When you run your application on the public network, you need an infrastructure such as networks, Virtual Machines, and storage. Obviously, companies borrow or build their own data center to prepare those infrastructures, and then hire data center engineers and operators to monitor and manage those resources.
However, purchasing and maintaining those assets need a large capital expense; you also need an operation expense for data center engineers/operators. You also need a read time to fully set up those infrastructures, such as buying a server, mounting to a data center rack, cabling a network, and then the initial configuration/installation of the OS, and so on.
Therefore, rapidly allocating an infrastructure with appropriate resource capacity is one of the important factors that dictates that success of your business.
To make infrastructure management easier...