To speed up instance spawning we need an image in wmflabs that comes with most packages / puppet work already done, then the instance first boot will be way faster (it takes up to two hours to install everything currently).
The process is to use a Trusty instance as the build host then use the labs_vmbuilder puppet module to bring in the image creation utility and manifests. The process is documented at https://wikitech.wikimedia.org/wiki/OpenStack#Building_Ubuntu_images
We will need to hook in it or adjust labs_vmbuilder to be able to inject additional puppet classes to be applied on the image being build.
Aiming for Trusty since that is the system CI is using right now. Andrew told me that the Jessie image build is not fully ready following Jessie release.