It's always difficult to know when to release, and we really wanted to do it earlier. But it seems that each week more awesome work was being done in Gnocchi, so we kept delaying it while having no pressure to push it out.
But now that the OpenStack cycle is finishing, even Gnocchi does not strictly follow it, it seemed to be a good time to cut the leash and leave this release be.
There are again some major new changes coming from 3.0. The previous version 3.0 was tagged in October and had 90 changes merged from 13 authors since 2.2. This 3.1 version have 200 changes merged from 24 different authors. This is a great improvement of our contributor base and our rate of change – even if our delay to merge is very low. Once again, we pushed usage of release notes to document user visible changes, and they can be read online.
Therefore, I am going to summary quickly the major changes:
The REST API authentication mechanism has been modularized. It's now simple to provide any authentication mechanism for Gnocchi as a plugin. The default is now a HTTP basic authentication mechanism that does not implement any kind of enforcement. The Keystone authentication is still available, obviously.
Batching has been improved and can now create metrics on the fly, reducing the latency needed when pushing measures to non-existing metrics. This is leveraged by the collectd-gnoccchi plugin for example.
The performance of Carbonara based backend has been largely improved. This is not really listed as a change as it's not user-visible, but an amazing work of profiling and rewriting code from Pandas to NumPy has been done. While Pandas is very developer-friendly and generic, using NumPy directly offers way more performance and should decrease
gnocchi-metricdCPU usage by a large factor.
The storage has been split into two parts: the storage of incoming new measures to be processed, and the storage and archival of aggregated metrics. This allows to use e.g. file to store new measures being sent, and once processed store them into e.g. Ceph. Before that change, all the new measures had to go into Ceph. While there's no specific driver yet for incoming measures, it's easy to envision a driver for systems like Redis or Memcached.
I will write more about some of these new features in the upcoming weeks, as they are very interesting for Gnocchi's users.
We are planning to run a scalability test and benchmarks using the ScaleLab in a few weeks if everything goes as planned. I will obviously share the result here, but we also submitted a talk for the next OpenStack Summit in Boston to present the results of our scalability and performance tests – hoping the session will be accepted.
I will also be talking about Gnocchi this Sunday at FOSDEM.
We don't have a very determined roadmap for Gnocchi during the next weeks. Sure we do have a few ideas on what we want to implement, but we are also very easily influenced by the requests of our user: therefore feel free to ask for anything!