Catalyzes the ATP-dependent phosphorylation of D-glucosamine (GlcN) to D-glucosamine 6-phosphate. May be involved in the phosphorylation of acquired extracellular GlcN derived from the hydrolysis of chitosan, i.e., in the incorporation of exogenous GlcN into the bacterial GlcNAc metabolism. To a lesser extent, is also active on glucose, but is unable to phosphorylate maltose, 18 other sugars and several aminoglycoside antibiotics. ATP + D-glucosamine = ADP + D-glucosamine 6-phosphate + H(+) Binds 2 Mg(2+) ions per subunit. Monomer. Belongs to the actinobacterial glucosamine kinase family.