Description of problem:

My Customer is reporting the following:

"we don't always have an oo_master group when we are running the plays, playbooks/init/cluster_facts.yml shouldn't error out."

We suspect the new 'Gather master facts'  task  should have a check for the existence of the oo_masters group. 

https://github.com/openshift/openshift-ansible/compare/openshift-ansible-3.11.317-1...openshift-ansible-3.11.318-1#diff-f7299f83c4344765f127597a90ab3ddcbcd76b9bbbaf9ce095cc1644d4f01d0a

Without it I get this error when building a base image for a node : 

[0;32m    amazon-ebs: fatal: [xxx.xxx.xxx.xxx]: FAILED! => {"msg": "The conditional check 'inventory_hostname in groups['oo_masters']' failed. The error was: error while evaluating conditional (inventory_hostname in groups['oo_masters']): Unable to look up a name or access an attribute in template string ({% if inventory_hostname in groups['oo_masters'] %} True {% else %} False {% endif %}).\nMake sure your variable name does not contain invalid characters like '-': argument of type 'AnsibleUndefined' is not iterable\n\nThe error appears to be in '/home/jenkins_slave/openshift-ansible/playbooks/init/cluster_facts.yml': line 42, column 5, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n  - name: Gather Master facts\n    ^ here\n"}[0m

There's a step earlier in the same play that looks like it checks if a group exists at all, Gather Master facts maybe needs a when condition like this one? 

  # oo_first_master group might not be present due to provisioning plays
  # for existing clusters, openshift_portal_net will be force-set by
  # basic_facts.yml from value in existing master configs.
  - name: set_fact openshift_portal_net if present on masters
    set_fact:
      openshift_portal_net: "{{ hostvars[groups.oo_first_master.0].openshift_portal_net }}"
    when:
    - "'oo_first_master' in groups"
    - "groups.oo_first_master | length > 0"
    - "'openshift_portal_net' in hostvars[groups.oo_first_master.0]"


Version-Release number of selected component (if applicable):
OCP 3.11.318

How reproducible:
100%

Steps to Reproduce:
1.
2.
3.

Actual results:

The play errors with:

[0;32m    amazon-ebs: fatal: [xxx.xxx.xxx.xxx]: FAILED! => {"msg": "The conditional check 'inventory_hostname in groups['oo_masters']' failed. The error was: error while evaluating conditional (inventory_hostname in groups['oo_masters']): Unable to look up a name or access an attribute in template string ({% if inventory_hostname in groups['oo_masters'] %} True {% else %} False {% endif %}).\nMake sure your variable name does not contain invalid characters like '-': argument of type 'AnsibleUndefined' is not iterable\n\nThe error appears to be in '/home/jenkins_slave/openshift-ansible/playbooks/init/cluster_facts.yml': line 42, column 5, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n  - name: Gather Master facts\n    ^ here\n"}[0m

Expected results:
Complete without errors


Additional info: