CKAD試験無料問題集「Linux Foundation Certified Kubernetes Application Developer 認定」

You have a custom resource definition (CRD) named that represents a database resource in your Kubernetes cluster. You want to create a custom operator that automates the creation and management of these database instances. The operator should handle the following:
- Creation: When a new 'database.example.com' resource is created, the operator should provision a new PostgreSQL database instance on the cluster-
- Deletion: When a 'database.example_com' resource is deleted, the operator should clean up the corresponding PostgreSQL database instance.
- Scaling: If the 'spec-replicas' field of the 'database-example.com' resource is updated, the operator should scale the number of database instances accordingly.
Provide the necessary Kubernetes resources, custom operator code, and steps to implement this operator. You should use the 'Operator Framework' to build and deploy this operator
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create the CRD:

- Apply this YAML file to your cluster using ' kubectl apply -f database-crd.yamr. 2. Create the Operator Project: - IJse the Operator Framework' to initialize a new operator project bash operator-sdk init -domain example.com -repo example.com/database-operator --version VO.O. I -license apache2 - Replace 'example_com' with your desired domain name. 3. Define the Custom Resource: - Create a 'database_types.go' file in the 'api/vl' directory of your project. - Define the 'Database' resource as a custom resource struct Go package v1 import ( metavl "k8s.iofapimachinery/pkg/apis/meta/v1" // DatabaseSpec defines the desired state of Database type DatabaseSpec struct { If Replicas specifies the number of database instances to run.

// Password is the password for the database users.

} // DatabaseStatus defines the observed state of Database type DatabaseStatus struct { // Replicas is the actual number of database instances running.

// Ready indicates if the database is ready to accept connections.

}

4. Implement the Controller Logic: - Create a 'database_controller.go' file in the 'controllers' directory- - Implement the logic for creating, deleting, and scaling database instances.

5. Build and Deploy the Operator: - Build the operator using the 'operator-sdk build' command: bash operator-sdk build example.com/database-operator:vO.O.I --local - Deploy the operator to your Kubernetes cluster: bash kubectl apply -f deploy/operator.yaml 6. Test the Operator: - Create a new 'database-example-com' resource:

- Apply the YAML file to your cluster: bash kubectl apply -f my-database.yaml - Verify that the operator creates a PostgreSQL database instance. - Test scaling the database by updating the 'spec.replicas' field of the 'database.example.com' resource. - Delete the 'database.example.com' resource and verify that the operator cleans up the database instance. This step-by-step guide demonstrates a basic example of a custom operator using the Operator Framework. You can Kustomize this operator further to handle more complex operations and integrate with other Kubernetes resources. ,
You have a Deployment named 'web-app-deployment that runs 5 replicas of a web application container. You need to ensure that only one pod iS updated at a time during a rolling update. Additionally, you want to set the update strategy so that no more than 2 pods are unavailable at any given time.
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
I). Update the Deployment YAMI-:
- Update the 'replicas' to 5.
- Define 'maxunavailable: 1 ' and 'maxSurge: 2 in the 'strategy.rollingUpdate' section to control the rolling update process.
- Configure a 'strategy.types to 'RollinglJpdate' to trigger a rolling update when the deployment is updated.

2. Create the Deployment: - Apply the updated YAML file using 'kubectl apply -f web-app-deployment-yamr 3. Verify the Deployment: - Check the status of the deployment using 'kubectl get deployments web-app-deployment to confirm the rollout and updated replica count. 4. Trigger the Automatic Update: - Push a new image to the 'web-app-image:latest' Docker Hub repository 5. Monitor the Deployment: - Use 'kubectl get pods -I app=web-app' to monitor the pod updates during the rolling update process. You will observe that one pod is terminated at a time, while one new pod with the updated image is created. Additionally, you'll see that the number of unavailable pods never exceeds 2. 6. Check for Successful Update: - Once the deployment is complete, use "oubect1 describe deployment web-app-deployment' to see that the 'updatedReplicas' field matches the 'replicas' field, indicating a successful update.
You need to configure a Kubernetes deployment to use a secret stored in a different namespace. How can you access the secret in a different namespace, and how can you mount it as a file in your deployment's container?
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
I). Ensure Access to the Secret:
- The service account used by your deployment needs to have read access to the secret in the other namespace. This can be done using a Role and RoleBinding. If the service account already has access, skip to step 2.
- Create a role in the secret's namespace:

- Create a RoleBinding in the secret's namespace:

- Apply the Role and RoleBinding using: bash kubectl apply -f role-yaml kubectl apply -f rolebinding.yaml 2. Modify your Deployment - Update your Deployment YAML file to mount the secret as a file, specifying the namespace:

