1. A method for managing life-cycles of a “software as a service” (SaaS) software application, comprising: installing the SaaS software application in a system landscape on a computer server, the system landscape containing at least an application server and a database (DB) server; separating system data for the SaaS software application from customer data for the SaaS software application and storing the system data and customer data in different databases; creating a virtual machine (VM) image for the system landscape, the VM image to include the databases containing system data and exclude the databases containing the customer data; deploying the SaaS software application to one or more computer servers by loading VMs on one or more computer servers based on the VM image; when the SaaS software application is to be upgraded to a new version, preparing a new VM image with the new version of the SaaS software application and deploying the new version of the SaaS software application by loading VMs on the one or more computer servers based on the new VM image.