You can be secretive all you want, but it's extremely difficult to hide massive heat exchanging systems and/or generators from aerial/space photography. Particularly at the scale of an AWS-like datacenter.
Building a fully camouflaged datacenter could be done at much greater cost, but you still can't hide its thermal emissions from infrared. Basically every watt hour used in a datacenter environment turns into waste heat ultimately rejected into the atmosphere (except for the 0.000000001% that leaves the facility as photons down a fiber), so if you have N megawatts of waste heat from a rectangular shaped building located on a 300 x 400 meter sized plot of land, it's going to stand out.
Building a fully camouflaged datacenter could be done at much greater cost, but you still can't hide its thermal emissions from infrared. Basically every watt hour used in a datacenter environment turns into waste heat ultimately rejected into the atmosphere (except for the 0.000000001% that leaves the facility as photons down a fiber), so if you have N megawatts of waste heat from a rectangular shaped building located on a 300 x 400 meter sized plot of land, it's going to stand out.