A luminaire may be carried by a lighting fixture and may have a generally concave elongate-shaped housing defining an optical chamber and an aperture. The luminaire may include a plurality of lighting devices each having a heat sink, a light source, and a magnetic attachment member. The magnetic attachment member may magnetically bind a lighting device to pads proximate to ferromagnetic material in the housing. Light emitted by the light source may enter the optical chamber and pass through the aperture in a generally orthogonal direction in relation to the orientation of the device. Electrical power may be delivered by one or more power supply unit of either an external or an on-board type, and by using either inductive or conductive coupling. Network interfaces may enable communication of control instructions among a multiple controllers located either within a single luminaire or distributed among multiple luminaires.