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CKAD preparation practice #3

Hitesh Pattanayak
12 min readAug 27, 2023

--

In this post we shall solve the challenges section of CKAD course by KodeKloud

Challenge — 1

Below is the architecture asked to deploy

Since the question says that the PersistentVolume jekyll-site has already created, so lets verify:

kubectl get pv

NAME          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS    REASON   AGE
jekyll-site   1Gi        RWX            Delete           Available           local-storage            5m39s

Next since the whole architecture has been create under namespace development, let verify is the namespace exists or not:

kubectl get ns | grep development
development       Active   7m22s

Lets start by deploying/creating other components of the architecture. We will try to use imperative commands wherever necessary to quickly finish the challenge.

Lets deploy PersistentVolumeClaim jekyll-site first. Below are the requirements:

We will require the storageClassName of the PersistentVolume to which we want to attach the PersistentVolumeClaim. So that would be:

kubectl describe pv jekyll-site | grep StorageClass
StorageClass:      local-storage

The manifest pvc.yaml would look like this:

apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: jekyll-site
  namespace: development
spec:
  accessModes:
    - ReadWriteMany
  storageClassName: local-storage
  resources:
    requests:
      storage: 1Gi

Lets create and validate:

# create
kubectl apply -f pvc.yaml

# validate
kubectl get pvc -n development

NAME          STATUS   VOLUME        CAPACITY   ACCESS MODES   STORAGECLASS    AGE
jekyll-site   Bound    jekyll-site   1Gi        RWX            local-storage   6m32s

kubectl get pv
NAME          CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS   CLAIM                     STORAGECLASS    REASON   AGE
jekyll-site   1Gi        RWX            Delete           Bound    development/jekyll-site   local-storage            21m

Both the PersistentVolumeClaim and PersistentVolume have their STATUS as Bound. And the CLAIM of PersistentVolume says it is bound to development/jekyll-site which means it is claimed by PV named jekyll-site in development namespace.

Lets create and deploy Role developer-role Below are the requirements:

The manifest role.yaml would look like this:

apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
  namespace: development
  name: developer-role
rules:
- apiGroups: [""]
  resources: ["pods", "services", "persistentvolumeclaims"]
  verbs: ["*"]

Lets create and validate the role:

# create
kubectl apply -f role.yaml
role.rbac.authorization.k8s.io/development-role created

# validate
kubectl get role -n development
NAME               CREATED AT
development-role   2023-08-12T06:48:01Z

Lets create and deploy RoleBinding developer-rolebinding Below are the requirements:

The manifest binding.yaml would look like this:

apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
  name: developer-rolebinding
  namespace: development
subjects:
- kind: User
  name: martin
  apiGroup: rbac.authorization.k8s.io
roleRef:
  kind: Role
  name: developer-role
  apiGroup: rbac.authorization.k8s.io

Lets create and validate the role:

# create
kubectl apply -f binding.yaml
rolebinding.rbac.authorization.k8s.io/developer-rolebinding created

# validate
kubectl get rolebinding -o wide -n development
NAME                    ROLE                  AGE   USERS    GROUPS   SERVICEACCOUNTS
developer-rolebinding   Role/developer-role   30s   martin

Now lets create the Pod jekyll Below are the requirements:

Lets use imperative commands to generate the Pod manifest:

k run jekyll -n development --image=kodekloud/jekyll-serve --dry-run=client -oyaml > pod.yaml

Then now lets edit and populate other requirements. The final manifest pod.yaml would look like this:

apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: jekyll
  name: jekyll
  namespace: development
spec:
  initContainers:
    - image: kodekloud/jekyll
      name: copy-jekyll-site
      command: ["jekyll", "new", "/site"]
      volumeMounts:
        - name: site
          mountPath: "/site"
  containers:
  - image: kodekloud/jekyll-serve
    name: jekyll
    resources: {}
    volumeMounts:
      - name: site
        mountPath: "/site"
  volumes:
    - name: site
      persistentVolumeClaim:
        claimName: jekyll-site
  dnsPolicy: ClusterFirst
  restartPolicy: Always
status: {}

