I may have overstated then. From rwmj's comment that "every distro except Ubuntu has to set up an external CI server in order to get their drivers and changes

I may have overstated then. From rwmj's comment that "every distro except Ubuntu has to set up an external CI server in order to get their drivers and changes in" I gathered that Ubuntu was the distro of choice for CI, so that's what I should have written: for CI. I didn't mean to say that Ubuntu is the OpenStack project's preferred choice for deployment.