I worked for a SaaS that ran a hybrid infra, partially on metal. Each rack had N blade enclosures, which together made up a logical isolated unit, with each bla

I worked for a SaaS that ran a hybrid infra, partially on metal. Each rack had N blade enclosures, which together made up a logical isolated unit, with each blade running something. New blades would get provisioned automatically, then Terraform and Puppet handled their configuration. I don’t remember utilization exactly, but I think most of the blades were reasonably committed. That said, when I left they were moving from a hybrid model to entire cloud, so apparently the cost:flexibility ratio wasn’t to peoples’ liking.