Update: This does not apply to Icehouse. This flag was to activate an experimental feature -this option no longer exists in Icehouse. (It is in Havana, however).
There have been some criticisms of the implementation of Ceilometer (or Telemetry as of Icehouse) – however, it’s still the main show in town for understanding what’s going on inside your Openstack.
We’ve been doing a bit of work with it in multiple projects. In one of our efforts – pulling in energy info via kwapi – we noticed that Ceilometer really crawls to a halt with the API giving a response in 20s when trying to enter just a single energy consumption data point. (Yes, it might make more sense to batch these up…). For our simple scenario, this performance was completely unworkable.
Our Ceilometer installation just used the basic Mirantis Fuel v4.0 which installed a variant of Havana. The db backend was mysql (chosen by Fuel) and we just went with the default configuration parameters.
There are known performance issues with Ceilometer (issue, presentation mentioning it, mailing list discussion) and it seems that Icehouse has made some significant strides in improving performance of Ceilometer/Telemetry; however, we have not managed to perform the upgrade as yet – maybe some of these issues have already been fixed.
For our work, we were able to significantly improve the performance of the Ceilometer API by activating (experimental!) thread pooling on the db: this had the effect of making entering single energy consumption data points take less than one second (down from 20s) and a larger query of the list of available meters took 5s compared to a previous 34s. It just involved setting
use_tpool=true
in /etc/ceilometer/ceilometer.conf and bingo – significant uptick in performance (for our small, experimental system).
Not sure how widely applicable this is, and not sure if it’s realistic for production environments – for our experimental system, it turned an unworkable system into something which is usable (but certainly not speedy!)
And a few hours later, Mirantis released Fuel 5.0 in which Ceilometer/Telemetry has a mongodb backend…