A source IT-infrastructure hosts a composite application including multiple functional modules connected to each other via communication links. An abstract pattern includes first nodes and first links representing the functional modules and communication links and lacks resource-related data enabling a deployment engine to instantiate a resource for providing a runtime environment. A target IT-infrastructure has assigned a resource catalog including, for each resource available in the target IT-infrastructure, a specification of the resource's capabilities, and includes second nodes and links, each second node being a representation of one or more of the resources of the target IT-infrastructure and including an indication of the capabilities of one or more resources represented by the second node. The first nodes and links of the abstract pattern are iteratively supplemented by the second nodes and second links.