Description of problem:
Scale up nodes failed at task [Apply ignition manifest]

Version-Release number of the following components:
openshift-ansible-4.1.0-201904091404

ansible 2.7.9
  config file = /home/wmeng/openshift/openshift-ansible/ansible.cfg
  configured module search path = ['/home/wmeng/.ansible/plugins/modules', '/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python3.6/site-packages/ansible
  executable location = /usr/local/bin/ansible
  python version = 3.6.6 (default, Mar 29 2019, 00:03:27) [GCC 4.8.5 20150623 (Red Hat 4.8.5-36)]

https://github.com/openshift/openshift-ansible/blob/master/roles/openshift_node/tasks/config.yml#L78

How reproducible:
Always

Steps to Reproduce:
following https://github.com/openshift/openshift-ansible/blob/master/README.md
1. set up OCP4 cluster
2. prepare new_worker vms
3. run scaleup playbook
$ansible-playbook -i inventory/hosts playbooks/scaleup.yml

Actual results:
failed due to host UNREACHABLE

<ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com> SSH: EXEC ssh -o ControlMaster=auto -o ControlPersist=600s -o StrictHostKeyChecking=no -o 'IdentityFile="/home/wmeng/shared-secrets/aws/libra.pem"' -o KbdInteractiveAuthentication=no -o PreferredAuthentications=gssapi-with-mic,gssapi-keyex,hostbased,publickey -o PasswordAuthentication=no -o User=ec2-user -o ConnectTimeout=30 -o ControlPath=/home/wmeng/.ansible/cp/%h-%r -tt ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com '/bin/sh -c '"'"'sudo -H -S -n -u root /bin/sh -c '"'"'"'"'"'"'"'"'echo BECOME-SUCCESS-pwwpajzkopvjdnttsmmyispqpjrskwdv; /usr/bin/python /home/ec2-user/.ansible/tmp/ansible-tmp-1554971512.1921854-243809547831033/async_wrapper.py 339131747332 900 /home/ec2-user/.ansible/tmp/ansible-tmp-1554971512.1921854-243809547831033/AnsiballZ_command.py _'"'"'"'"'"'"'"'"' && sleep 0'"'"''
Escalation succeeded
<ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com> (255, b'{"started": 1, "_ansible_suppress_tmpdir_delete": true, "finished": 0, "results_file": "/root/.ansible_async/339131747332.4000", "ansible_job_id": "339131747332.4000"}\r\n', b'Shared connection to ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com closed.\r\n')
fatal: [ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com]: UNREACHABLE! => {
    "changed": false,
    "msg": "Failed to connect to the host via ssh: Shared connection to ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com closed.",
    "unreachable": true
}

PLAY RECAP ********************************************************************************************************************************************************************************************************
ec2-18-182-49-196.ap-northeast-1.compute.amazonaws.com : ok=18   changed=7    unreachable=1    failed=0   
ec2-54-199-196-17.ap-northeast-1.compute.amazonaws.com : ok=18   changed=7    unreachable=1    failed=0   
ec2-54-95-137-65.ap-northeast-1.compute.amazonaws.com : ok=18   changed=7    unreachable=1    failed=0   
localhost                  : ok=0    changed=0    unreachable=0    failed=0   

Thursday 11 April 2019  04:39:00 -0400 (0:07:08.795)       0:08:59.703 ******** 
=============================================================================== 
openshift_node : Apply ignition manifest ----------------------------------------------------------------------------------------------------------------------------------------------------------------- 428.80s
/home/wmeng/openshift/openshift-ansible/roles/openshift_node/tasks/config.yml:78 ---------------------------------------------------------------------------------------------------------------------------------


Expected results:
ansible playbook complete successfully.