Description of problem:

Version-Release number of the following components:
rpm -q openshift-ansible
# git log --oneline -1
0e60053 Merge pull request #9670 from openshift/revert-9622-skip-extra-pkg-check

# rpm -q ansible
ansible-2.6.2-1.el7ae.noarch

# ansible --version
ansible 2.6.2
  config file = /root/openshift-ansible/ansible.cfg
  configured module search path = [u'/root/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/lib/python2.7/site-packages/ansible
  executable location = /usr/bin/ansible
  python version = 2.7.5 (default, Jul 16 2018, 19:52:45) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

# yum list installed | grep openshift
atomic-openshift.x86_64         3.11.0-0.16.0.git.0.6bcbde8.el7


How reproducible: Always

Steps to Reproduce:
1. # ansible-playbook -i inv/ openshift-ansible/playbooks/openshift-glusterfs/config.yml -vv
2.
3.

Actual results:
2018-08-20 15:18:20,845 p=15001 u=root |  TASK [openshift_storage_glusterfs : Ensure device mapper modules loaded] *****************************************************
2018-08-20 15:18:20,845 p=15001 u=root |  task path: /root/openshift-ansible/roles/openshift_storage_glusterfs/tasks/kernel_modules.yml:2
2018-08-20 15:18:20,901 p=15001 u=root |  fatal: [ec2-34-219-0-102.us-west-2.compute.amazonaws.com]: FAILED! => {
    "msg": "The conditional check 'inventory_hostname not in groups['glusterfs_registry']' failed. The error was: error while evaluating conditional (inventory_hostname not in groups['glusterfs_registry']): Unable to look up a name or access an attribute in template string ({% if inventory_hostname not in groups['glusterfs_registry'] %} True {% else %} False {% endif %}).\nMake sure your variable name does not contain invalid characters like '-': argument of type 'StrictUndefined' is not iterable\n\nThe error appears to have been in '/root/openshift-ansible/roles/openshift_storage_glusterfs/tasks/kernel_modules.yml': line 2, column 3, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n---\n- name: Ensure device mapper modules loaded\n  ^ here\n"
}


Expected results:

Additional info:
Please attach logs from ansible-playbook with the -vvv flag
Logs will be attached.

Workaround:
Add the following line in the inventory file even though no host is in the group.
[glusterfs_registry]