Designing and Implementing Microsoft DevOps Solutions (AZ-400) Practice

Using Azure Key Vault is the best method to prevent a deployment user from viewing account credentials in an Azure Resource Manager (ARM) template. Azure Key Vault is specifically designed to securely store and manage sensitive information, such as passwords, API keys, and other secrets. By storing credentials in Key Vault and referencing them in the ARM template, you can ensure that sensitive data is not hardcoded or exposed directly within the template itself.

The principal advantages of utilizing Azure Key Vault include robust access control, logging, and management features that enable you to define who can access specific secrets. The deployment process can fetch the required credentials from Key Vault at runtime, thus keeping them secure and preventing unauthorized access or visibility.

In contrast, the other options do not provide the same level of security for sensitive information. A Web.config file and Appsettings.json file are typically used for application configuration, but they can be easily read by anyone with access to the codebase or server. Azure Storage tables might be used for data storage but do not offer the specific security features that Key Vault provides for sensitive credential management. Thus, using Azure Key Vault greatly enhances security during deployment, keeping sensitive information properly protected.