Hashicorp has a case study with some details of what they use,
> 4 SREs managing Nomad, Consul, and Vault for 11,000+ nodes across 22 clusters, serving 420+ internal developers
> "We have people who are first-time system administrators deploying applications, building containers, maintaining Nomad. There is a guy on our team who worked in the IT help desk for eight years — just today he upgraded an entire cluster himself."