The attached inventory is missing node groups.

Please update the hosts section to the following and retest...

################################################################################
# cluster specific settings maybe be placed here

[masters]

[masters:vars]
openshift_node_group_name=node-config-master

[etcd]

[etcd:children]
masters

[infra]

[infra:vars]
openshift_node_group_name=node-config-infra

[nodes]

[nodes:children]
masters

[nodes:vars]
openshift_node_group_name=node-config-compute

I'm finally confirming this...

Looks like node cloud-init user-data contains a wrong openshift_node_config_name value
# cat /var/lib/cloud/instances/i-0519dfea2d9a8068f/user-data.txt
#cloud-config

write_files:
- path: /root/openshift_bootstrap/openshift_settings.yaml
  owner: 'root:root'
  permissions: '0640'
  content: |
    openshift_node_config_name: node-config-master

runcmd:
- [ ansible-playbook, /root/openshift_bootstrap/bootstrap.yml]


bootstrap file content is also incorrect...
# cat openshift_bootstrap/openshift_settings.yaml
openshift_node_config_name: node-config-master

https://github.com/openshift/openshift-ansible/pull/9828

pull/9828 has /lgtm.  The robot should merge the pull today.

Please retest when pull is merged.

*** Bug 1622788 has been marked as a duplicate of this bug. ***

Fixed at: openshift-ansible-3.11.0-0.25.0-34-g04f8519

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:2652