- Replace 'my-secret with the actual name of the secret and 'secret-namespace with the namespace where the secret is stored. 3. Apply the Updated Deployment: - Apply the updated deployment using: bash kubectl apply -f my-deployment.yaml 4. Access Secret Data: - The secret's data is now mounted in the container at the specified 'mountPatm. You can access the secret's data using the mounted file.]
You are designing a container image for a Pytnon application tnat uses a specific version of a Pytnon library C requests'). You want to ensure that this specific library version is always used, regardless of the host system's installed version. Explain how you would achieve this within your Docket-file.
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Install Library in Dockerfile:
- Utilize the 'COPY' instruction in your Dockerfile to copy a requirements file containing the exact library version you need.
- Use the 'RIJN' instruction to install the library from the requirements file.
- Example:
dockeflle
FROM python:3S
COPY requirements.txt
RUN pip install -r requirements-txt
COPY
CMD ["python", "app.py"l
2. Create Requirements File ('requirements.txt'):
- Create a 'requirements-txt' file within your project directory.
- Add the specific version of tne 'requests' library to this file.
- Example:
Requests==2.28.1
3. Build the Docker Image:
- Construct your Docker image using the Dockeflle.
- Run tne following command: 'docker build -t your-image-name .
4. Run the Container:
- Launch the container in Kubemetes.
- Verify that the 'requests' library with the specified version is successfully used within the container.
You are deploying a new application named 'ecommerce-app' that requires 10 replicas. You want to implement a rolling update strategy that ensures only two pods are unavailable at any given time, while also allowing for the creation of three new poos simultaneously.
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Update the Deployment YAMLI
- Update the 'replicas to 10.
- Define 'maxiJnavaiIabIe: 2 and 'maxSurge: 3' in the 'strategy.roIIingLJpdate section.
- Configure a 'strategy-type' to 'RollinglJpdate' to trigger a rolling update when the deployment is updated.
- Add a 'spec-template.spec.imagePullPolicy: Always' to ensure that the new image is pulled even if it exists in the pod's local cache.

2. Create the Deployment - Apply the updated YAML file using 'kubectl apply -f ecommerce-app-deployment.yaml' 3. Verify the Deployment: - Check the status of the deployment using 'kubectl get deployments ecommerce-app-deployment to confirm the rollout and updated replica count. 4. Trigger the Automatic Update: - Push a new image to the 'example/ecommerce-app:latest' Docker Hub repository. 5. Monitor the Deployment: - Use 'kubectl get pods -l app=ecommerce-apps to monitor the pod updates during the rolling update process. You will observe that two pods are terminated at a time, while three new pods with the updated image are created. 6. Check for Successful Update: - Once the deployment is complete, use 'kubectl describe deployment ecommerce-app-deployment to see that the 'updatedReplicas' field matches the 'replicas' field, indicating a successful update.
You are running a critical application in your Kubernetes cluster, and it requires access to sensitive information stored in a secret To ensure the application only accesses the specific data it needs and avoids potential misuse, you need to configure ServiceAccounts With proper permissions to access the secret. Describe the steps involved in creating a ServiceAccount with the least privilege principle to access the secret Additionally, mention the YAML configuration required for the ServiceAccount and Role.
正解:
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. ,
You have a Deployment that runs a web application. The application requires a specific version ot a library that is not available in the default container image. How would you use an Init Container to install this library before starting the main application container?
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create an Init Container:
- Add an 'initContainerS section to the Deployment's 'spec-template-spec' configuration.
- Define an Init Container with a suitable name (e.g., 'library-installer').
- Specify the image for the Init Container This image should contain the necessary tools and commands to install the required library.
- Replace 'your-library-installer-image:latest with the actual image you want to use.

2. Configure the Main Container: - In the main application container, ensure that the environment variable 'PATH' includes the installation directory of the library installed by the Init Container. - This allows the application to find and use the newly installed library. 3. Apply the Changes: - Apply the updated Deployment configuration using 'kubectl apply -t my-web-app-deployment.yamr. 4. Verify the Installation: - Once the Pods are deployed, you can check the logs of the main application container to confirm that the library is installed and available for use.
You are deploying a sensitive application that requires strong security measures. You need to implement a solution to prevent unauthorized access to the container's runtime environment. How would you use Seccomp profiles to enforce security policies at the container level?
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create a Seccomp Profile:
- Create a new YAML file (e.g., 'seccomp-profile.yaml') to define your Seccomp profile.
- Specify the name of the Seccomp profile and the namespace where it will be applied.
- Define the allowed syscalls for the container. You can use the 'seccomp' tool or the
'k8s.io/kubernetes/pkg/security/apparmor/seccomp' package to generate the profile.

