https://en.wikipedia.org/wiki/Minsk_agreements

Look at Minsk II agreement...It would have preserved Ukraine's territorial integrity and satisfied Russia with the assurance of no NATO membership for Ukraine.

Key points are No. 11 and 12.

Initially, Russia was NOT interested in the annexation of Luhansk and Donetsk region. It  very much wanted these regions to stay within Ukraine for good reason...I hope you guys realized that.