Lets create and validate the pod:

# create
kubectl apply -f pod.yaml 
pod/jekyll created

# validate
kubectl get po -n development

NAME     READY   STATUS    RESTARTS   AGE
jekyll   1/1     Running   0          33s

Now lets create the Service jekyll Below are the requirements:

Lets use imperative commands to generate the Service manifest:

kubectl expose -n development pod jekyll --name=jekyll --type=NodePort --port=8080 --target-port=4000 --dry-run=client -oyaml > svc.yaml

Then now lets edit and populate the node port. The final manifest svc.yaml would look like this:

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    run: jekyll
  name: jekyll
  namespace: development
spec:
  ports:
  - port: 8080
    protocol: TCP
    targetPort: 4000
    nodePort: 30097
  selector:
    run: jekyll
  type: NodePort
status:
  loadBalancer: {}

Lets create and validate the pod:

# create
kubectl apply -f svc.yaml 
service/jekyll created

# validate
kubectl get svc -n development

NAME     TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
jekyll   NodePort   10.109.111.12   <none>        8080:30097/TCP   31s

curl -v http://10.109.111.12:8080 # should give 200 OK

Now lets update the kube-config file to add user martin and a new context developer. Below are the requirements:

The diff of kube-config file would be as below:

...
contexts:
- context:
    cluster: kubernetes
    user: martin
  name: developer
  namespace: development
...
users:
- name: martin
  user:
    client-certificate: /root/martin.crt
    client-key: /root/martin.key
...

Now lets set the current context to developer context

k config use-context developer
Switched to context "developer".

Now verify if we are able to access pods, services and persistent volumes or not.

Finally check your answer.

Challenge — 3

Below is the architecture asked to deploy

Lets start by deploying/creating other components of the architecture. We will try to use imperative commands wherever necessary to quickly finish the challenge.

since the whole architecture has been create under namespace vote, let verify is the namespace exists or not:

kubectl get ns | grep vote
# no output

Since the vote namespace does not exist, lets create it

kubectl create ns vote

Lets create vote-deployment Below is the requirement:

Lets use imperative commands to create the deployment:

kubectl create deploy -n vote vote-deployment --image=kodekloud/examplevotingapp_vote:before

Verify the pods are in Running state or not:

kubectl get po -n vote -l app=vote-deployment

NAME                              READY   STATUS    RESTARTS   AGE
vote-deployment-8d495c5b7-vj82w   1/1     Running   0          103s

Lets create vote-service Below is the requirement:

Lets use imperative commands to generate the manifest of the service:

kubectl expose -n vote deployment vote-deployment --name=vote-service --type=NodePort --port=5000 --target-port=80 --dry-run=client -oyaml > vote-svc.yaml

Now lets populate the node port in the generated manifest. The final manifest vote-svc.yaml would look like:

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: vote-deployment
  name: vote-service
  namespace: vote
spec:
  ports:
  - port: 5000
    protocol: TCP
    targetPort: 80
    nodePort: 31000
  selector:
    app: vote-deployment
  type: NodePort
status:
  loadBalancer: {}

Lets create and verify the service:

# create
kubectl apply -f vote-svc.yaml 
service/vote-service created

kubectl get svc -n vote
NAME           TYPE       CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
vote-service   NodePort   10.99.180.188   <none>        5000:31000/TCP   9s

curl -v http://10.99.180.188:5000 ## should give 200 OK

Now lets create the redis deployment. Below is the requirement:

Lets use imperative commands to generate the manifest of the deployment:

kubectl create deploy redis-deployment -n vote --image=redis:alpine --dry-run=client -oyaml > redis-deploy.yaml

Now lets edit the manifest and populate the volumes and volumeMounts. The final manifest redis-deploy.yaml would look like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: redis-deployment
  name: redis-deployment
  namespace: vote
spec:
  replicas: 1
  selector:
    matchLabels:
      app: redis-deployment
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: redis-deployment
    spec:
      containers:
      - image: redis:alpine
        name: redis
        resources: {}
        volumeMounts:
          - name: redis-data
            mountPath: /data
      volumes:
        - name: redis-data
          emptyDir: {}
status: {}

