Devices, apparatuses, and systems for thermal management in networking and computing systems are provided. An example in-rack thermal management system includes a cooling distribution unit (CDU) that includes a housing that defines a fluid inlet and a fluid outlet, thermal management components supported by the housing, and direct mechanical connections coupled with the fluid inlet and the fluid outlet. The in-rack thermal management system includes a fluid distribution system that includes a primary fluid channel directly coupled with the direct mechanical connection of the fluid inlet, and a secondary fluid channel directly coupled with the direct mechanical connection of the fluid outlet. In operation, the thermal management components dissipate heat of a fluid received by the CDU via the fluid inlet. The direct mechanical connections directly interface with the fluid distribution system to provide fluid communication between the CDU and the fluid distribution system to maximize dimensions of the housing.