Ironic pick the first disk of the server to install the OS image on, this can be a problem for servers that contains more than one disk attached. It would be nice to be able to select which device you want to deploy the image on.
NOTE: This feature should be aligned with the current work to configure RAID in Ironic, because once the RAID is created you should be able to pick the new created device to be the root device for the image deployement.
[UPDATE 1] This is NOT meant to be choosen by the user (as part of a nova boot command for e.g), but operator should be able to update a field in Ironic (maybe node.properties) to point which hard drive should be used to the image to be deployed on.
To be clear, this should be specified by the operator, not by the nova user.