As explained in Machine requirements, CPUs manufactured before 2012 (that is, processors earlier than Intel Ivy Bridge and Xeon E5 v2) do not support the RDRAND instruction. If the Proxmox host runs one of these old CPUs:
- In the Proxmox web interface, select the PKI Hub virtual machine and open the Hardware tab.
- Click Add > RNG Device.
- Set the source to
/dev/urandom - Leave the default rate limit settings.
This configuration exposes /dev/hwrng inside the guest VM, allowing the rngd service to start.
Without either RDRAND support or an RNG device, the installation cannot proceed.