Kollaps: decentralized and dynamic topology emulation

The performance and behavior of large-scale distributed applications is highly influenced by network properties such as latency, bandwidth, packet loss, and jitter. For instance, an engineer might need to answer questions such as: What is the impact of an increase in network latency in application response time? How does moving a cluster between geographical regions affect application throughput? What is the impact of network dynamics on application stability? Currently, answering these questions in a systematic and reproducible way is very hard due to the variability and lack of control over the underlying network. Unfortunately, state-of-the-art network emulation or testbed environments do not scale beyond a single machine or small cluster (i.e., MiniNet), are focused exclusively on the control-plane (i.e., CrystalNet) or lack support for network dynamics (i.e., EmuLab).