Autoscaling was initially available for AppEngine only and the same (or similar) infrastructure is being made available to Compute Engine. Compute Engine had ac

Autoscaling was initially available for AppEngine only and the same (or similar) infrastructure is being made available to Compute Engine. Compute Engine had access to "basic scaling" which was so horribly broken and unreliable that you may as well just set up a static number of instances. The entire scaling infrastructure of AppEngine was horribly broken and unreliable up until a year-and-half or so ago, but they've put a lot of work into fixing that recently and it's in awesome shape now.