Customer simply needs to choose the instance (D12_v2 or FS4, for example), the datacenter (Europe West, for example), the Term (1 or 3-year) and the assignment level (company or department). Customers do not need to decide the Operating System (Windows or Linux) at the time of purchase.
While RIs require making upfront commitments on compute capacity, they also provide flexibility should your business needs change. Easily exchange or cancel RIs at any time.
All VM series will have Reserved Virtual Machines Instance availability with the exception of the A-series, Av2-series and G-series virtual machines
All global data centers will have RIs, excluding the sovereign clouds:
All global countries will have the RIs except the counties in the list below.
Argentina, Brazil, Hong Kong, India, Indonesia, Liechtenstein, Malaysia, Mexico, Russia, Saudi Arabia, South Africa, and Turkey.