Linux Foundation Certified Kubernetes Application Developer : CKAD valid dump

Correct Answer:

See the solution below.
Explanation:
To allow a pod to send and receive traffic only to and from specific pods, you can use network policies in Kubernetes.
First, you will need to create a network policy that defines the allowed traffic. You can create a network policy yaml file with the following rules:
apiVersion: networking.k8s.io/v1
kind: NetworkPolicy
metadata:
name: newpod-network-policy
namespace: default
spec:
podSelector:
matchLabels:
app: kdsn00201-newpod
ingress:
- from:
- podSelector:
matchLabels:
app: web
- podSelector:
matchLabels:
app: storage
This policy will only allow incoming traffic to the pod with the label app=kdsn00201-newpod from pods with the label app=web or app=storage. If you have different labels on your web and storage pods please update the matchLabels accordingly.
Once you have created the network policy, you can apply it to the cluster by running the following command:
kubectl apply -f <network-policy-file>.yaml
This will apply the network policy to the cluster, and the newpod will only be able to send and receive traffic to and from the web and storage pods.
Please note that, NetworkPolicy resource is not available by default, you need to enable the NetworkPolicy feature on your Kubernetes cluster. This feature is enabled by default on some clusters and must be explicitly enabled on others. You can check if NetworkPolicy is available by running the command kubectl api-versions
| grep networking
Also, you need to ensure that the pods that you want to allow traffic to and from are running on the same namespace.

Correct Answer:

See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Define Network Policy for Nginx Service:
- Create a NetworkPoliCY named 'nginx-policy' that allows traffic from pods labeled 'app=nginx' to pods labeled Sapp-apps
- Use 'ingress' rules to define incoming traffic to the nginx service-
- Specify the for the nginx service.
- Allow all ports.

2. Define Network Policy for App Service: - Create a NetworkP01iCY named 'app-policy' that allows traffic from pods labeled 'app=app' to pods labeled 'app=database' - Use 'ingress' rules to define incoming traffic to the app service. - Specify the 'podSeIector' for the app service. - Allow traffic on the port that the database service listens on.

3. Create the NetworkPolicy Objects - Apply the NetworkP01iCies using the 'kubectl apply' command: bash kubectl apply -f nginx-policy.yaml kubectl apply -f app-policy.yaml 4. Apply Default Network Policy: - Create a NetworkPoliCY named 'default-policy' that blocks all traffic by default. - This ensures that only traffic allowed by the specific policies is permitted.

5. Apply Default Network Policy: - Apply the NetworkPoliCY using the 'kubectl apply' command: bash kubectl apply -f default-policy_yaml This configuration ensures that: - Nginx Service: Can access the 'app' service on port 80, and no other traffic is allowed in or out. - App Service: Can access the 'database' service on port 5432, and no other traffic is allowed in or out - All Other Pods: All other pods in the cluster are blocked from communicating with each other by the default network policy.,

Correct Answer:

See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create a new Deployment with updated image:
- Create a new Deployment named 'mysql-deployment-new' with the updated MySQL image. You can either create a new YAML tile or use 'kubectl create deployment' command.
- Ensure that the new deployment has the same number ot replicas as the old deployment.

2. Apply the new Deployment: - Apply the new Deployment YAML using 'kubectl apply -f mysql-deployment-new.yamr 3. Check Deployment status: - IJse ' kubectl get deployments' to verity that both deployments are running. You should see both 'mysql-deployment' and 'mysql-deployment-new' . 4. Update Service to use the new deployment: - Update the Service that is associated with the MySQL database to point to the new Deployment

- Apply the updated Service YAML using 'kubectl apply -f mysql-service-yamr 5. Verify traffic routing: - Test the application or services that rely on the MySQL database to ensure that the traffic is now being routed to the 'mysql-deployment-new' 6. Delete old Deployment: - Once you have verified that the traffic is successfully routed to the new Deployment, you can delete the old Deployment 'mysql-deployment' using 'kubectl delete deployment mysql-deployment'.]

