Just throwing this in here as another thing to consider - instruction set. From a quick check (so I’m happy to be told I’m wrong) the Celeron & Pentium options don’t support AVX. That means some stuff - and I’m giving a hard stare at MongoDB here, but there will be others - is not going to run, or at best you’re going to be either stuck with old versions or recompiling yourself from source.

(I don’t know if any of your apps require Mongo or AVX, but I was bitten by this in the past and it was one of the main reasons I eventually upgraded one of my small clusters.)