Step 10. Profiling OpenStack Internals

Rally leverage OSprofiler to generate traces of OpenStack internal calls happening during the run of a scenario. Integration of OSProfiler in Rally can help to dig into concurrency problems of OpenStack which is a huge ecosystem of cooperative services.


Enabling the profiler is based on a shared secret between the clients (here Rally) and the various Openstack services : the HMAC key. In the following we assume that your OpenStack services have been configured to enable OSprofiler and that the secret HMAC key is SECRET_KEY. This key is stored alongside the credentials of your deployment. Once Rally is instructed about the HMAC key, a new trace can be initialized for each iteration of the workload. Rally will then store in its reports a profiler trace id. This id can be finally used to query OSprofiler in order to get the full trace of the iteration.

Registering the HMAC key

You can store your HMAC key in the environment variable OSPROFILER_HMAC_KEY. This variable will be loaded if you create your deployment with the --from-env option.

Alternatively if you create your deployment using the --file option you can add the HMAC key with the following :

  "openstack": {
    "profiler_hmac_key": "SECRET_KEY"

Getting the full trace

A trace id is stored on a per-iteration basis and can be found in the JSON report as-well as the HTML report :


OSProfiler can be asked to generate the full trace using this trace id:

osprofiler trace show --html --out trace.html 941338f6-3d39-4f80-9dba-395d9dbd16bb

Disabling the profiler

Setting enable_profiler = False under the benchmark group in the configuration file will disabled the profiler.