Correct Answer:

See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create a Secret:
- Create a secret to store your sensitive data using 'kubectl create secret generic my-secret -from
- This command creates a secret named 'my-secret' with two key-value pairs: 'username' and 'password'
- Replace the values with your actual sensitive data.
2. Create a ServiceAccount
- Create a ServiceAccount using 'kubectl create serviceaccount my-service-account
- This command creates a ServiceAccount named 'my-service-account'
3. Create a Role:
- Create a Role to define the permissions for the ServiceAccount. This role will grant access to the secret.
- Create a Role named 'my-role' using the following YAML:

- Save this configuration in a file named 'my-role.yamr and apply it to your cluster using 'kubectl apply -f my-role-yamp - Replace 'default' With the namespace where your secret is created. 4. Bind the Role to the ServiceAccount: - Bind the created Role to the ServiceAccount using 'kubectl create rolebinding my-role-binding -role-my-role account'. - This command creates a RoleBinding named 'my-role-binding' which binds the 'my-role' to the 'my-service-account' in the 'default' namespace. - Replace 'default' With the namespace where your secret is created. 5. Verify Permissions: - You can verify the ServiceAccount's access to the secret using 'kubectl auth can-i get secrets -as-my-service-account --namespace=default' - This command should return 'yes' if the ServiceAccount has the necessary permissions. 6. Use the ServiceAccount in your Pod: - Use the ServiceAccount within your Pod's specification to grant the application access to the secret. - Add a 'serviceAccountNames field Within your Pod specification pointing to tne created ServiceAccount.

Now your application running in the Pod will have access to the secret 'my-secret using the environment variables defined in the 'envFror-n' section. The ServiceAccount 'my-service-account is configured with the least privilege principle, ensuring that it can only access the necessary data. ,

Correct Answer:

See the solution below.
Explanation:
Solution:
To update the nginxsvc service to serve on port 5050, you will need to edit the service's definition yaml file.
You can use the kubectl edit command to edit the service in place.
kubectl edit svc nginxsvc
This will open the service definition yaml file in your default editor. Change the targetPort of the service to
5050 and save the file.
To add an HAproxy container named haproxy bound to port 90 to the poller pod, you will need to edit the pod's definition yaml file located at /opt/KDMC00101/poller.yaml.
You can add a new container to the pod's definition yaml file, with the following configuration:
containers:
- name: haproxy
image: haproxy
ports:
- containerPort: 90
volumeMounts:
- name: haproxy-config
mountPath: /usr/local/etc/haproxy/haproxy.cfg
subPath: haproxy.cfg
args: ["haproxy", "-f", "/usr/local/etc/haproxy/haproxy.cfg"]
This will add the HAproxy container to the pod and configure it to listen on port 90. It will also mount the ConfigMap haproxy-config to the container, so that haproxy.cfg is available at /usr/local/etc/haproxy/haproxy.
cfg.
To inject the configuration located at /opt/KDMC00101/haproxy.cfg to the container, you will need to create a ConfigMap using the following command:
kubectl create configmap haproxy-config --from-file=/opt/KDMC00101/haproxy.cfg You will also need to update the args of the poller container so that it connects to localhost instead of nginxsvc. You can do this by editing the pod's definition yaml file and changing the args field to args:
["poller","--host=localhost"].
Once you have made these changes, you can deploy the updated pod to the cluster by running the following command:
kubectl apply -f /opt/KDMC00101/poller.yaml
This will deploy the enhanced pod with the HAproxy container to the cluster. The HAproxy container will listen on port 90 and proxy connections to the nginxsvc service on port 5050. The poller container will connect to localhost instead of nginxsvc, so that the connection is correctly proxied to the new service endpoint.
Please note that, this is a basic example and you may need to tweak the haproxy.cfg file and the args based on your use case.