Host Filesystem Impact on Tempest Performance in OpenStack

As I mentioned in a previous post, about a year ago I picked up a 1U server from EBay to use as a local single-node OpenStack environment. In general I was quite happy with it, but at some point I got tired of paying for electricity to run a fairly power-hungry server that sits idle, or close to it, about 95% of the time. The fans also picked up an annoying whine somewhere along the line, so once I discovered how much more efficient a modern desktop processor would be, while actually performing better than the old dual server ones, I decided it was time for a new box. This post will be the story of my journey to get Tempest running in an acceptable fashion on it, and what I learned along the way.

Debugging Syntax and Import Errors in OpenStack Unit Tests

Most OpenStack projects use a combination of tox, testr, and subunit to run their unit tests. This works fine as long as you don't have any simple errors in your code, such as a typo in an import or a missing closing paren. In those cases testr or subunit may swallow the error and you won't know exactly where it is (I hear this may be fixed in some version of the tools, but the one I'm currently using still has this limitation). To fix this, we need another way to run unit tests that will expose the actual error to us.

Using a Branch Under Review in TripleO

One of the unintended consequences of Feature Freeze in OpenStack is that a lot of new features get merged in a hurry at the end of the cycle. That's obviously not ideal, but it's a reality we all have to live with for now. TripleO has been bitten by this a few times recently, and the long gate queue that also goes along with Feature Freeze means sometimes fixes for problems take a long time (days) to merge in the other projects. In the gate we have tempreverts and cherry-picks to mitigate that problem, but for local devtest those features are not available. Fortunately there's another solution.

Juno Summit Thoughts

I attended my first OpenStack Summit in Atlanta last week, and now that I'm (mostly) recovered I wanted to write down some of my thoughts about the experience.

My Devtest Workflow

I said in a previous post that I would write something up about my devtest workflow once I had it nailed down a bit more, and although it's an always-evolving thing, I think I've got a pretty good setup at this point so I figured I'd go ahead and write it up. Instead of including scripts and such here, I'm just going to link to my Github repo where all of this stuff is stored and reference those scripts in this post.

Python 2.6 and Tox

Just ran into an issue running tox in diskimage-builder on a CentOS 6.5 instance I booted to test a change that failed the python26 gate test, so I thought I'd post the fix in case anyone else hits the same thing.

Using pypi-mirror with devtest

A full run of TripleO's devtest takes a long time - around an hour or more on my i7/16GB box even with a hot squid cache. Quite a bit of the time is spent building images, and there are a few ways to speed that up, some of which are easier than others.

OpenStack Development System Setup

I've been meaning to write something up about how I set up my OpenStack development environment because there are some handy things you can do before you even get started that will likely save you some hassle down the line. I've recently discovered that there are rather varied ways other people are doing this sort of thing, so keep in mind that this isn't the "right" way, it isn't the best way, but it's what works for me.

PSA: Review Requests

Since this comes up on a fairly regular basis, please note that community policy says review requests should not be posted to the openstack-dev list. For details and the correct methods to use, see Thierry's mailing list entry on the topic:

As an added bonus, now I don't have to search the archives to find that when I need to link someone to it. :-)


Things I Thought I Knew

It's been a humbling week for me. Which is good because it means I'm learning things, but I will admit it would be nice to not find out I'm completely wrong about quite so many things in such a short span of time. I figured I would share what I've learned so it might be useful to someone else, because evidently it wasn't obvious to me.


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