Currently for installing physical machines one can use
ai-installhost command in order to provide a custom kickstart file. When creating an instance using Bare Metal Service you can provide only an OpenStack Image, which means all the custom configuration has to be done from inside of the image.
When using Ironic,
ai-installhost is not available right away. You need to wait for Puppet to run at least once in order to use the tool.
In the future we are going to provide a set of default templates for various RAID configurations.