Lets create and verify the deployment:

# create
kubectl apply -f redis-deploy.yaml
deployment.apps/redis-deployment created

# verify
kubectl get deploy -n vote

NAME               READY   UP-TO-DATE   AVAILABLE   AGE
redis-deployment   1/1     1            1           80s
vote-deployment    1/1     1            1           13m

Lets create redis-service Below is the requirement:

Lets use imperative commands to create the service:

kubectl expose -n vote deployment redis-deployment --name=redis --type=ClusterIP --port=6379 --target-port=6379

verify the service:

kubectl get svc -n vote

NAME           TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
redis          ClusterIP   10.106.60.131   <none>        6379/TCP         26s
vote-service   NodePort    10.99.180.188   <none>        5000:31000/TCP   10m

Now lets create the worker deployment. Below is the requirement:

Lets use imperative commands to create the deployment:

kubectl create deploy -n vote worker --image=kodekloud/examplevotingapp_worker

verify the deployment:

Now lets create the db deployment: Below is the requirement:

Lets use imperative commands to generate the manifest:

kubectl create deploy -n vote db-deployment --image=postgres:9.4 --dry-run=client -oyaml > db-deploy.yaml

Now lets edit the deployment and populate environment and volumes. The final manifest db-deploy.yaml would look like this:

apiVersion: apps/v1
kind: Deployment
metadata:
  creationTimestamp: null
  labels:
    app: db-deployment
  name: db-deployment
  namespace: vote
spec:
  replicas: 1
  selector:
    matchLabels:
      app: db-deployment
  strategy: {}
  template:
    metadata:
      creationTimestamp: null
      labels:
        app: db-deployment
    spec:
      containers:
      - image: postgres:9.4
        name: postgres
        resources: {}
        env:
          - name: POSTGRES_HOST_AUTH_METHOD
            value: trust
        volumeMounts:
          - name: db-data
            mountPath: /var/lib/postgresql/data
      volumes:
        - name: db-data
          emptyDir: {}

lets create and validate the deployment

# create
kubectl apply -f db-deploy.yaml
deployment.apps/db-deployment created

# validate
kubectl get deploy -n vote

NAME               READY   UP-TO-DATE   AVAILABLE   AGE
db-deployment      1/1     1            1           73s
redis-deployment   1/1     1            1           15m
vote-deployment    1/1     1            1           27m
worker             1/1     1            1           7m42s

Now lets create db service. Below is the requirement:

Lets use imperative commands to create the service:

kubectl expose deploy -n vote db-deployment --name=db --type=ClusterIP --port=5432 --target-port=5432

verify the service:

kubectl get svc -n vote

NAME           TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
db             ClusterIP   10.100.153.37   <none>        5432/TCP         30s
redis          ClusterIP   10.106.60.131   <none>        6379/TCP         16m
vote-service   NodePort    10.99.180.188   <none>        5000:31000/TCP   26m

Now lets create the result deployment Below is the requirement:

Lets use imperative commands to create the deployment:

kubectl create deploy -n vote result-deployment --image=kodekloud/examplevotingapp_result:before

Verify the deployment

# validate
kubectl get deploy -n vote

NAME                READY   UP-TO-DATE   AVAILABLE   AGE
db-deployment       1/1     1            1           7m42s
redis-deployment    1/1     1            1           22m
result-deployment   1/1     1            1           45s
vote-deployment     1/1     1            1           34m
worker              1/1     1            1           14m

Now lets create result service. Below is the requirement:

Lets use imperative commands to generate the service manifest:

kubectl expose deploy -n vote result-deployment --name=result-service --type=NodePort --port=5001 --target-port=80 --dry-run=client -oyaml > result-svc.yaml

Now lets edit and populate the node port. The final manifest result-svc.yaml would look like this:

apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    app: result-deployment
  name: result-service
  namespace: vote
spec:
  ports:
  - port: 5001
    protocol: TCP
    targetPort: 80
    nodePort: 31001
  selector:
    app: result-deployment
  type: NodePort
status:
  loadBalancer: {}

create and verify the service:

