Existing Software is migrated to the cloud. This stage does not require any changes to the Software itself.
The underlying architecture of the migrated Software is optimized for the Cloud. Every task that is typically handled by operations staff, is automated. Examples: Datacenter failover, capacity scaling, monitoring and alerting.
The Software is broken down from one big monolith to an ecosystem of microservices. Every microservice is developed, tested, deployed and scaled independently.
Serverless removes the need to manage any servers, operating systems or runtime environments. This is the current optimum of scaleability, cost effectiveness and fast development cycles.