Security Distribution for Linux Clusters

We performed several benchmarking tests in order to verify whether adding options to the IP header affects the overall performance and by how much. One test was to send a UDP packet between nodes of the cluster and measure the performance degradation that consists of the packet security modification on the sending side, including the packet security extracting on the receiving side. The average overhead of adding extra security based on our implementation is 30%. Most of the overhead (around 25%) is related to the IP packet modification based on the IP security option. The remaining overhead (around 5%) is contributed by the security hooks infrastructure in the Linux kernel, such as the socket hooks. As we can see, most of the overhead is related to the IP packet modification based on the IP options, with only a small fraction of the overhead caused by the security hooks infrastructure.

Our future efforts will be directed at improving the IP modification algorithms as we continue to use IP options as the security transport mechanism.

By changing the IP options, we were able to distribute security information to nodes of the cluster with the DSM. We have optimized the IP packet modification and our primary results show significant improvements—the 30% overhead has dropped to 14%. These performance results are promising, and we see more opportunities for further optimizations to attain a lower overhead. Nevertheless, the results demonstrate the challenges facing the development of efficient distributed security. We hope you try out DSI and DSM and send us your feedback.

David Gordon, co-op intern from Sherbrooke University, for his contributions to DSM.