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. Is unable to phosphorylate maltose. ATP + D-glucosamine = ADP + D-glucosamine 6-phosphate + H(+) Binds 2 Mg(2+) ions per subunit. Monomer. Belongs to the actinobacterial glucosamine kinase family.