I know how much of a traffic pump HN is, having had a number of pages front-page here during prime time over the years. It isn't that big of a traffic spike at all. It's a much more interesting and interested group than many sources, but a single-core min-scale cloud compute can handle it presuming you aren't doing something silly.

In this case their hosting app has screwed up SSL configs for some of their GeoIP served options.