Sooner or later, it becomes obvious that running a large number of the IT portfolio—perhaps even the majority of it—in the cloud makes sense from a variety of perspectives. In most cases, running in the cloud provides substantial cost savings; reduces or eliminates the need for an enterprise to maintain its own datacenters; reduces or eliminates the need to manage hardware and software updates; and enables the sort of innovation we discussed in Chapter 1. The cloud is very compelling; yet the migration phase typically involves many more applications and many more people, and potentially impacts more of IT’s customers than any other—by far