Have you checked out Proxmox? 16 large servers in a cluster config could possibly be powerful enough for your needs (Proxmox lets you cluster 16 servers in eac

Have you checked out Proxmox? 16 large servers in a cluster config could possibly be powerful enough for your needs (Proxmox lets you cluster 16 servers in each cluster); if you need more, split up each part of the services into 16-server chunks. EDIT: seems the limit is no longer 16 per cluster https://pve.proxmox.com/wiki/Cluster_Manager https://pve.proxmox.com/wiki/Cluster_Manager