A performance testing and stress testing of cloud platform central identity: Openstack Keystone case study

Nowadays OpenStack platform is a leading solution in cloud computing field. Keystone, the OpenStack Identity Service, is one of its major components. This service is responsible for authentication and authorization of users and services of the system. Keystone is a high-load service since all interactions between services happen through it. This leads us to the following problem: increasing the number of cloud service users results to significant load growth. In this paper we demonstrate the problem of Keystone performance degradation during constant load. In order to find source of the problem we have tested Keystone with different backends (PostgreSQL, MariaDB), frontends (Apache2, ngnix) and keeping the database on different hardware (HDD, SSD and tmpfs on RAM). Using different configuration sets is necessary because it helps us to narrow the amount of possible reasons causing degradation. Tests were conducted with Rally. As a result, in all test cases we have seen inadequate quick degradation under relatively light load. We have also implemented a mock service which represents the simplest Keystone tasks. Our service turned out to be much faster than Keystone. The problem with Keystone might be related to either its internal logic implementation or incorrect interaction with other components; it is the subject of further research.