Maybe I will disappoint somebody, but I have to say Russia is not going to leave. Ukraine for Russia it's not like Iraq fro USA or Libya for Europe. First they brought "democracy" to "tyrannized" nations, bomb them, killed thousands of people and then left them in chaos and blood. Ukraine is too close to Russia - even geographically, not to mention vast economical and social links. And after all this mess in Ukraine happened Russia would leave? Don't make me laugh, please.
From the first beginning Russia's intention in respect of Ukraine were to provide its interests through support of allied regions and through re-construction of Ukraine and making it federal state. Then pro-Russian regions would get more political and economical rights and leverages for protecting and increasing their relations with Russia. For example, most of heavy industries in such cities like Zaporozhye, Donetsk and so on depended on Russian orders and these industries suffered from nationalistic turbulence in Kiev. Shortly, Russian plan on Ukraine wasn't to destroy this state. The plan was to have more influence in the whole Ukraine through the regions traditionally inclined towards Russia. And of course to prevent Ukraine from joining the aggressive military block of NATO.
Nevertheless, the things went as they went.
Now Kremlin thinks what to do next. The same as the West thinks, White House thinks and so on. Russia supported peaceful negotiations in Minsk, and the pause in military actions appeared. Now Kiev prepares for new advance and it seems like Donbas militia does nothing, thus Russia is leaving. I think this is wrong opinion.