- Spin up hundreds or thousands of VM's dynamically without much intervention from netops. These VM's would exist across many hypervisors and be provisioned dynamically.
- Allow inbound traffic to the guest VM's from networks outside the hypervisor.
The built-in VirtualBox networking options really wouldn't fit the bill. Here's why:
- Bridged networking would require a lot of prior planning and work from netops. Would all the hypervisors be in the right VLAN to get the various subnets required? Some of the hypervisors might reside in smaller existing networks that would be /22-/24. Nope, too much work to support that across all of our locations.
- Internal networks can only communicate with VM's residing on the same hypervisor. External access is a must.
- Host-only networks only allow the VM to communicate with the hypervisor and other VM's. Similar to internal but not the outside world.
- NAT networking would be a huge pain to map all of the inbound ports to VM ports. Reducing work was a goal here.