This is one of several, large Russian military bases inside Ukraine.
Close to the Ukrainian/Russian border, this ones located near the town of Krasnyi Luch. Like others, it has a training area, permanent buildings and large combat unit stationed there.
July 2017 satellite images show approx – 200 Russian tanks, various forms of artillery, multiple launch rocket systems, armoured personnel carries, armoured fighting vehicles and cargo trucks. Now if you think that’s impressive, there’s another even larger base & combat unit at the nearby town of Torez (see map). To enter/exit Ukraine, all Russian forces in the area use the remote, Russian controlled Marynivka border crossing.
Note Krasnyi Luch is in Ukraine’s Luhansk Oblast (province) and Torez the Donetsk Oblast. This shows why the Marynivka crossing is vital to Russia’s occupation of eastern Ukraine. Through it, it’s able to send supplies and forces into both the occupied regions of Donetsk and Luhansk.
Units such as those at Krasnyi Luch are Russia’s mobile defence force. Should Ukraine attack its occupied territory, they will move to support front line Russian forces and attempt to counter any Ukrainian breakthroughs.