1. Business Background Once an enterprise reaches a certain scale, relying entirely on public cloud infrastructure makes IT costs very high. The cost of purchasing physical machines can be amortized over the next 3 to 5 years, and afterwards the machines are not scrapped; instead they continue to serve beyond their planned lifespan.

1. User Scenarios for Hybrid Cloud 1.1 Handling Explosive Business Growth Internet businesses grow exponentially, and it is hard to predict how much infrastructure capacity to reserve. Usually, for a long stretch in the early days of a business, a small colocation footprint of physical machines is enough to meet demand.