In this paper, we present TREX, a novel tenant-driven network traffic extraction platform for SDN-based cloud environments. With TREX, tenants can define templates that consist of extraction point, fine-grained network traffic filter and a target identifier representing a tenant-operated analysis application. All packets that match on the filter will be extracted in a lightweight fashion at a virtual switch and forwarded to the analysis application in near real time. Therefore, TREX enables analysis and debugging based on proprietary applications that are operated directly by the tenant. Furthermore, original network traffic remains unaffected and migration of extraction points to different physical cloud nodes, which is typical for cloud environments, will not lead to a gap in the extraction.