By default, the VMware Cloud Foundation (VCF) 9.0 Installer requires a minimum of 3 ESXi hosts when you select vSAN (OSA or ESA) for storage or 2 ESXi hosts when you choose to use external storage (Fibre Channel VMFS or NFS). When compared to VCF 5.x where vSAN was the only storage option and it required a minimum of 4 ESXi host, this is certainly a welcome change for our users.
With VCF 5.x, it was possible to deploy using just a single ESXi host for the VCF Management Domain and this question has certainly come up a few time since the GA of VCF 9.0 ...
So what happens when you only enter a single ESXi host into the VCF Installer?
As expected, we see a validation error stating that we have not met the minimum number of ESXi hosts ...
However, this is just the default behavior and of course this was something I had looked into early on with VCF Engineering, since this would be an extremely useful capability to allow our users to easily explore VCF 9 using the smallest number of ESXi hosts for lab purposes only, assuming you can meet the Minimal Resources to Deploy VCF 9.0 in a Lab.