfo section under status of each node.

 

Solution

Run the command: kubectl get nodes -o jsonpath='{.items[*].status.nodeInfo.osImage}' > /opt/outputs/nodes_os_x43kj56.txt

 

Details

Task Completed

---

 

 

12. Create a Persistent Volume with the given specification: -

Create a Persistent Volume with the given specification: -

Volume name: pv-analytics

Storage: 100Mi

Access mode: ReadWriteMany

Host path: /pv/data-analytics


Is the volume name set?

Is the storage capacity set?

Is the accessMode set?

Is the hostPath set?

 

 

https://kubernetes.io/docs/concepts/storage/persistent-volumes/#persistent-volumes

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv0003
spec:
  capacity:
    storage: 5Gi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteOnce
  persistentVolumeReclaimPolicy: Recycle
  storageClassName: slow
  mountOptions:
    - hard
    - nfsvers=4.1
  nfs:
    path: /tmp
    server: 172.17.0.2

 

수정

controlplane ~ ➜  cat pvc.yaml 
apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-analytics
spec:
  capacity:
    storage: 100Mi
  volumeMode: Filesystem
  accessModes:
    - ReadWriteMany
  hostPath:
    path: /pv/data-analytics