GhettoVCB should be installed on each vSphere host in your cluster, not on the vCenter server itself. GhettoVCB operates at the host level, leveraging ESXi's capabilities to create backups of your VMs.
Since it directly interacts with the ESXi hosts for backing up VMs, deploying it on each host ensures that you can manage backups across your cluster, regardless of the VMs' specific host allocations, especially in a DRS-enabled cluster where VMs might move between hosts.