As done with previous OS X images, we will need to build an installer image which can be used to install OS X 10.10. From that, we can build a base image to be used with deploystudio. It seems ever flavor of OS X that is released has some changes to the installer and how it is stored in the installer app. It will probably take some hacking to extract the installer from the app downloaded from the app store.
The current developer build is: Preview 6 Posted Date: Aug 18, 2014 Build: 14A329f
For some reason, when I redeemed the download code for Preview 6 it began downloading Preview 5. This won't really matter since a new base image will need to be built before production use anyway.
Using the createinstallmedia tool, I built a bootable dmg image for installing OSX 10.10 Yosemite. Just need to test it and find a place to store it. sudo /Applications/Install\ OS\ X\ Yosemite\ Developer\ Preview.app/Contents/Resources/createinstallmedia --volume /Volumes/Untitled --applicationpath /Applications/Install\ OS\ X\ Yosemite\ Developer\ Preview.app --nointeraction
The bootable installer image had some problems that prevented it from making the target install disk bootable. I've skipped that step for the time being and moved on to the base image which has been created and uploaded to install.test.releng.scl3.m.c for testing. /Deploy/Masters/HFS/yosemite-preview-5-base-20140826.hfs.dmg
At this point, 10.10 refuses to boot after an image deployment. The workflow executes correctly but fails to boot into the final runtime env before rebooting again to the new OS image. I'm starting to suspect the fault is in the images I've been creating with diskutil. The next step is to install 10.10 on the loaner mini's second disk and then capture it using deploystudio. Deploystudio probably does some voodoo with the image after is has been captured to make it boot properly.
Success! I have a 10.10 base image that successfully deploys and boots. (yosemite_Build_14.09.09_13.54.i386.hfs.dmg) I was correct about the DS voodoo. DS does some behind the scene conversions of the image before uploading it to the server. I couldn't tell what those were since it is closed source but I did see system calls to hdiutil and asr.