# Find the root of the tree of services:
system_service = connection.system_service

# Find the virtual machine:
vms_service = system_service.vms_service
vm = vms_service.list(search: 'name=myvm').first

# Find the service that manages the virtual machine:
vm_service = vms_service.vm_service(vm.id)

# Start the virtual machine explicitly indicating the boot devices and order:
vm_service.start(
  vm: {
    os: {
      boot: {
        devices: [
          OvirtSDK4::BootDevice::NETWORK,
          OvirtSDK4::BootDevice::CDROM
        ]
      }
    }
  }
)

# Wait until the virtual machine is up:
loop do
  sleep(5)
  vm = vm_service.get
  break if vm.status == OvirtSDK4::VmStatus::UP
end