Could two VMs share the same rack when we talk about spread placement group?
A spread placement group is a group of instances that are each placed on distinct racks, with each rack having its own network and power source.
As noted, if you start or launch an instance in a spread placement group, and there is not enough unique hardware for it, the start/launch will fail. You can repeat the request as resources free up, or new underlying hardware is added.
Why then on 05:34 video, spread placement group image, shows that VM1 and VM3 share the same Rack1?