In February 2015, the volunteer went to the front (before that he went to the military several times to mobilize him). Sergeant, Senior Investigator, Radiotelegrafist of the Intelligence Platoon of the 1st Mechanized Battalion of the 93nd Detached Mechanized Brigade.

Killed on June 21, 2015 in the area of ​​settlements of Avdeyivka - Optin, near Donetsk airport. After duty Vitali went to rest, but it turned out that the tank, shooting, interrupted the wire, with which the soldiers maintained the connection. Sergeant Kozak, along with soldier Igor Patuk, went looking for a break. When still going on trenches, then nothing, and then had to step on the wire itself. Just at this time, the enemy sniper got into Vitali, the ball hit the carotid artery, he died on the spot.