# create
kubectl apply -f result-svc.yaml
service/result-service created

kubectl get svc -n vote

NAME             TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)          AGE
db               ClusterIP   10.100.153.37   <none>        5432/TCP         7m19s
redis            ClusterIP   10.106.60.131   <none>        6379/TCP         22m
result-service   NodePort    10.108.38.244   <none>        5001:31001/TCP   16s
vote-service     NodePort    10.99.180.188   <none>        5000:31000/TCP   32m

We have deployed all the components.

Finally check your answer.

Challenge — 4

Below is the architecture asked to deploy

Lets create the persistent volumes.

There are 6 PersistentVolume resources that needs to deployed and all of them similar specifications except for name and path.

Lets create a single manifest to create all the PVs together. Below are the requirements:

The manifest pvs.yaml would like this:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis01
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis01

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis02
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis02

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis03
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis03

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis04
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis04

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis05
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis05

---

apiVersion: v1
kind: PersistentVolume
metadata:
  name: redis06
spec:
  accessModes:
  - ReadWriteOnce
  capacity:
    storage: 1Gi
  hostPath:
    path: /redis06

lets create and verify the persistent volumes:

# create
kubectl apply -f pvs.yaml 
persistentvolume/redis01 created
persistentvolume/redis02 created
persistentvolume/redis03 created
persistentvolume/redis04 created
persistentvolume/redis05 created
persistentvolume/redis06 created

# verify
kubectl get pv

NAME      CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM   STORAGECLASS   REASON   AGE
redis01   1Gi        RWO            Retain           Available                                   52s
redis02   1Gi        RWO            Retain           Available                                   52s
redis03   1Gi        RWO            Retain           Available                                   52s
redis04   1Gi        RWO            Retain           Available                                   52s
redis05   1Gi        RWO            Retain           Available                                   52s
redis06   1Gi        RWO            Retain           Available                                   52s

Now lets create the redis-cluster-service service before stateful set because stateful set requires a service name. Below are the requirements:

The manifest redis-svc.yaml would look like this:

apiVersion: v1
kind: Service
metadata:
  name: redis-cluster-service
spec:
  clusterIP: None
  ports:
  - name: client
    targetPort: 6379
    port: 6379
  - name: gossip
    targetPort: 16379
    port: 16379

create and validate the service

# create
kubectl apply -f redis-svc.yaml 
service/redis-cluster-service created

# validate
kubectl get svc

NAME                    TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)              AGE
kubernetes              ClusterIP   10.96.0.1    <none>        443/TCP              3h22m
redis-cluster-service   ClusterIP   None         <none>        6379/TCP,16379/TCP   6s

Now lets create the redis-cluster stateful-set

Below are the requirements:

The manifest statefulset.yaml would look like this:

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: redis-cluster
spec:
  selector:
    matchLabels:
      app: redis-cluster
  serviceName: redis-cluster-service
  replicas: 6
  template:
    metadata:
      name: redis-cluster
      labels:
        app: redis-cluster
    spec:
      containers:
      - image: redis:5.0.1-alpine
        name: redis
        command: ["/conf/update-node.sh", "redis-server", "/conf/redis.conf"]
        env:
        - name: POD_IP
          valueFrom:
            fieldRef:
              fieldPath: status.podIP
        ports:
        - containerPort: 6379
          name: client
        - containerPort: 16379
          name: gossip
        volumeMounts:
        - name: conf
          mountPath: /conf
          readOnly: false
        - name: data
          mountPath: /data
          readOnly: false
      volumes:
      - name: conf
        configMap:
          name: redis-cluster-configmap
          defaultMode: 0755
  volumeClaimTemplates:
    - metadata:
       name: data
      spec:
        accessModes:
        - ReadWriteOnce
        resources:
          requests:
            storage: 1Gi

