In Puttygen, create your key as you would for any other scenario. then, after the key is created, click Conversions, Export ssh.com key. i saved mine as a 3rd file of same name with -alt inthe name (you can of course pick anything).
pick the -alt file as your key file in your centrify DM deployment manager.
(and pre-deploy the keyfile to authorized_keys on all your linux systems)