I already have the mining infrastructure available so that is not of a concern.
You don't need any mining infrastructure to operate a mining pool, the same way you don't need to operate a pool to run the mining infrastructure.
With that said, there are no plug-and-play pools that can be deployed as a final product, start by looking at open-source projects like
Ckpool, I know that someone recently deployed a pool and had to hire Con Kolivas to make the Ckpool operational.