create and validate the stateful set

# create
kubectl apply -f statefulset.yaml

statefulset.apps/redis-cluster created

# validate

kubectl get po
NAME              READY   STATUS    RESTARTS   AGE
redis-cluster-0   1/1     Running   0          23s
redis-cluster-1   1/1     Running   0          18s
redis-cluster-2   1/1     Running   0          15s
redis-cluster-3   1/1     Running   0          12s
redis-cluster-4   1/1     Running   0          9s
redis-cluster-5   1/1     Running   0          6s

execute command as mentioned in redis-cluster-config

kubectl exec -it redis-cluster-0 -- redis-cli --cluster create --cluster-replicas 1 $(kubectl get pods -l app=redis-cluster -o jsonpath='{range.items[*]}{.status.podIP}:6379 {end}')

>>> Performing hash slots allocation on 6 nodes...
Master[0] -> Slots 0 - 5460
Master[1] -> Slots 5461 - 10922
Master[2] -> Slots 10923 - 16383
Adding replica 10.244.192.4:6379 to 10.244.192.1:6379
Adding replica 10.244.192.5:6379 to 10.244.192.2:6379
Adding replica 10.244.192.6:6379 to 10.244.192.3:6379
M: 17c25a0bd004f2372c74cf8d9e56b1c70946fd54 10.244.192.1:6379
   slots:[0-5460] (5461 slots) master
M: 98c0922e0a13d3efa9377f3f76c878da843f8a1e 10.244.192.2:6379
   slots:[5461-10922] (5462 slots) master
M: 37ff6f3eb0aca87682296e4bd09d96cd4b88cacb 10.244.192.3:6379
   slots:[10923-16383] (5461 slots) master
S: 86ae291916b863e0cd5b132579eaf9f33343fa59 10.244.192.4:6379
   replicates 17c25a0bd004f2372c74cf8d9e56b1c70946fd54
S: 83e503793a6845e776211df61d274b98bc1a5837 10.244.192.5:6379
   replicates 98c0922e0a13d3efa9377f3f76c878da843f8a1e
S: d889b408104efba53a9800d8eb8944e193008a04 10.244.192.6:6379
   replicates 37ff6f3eb0aca87682296e4bd09d96cd4b88cacb
Can I set the above configuration? (type 'yes' to accept): yes
>>> Nodes configuration updated
>>> Assign a different config epoch to each node
>>> Sending CLUSTER MEET messages to join the cluster
Waiting for the cluster to join
........
>>> Performing Cluster Check (using node 10.244.192.1:6379)
M: 17c25a0bd004f2372c74cf8d9e56b1c70946fd54 10.244.192.1:6379
   slots:[0-5460] (5461 slots) master
   1 additional replica(s)
S: d889b408104efba53a9800d8eb8944e193008a04 10.244.192.6:6379
   slots: (0 slots) slave
   replicates 37ff6f3eb0aca87682296e4bd09d96cd4b88cacb
M: 98c0922e0a13d3efa9377f3f76c878da843f8a1e 10.244.192.2:6379
   slots:[5461-10922] (5462 slots) master
   1 additional replica(s)
S: 83e503793a6845e776211df61d274b98bc1a5837 10.244.192.5:6379
   slots: (0 slots) slave
   replicates 98c0922e0a13d3efa9377f3f76c878da843f8a1e
S: 86ae291916b863e0cd5b132579eaf9f33343fa59 10.244.192.4:6379
   slots: (0 slots) slave
   replicates 17c25a0bd004f2372c74cf8d9e56b1c70946fd54
M: 37ff6f3eb0aca87682296e4bd09d96cd4b88cacb 10.244.192.3:6379
   slots:[10923-16383] (5461 slots) master
   1 additional replica(s)
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

We have deployed all the components.

Finally check your answer.

Folks, if you like my content, would you consider following me on LinkedIn.

K8s
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Kodekloud
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Hitesh Pattanayak
Hitesh Pattanayak

Written by Hitesh Pattanayak

221 Followers
55 Following

Senior Product Engineer @ Infracloud Technologies | 7 years of experience | Polyglot | Backend Developer | Kubernetes and AWS practitioner | Finance Enthusiast

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