In case this is the answer, I found that in nova.conf, under the [libvirt] stanza, images_type can be set to "lvm".  This looks like it may do the trick - using the compute node's LVM to provision and mount a logical volume, for either persistent or ephemeral storage defined in the flavor.

Can anyone validate that this is the right approach according to our needs?

Also, I have read about the LVM device filters - which is important to avoid the host's LVM from seeing the guest's volumes, in case anyone else finds this message.

Thanks!

Eric