Some apps are easy to move to the cloud. Some apps are born there. Some… aren’t. A scenario a lot of us see as we migrate workloads is that we end up with shiny automated hotness in the cloud and then a bunch of old busted apps running on-prem.
Alternatively, if you work with more traditional IT and don’t know where to start, migrating workloads can feel daunting. Designing for cloud requires a lot more abstraction than on-prem. You’re much further from the metal.
Multi-tiered apps are usually an easy fit for cloud. But what do you do with all the client-server junk? — off-the-shelf apps that run on a single server, can’t be scaled horizontally, and are supported by vendors who still freak out about virtualization.