2. Apply the Seccomp Profile: - Apply the Seccomp profile to your cluster using the following command: bash kubectl apply -f seccomp-profile.yaml 3. Deploy Applications with Seccomp Profile: - Update your Deployment YAML file to include the Seccomp profile:

4. Verify the Seccomp Profile: - Check the status of the pods with 'kubectl describe pod - Look for the "Security Context" section and verify that the Seccomp profile is correctly applied. 5. Test the Restrictions: - Try to access system resources or make syscalls that are not allowed by your Seccomp profile. - Verify that the profile is effectively restricting the container's access to system resources.
You have a Deployment named 'my-app' that runs 3 replicas of a Python application. You need to implement a bluetgreen deployment strategy where only a portion of the traffic is directed to the new version of the application initially. After successful validation, you want to gradually shift traffic to the new version until all traffic is directed to it. You'll use a new image tagged for the new version.
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create a new Deployment for the new version:
- Create a new Deployment file called 'my-app-v2.yaml'
- Define the 'replicas' to be the same as the original Deployment.
- Set the 'image' to 'my-app:v2'
- Ensure the 'metadata-name' is different from the original deployment.
- Use the same 'selector.matchLabelS as the original Deployment.
- Create the Deployment using 'kubectl apply -f my-app-v2.yaml'.

2. Create a Service for tne new Deployment: - Create a new Service file called 'my-app-v2-service.yaml'. - Define the 'selector' to match the labels of the 'my-app-v2 Deployment. - Set the 'type' to 'LoadBalancer' or 'NodePort' (depending on your environment) to expose the service. - Create the Service using 'kubectl apply -f my-app-v2-service.yaml"

3. Create an Ingress (or Route) for traffic routing: - Create an Ingress (or Route) file called 'my-app-ingress.yaml' - Define the 'host' to match your domain or subdomain. - Use a 'rules' section with two 'http' rules: one for the original Deployment C my-app-service' in this example) and one tor the new Deployment my- app-v2-service' in this example). - Define a 'path' for each rule to define the traffic routing. For example, you could route 'r to 'my-app-service' and ','v2 to 'my-app-v2-services - Create the Ingress (or Route) using 'kubectl apply -f my-app-ingress.yaml'

4. Test the new version: - Access the my-app.example.com/v2 endpoint to test the new version of your application. - Validate the functionality of the new version. 5. Gradually shift traffic: - You can adjust the 'path' rules in the Ingress (or Route) to gradually shift traffic to the new version. For example, you could define a 'path' like S/v2/beta' and then later change it to '/v2 - Alternatively, you can use a LoadBalancer controller like Kubernetes Ingress Controller (Nginx or Traefik) to configure traffic splitting using weights or headers. 6. Validate the transition: - Continue monitoring traffic and application health during the gradual shift. - Ensure a smooth transition to the new version without impacting users. 7. Delete the old Deployment and Service: - Once all traffic is shifted to the new version and you are confident in its performance, delete the old Deployment and Service C kubectl delete deployment my-app' and 'kubectl delete service my-app-service') to complete the blue/green deployment process. Note: This is a simplified example. In a real production environment, you would likely need to implement additional steps for: - Health checks: Ensure the new version is healthy before shifting traffic. - Rollback: Implement a rollback mechanism to quickly revert to the previous version if needed. - Configuration management: Store and manage configuration settings consistently across deployments. - Monitoring and logging: Monitor the new version for performance and health issues. ,
You have a Kubernetes application that requires configuration values to be injected into the application's environment variables. You want to manage these configuration values centrally and allow for easy updates and versioning. You are considering using Kustomize to achieve this.
正解:
See the solution below with Step by Step Explanation.
Explanation:
Solution (Step by Step) :
1. Create a base configuration file:
- Define the base configuration values in a file named 'base-yaml'

2. Create a Kustomjzation file: - Create a file named ' kustomization.yaml' to define the Kustomize configuration:

3. Create an overlay for development environment - Create a directory named 'dev' and create a 'kustomization.yamr file within it:

- Create a 'patch.yaml' file within the 'devs directory to override the base configuratiom

4. Apply the configuration: - To apply the base configuration, use: bash kubectl apply -k - To apply the configuration for the development environment, use: bash kubectl apply -k dev 5. Verify the configuration: - You can verify the applied configuration by listing the ConfigMaps: bash kubectl get configmaps -n my-app-namespace - You can View tne specific configuration values using Ski-Ibectl get configmap my-app-config -n my-app-namespace -o yaml ,