Using Infrastructure as a Service (IaaS) is the appropriate solution for deploying Azure virtual machines because IaaS offers the benefit of providing and managing the underlying infrastructure such as virtual servers, storage, and networking, while still allowing you to maintain control over the operating systems and applications. This makes it suitable for tasks that require flexibility and control over the computing environment.
To host the web apps, the Standard web tier plan is the most appropriate choice. It supports custom domains, offers sufficient storage of up to 50 GB, provides dedicated compute instances, and includes load balancing between instances—all essential for the requirements. Additionally, while the Basic plan offers some of the needed features, it does not support load balancing and has limited instance support, which makes it a less viable option. Hence, the Standard plan meets all the specified requirements more comprehensively.
The solution does not meet the goal. Using several Azure Active Directory (Azure AD) directories to segment Azure resources for each division is not efficient and increases administrative complexity. Instead, a more effective approach would be to utilize Azure Resource Manager to create separate resource groups for each division. This allows for resource segregation while maintaining centralized management. Additionally, Azure Role-Based Access Control (RBAC) can be used to assign appropriate permissions to each division's administrator within the same Azure AD directory, thereby minimizing administrative effort.
The web tier plan that meets all the specified requirements is the Standard plan. It supports using a custom domain (miami.weyland.com), allows deployment to multiple instances, includes SSL support, and offers sufficient storage (more than 12 GB). While it may not be the lowest cost option, it provides the necessary features and capacity required for the web app, making it the most appropriate choice.
The term 'elastic expenditure model' is not a recognized expenditure model in Azure or cloud computing in general. The correct expenditure models in Azure include 'pay-as-you-go' and 'reserved instances.' 'Pay-as-you-go' is appropriate for a flexible and scalable usage model where you pay based on resources consumed. In this scenario, migrating virtual machines to an Azure pay-as-you-go subscription meets the requirements for using a flexible payment approach. Therefore, the suggested solution does not meet the goal.