Answer By Deepseek

The correct answer is:

A. Assign appropriate access for Google services to the service account used by the Compute Engine VM.

Explanation:

When migrating an application to Google Cloud Compute Engine, the recommended practice for authentication is to use the service account associated with the Compute Engine VM. Here’s why option A is the best choice:

1. Application Default Credentials (ADC) on Compute Engine:

   • When running on Compute Engine, ADC automatically uses the service account attached to the VM instance for authentication. This requires no additional configuration or code changes in your application.

2. Minimal Changes:

   • Since your application already uses ADC, it will seamlessly work on Compute Engine without requiring any changes to the application code or configuration files. You only need to ensure that the service account assigned to the VM has the appropriate permissions for the Google Cloud services your application uses.

3. Google-Recommended Practice:

   • Using the service account associated with the VM is a Google-recommended practice for authentication on Compute Engine. It eliminates the need to manage and secure credential files manually.

Why Not the Other Options?

• B. Create a service account with appropriate access for Google services, and configure the application to use this account:

  • While this approach works, it is unnecessary in this scenario. The default service account attached to the VM can be used directly, and creating a new service account would require additional configuration changes.

• C. Store credentials for service accounts with appropriate access for Google services in a config file, and deploy this config file with your application:

  • This approach is not recommended because it involves managing and securing credential files manually. It also requires changes to your application to load the credentials from the config file.

• D. Store credentials for your user account with appropriate access for Google services in a config file, and deploy this config file with your application:

  • This approach is not recommended for production environments. Using user account credentials in a config file is insecure and not scalable. It also requires manual management of credentials.

Conclusion:

Option A is the best approach because it leverages the default service account attached to the Compute Engine VM, aligns with Google-recommended practices, and requires minimal changes to your application.