Modular data center

An apparatus, comprising:

• a rack assembly comprising a plurality of racks coupled to one another, wherein:
• respective racks among the plurality of racks are configured to hold a plurality of rack-mounted computing devices arrayed in a first direction;
• the plurality of racks are arrayed in one or more directions orthogonal to the first direction for respective racks, with respective racks positioned side-by-side;
• a rack-assembly enclosure, wherein:
• the rack-assembly enclosure is coupled to the rack assembly with:
• at least one degree of freedom of relative movement between the rack-assembly enclosure and the rack assembly, and
• fewer than three degrees of freedom of relative movement between the rack-assembly enclosure and the rack assembly;
• the rack-assembly enclosure comprises a barrier configured to block access to an inaccessible subset of the plurality of racks;
• the rack-assembly enclosure comprises an opening in the barrier configured to permit access to at least part of an accessible subset of the plurality of racks, the accessible subset and the inaccessible subsets being disjoint sets;
• the rack assembly and rack-assembly enclosure are configured to determine which of the plurality of racks are in the inaccessible subset and which of the plurality of racks are in the accessible subset responsive to the at least one degree of freedom of relative movement between the rack-assembly enclosure and the rack assembly, such that relative movement of the rack assembly and rack-assembly enclosure selectively provides physical access to a technician to different rack unit portions of the rack assembly;
• and
• an actuator mechanically coupled to the rack assembly or the rack-assembly enclosure, the actuator being configured to actuate relative movement between the rack assembly and the rack-assembly enclosure in at least one of the one or more degrees of freedom.