I'm finding the apt-get upgrade procedure slightly frustrating. The fact that running apt-get upgrade will always upgrade you to the latest version is really annoying if you are halfway through upgrading your infrastructure and then a new release is released. We had just got to the point of being happy with the testing of 3.4 and were planning to upgrade everything over Christmas, then 3.5 came out.
First of all, how do other people plan upgrades around this strategy?
Would it be possible for Cumulus to separate releases into seperate repositories, ie so they would look like this in your sources.list:
CumulusLinux-3.4 cumulus upstream
CumulusLinux-3.5 cumulus upstream
So you are control of what version you are on and will upgrade to?