[chef] Chef isn't properly detecting a rackspace cloud server

[< >]

I have created a number of servers in recent weeks using 'knife backspace
server create blah blah'. These have all worked fine, except the last couple i
have created have had sporadic issues where chef doesn't detect that they are
Rackspace cloud serves, and so things like node[:cloud][:private_ips].first or
node[:rackspace][:private_ip] do not work at all. So, two questions:

1. Why does it not properly detect that it's a Rackspace Cloud server, and
2. Is there a way to tell Chef that it's a Rackspace Cloud server so that the
code above works?

Thanks