1. An apparatus for validating application deployment topology in a cloud computing environment comprising: a topology skeleton generator configured to generate, based on multiple VMs and script packages running on the VMs created by a user and required to deploy an application of the user as well as running order of the script packages and data dependency between the script packages set by the user, a topology skeleton that comprises at least scripts of script packages of respective VMs and running order of the script packages, wherein the script comprises an import method for getting input parameters from the outside and an export method for exporting parameters to the outside; and a simulator configured to simulate a runtime environment in the cloud computing environment at the apparatus, thereby validating the running order and data dependency with respect to the topology skeleton, wherein the simulator is installed in the apparatus by using a simulator installation package retrieved from the cloud computing environment, and wherein validating data dependency comprises running the import method and the export method in respective scripts to check parameters defined in the import method and export method.