Comment 13 for bug 1787910

So checked further and found https://review.openstack.org/#/c/565841 to be possible cause. Just to confirm this i hacked nova/virt/ironic/driver a little and overcloud deployment completed.
So i can say that either this patch missed something, or it needs to be fixed at some place(resource_classes are not used correctly as the commit message says).

From logs:- --- No valid Host in overcloud deployment-----
baremetal nodes created using --resource-class baremetal and flavors have resources:CUSTOM_BAREMETAL='1' property

1) Filter RamFilter returned 0 hosts
https://logs.rdoproject.org/openstack-periodic/git.openstack.org/openstack-infra/tripleo-ci/master/legacy-periodic-tripleo-ci-centos-7-ovb-1ctlr_1comp-featureset002-master-upload/9a25ebd/logs/undercloud/var/log/containers/nova/nova-scheduler.log.txt.gz#_2018-08-21_13_27_59_434

2) Hypervisor/Node resource view: name=8c577f07-b040-4b28-9dc0-40e22524a366 free_ram=0MB free_disk=0GB free_vcpus=unknown pci_devices=None
https://logs.rdoproject.org/openstack-periodic/git.openstack.org/openstack-infra/tripleo-ci/master/legacy-periodic-tripleo-ci-centos-7-ovb-1ctlr_1comp-featureset002-master-upload/9a25ebd/logs/undercloud/var/log/containers/nova/nova-compute.log.txt.gz#_2018-08-21_13_23_07_721

phys_ram=0MB used_ram=0MB phys_disk=0GB used_disk=0GB total_vcpus=0 used_vcpus=0 pci_stats=[]
https://logs.rdoproject.org/openstack-periodic/git.openstack.org/openstack-infra/tripleo-ci/master/legacy-periodic-tripleo-ci-centos-7-ovb-1ctlr_1comp-featureset002-master-upload/9a25ebd/logs/undercloud/var/log/containers/nova/nova-compute.log.txt.gz#_2018-08-21_13_23_07_929

Can someone from nova/ironic look at it?