Hi guys, I faced similar issues when using ansible last 5/24 Friday, my comments:

• Build info: 20190521T132734Z

First try, steps I followed: 
- Installed Stx and changed the wrsroot password.
- Followed "Ansible bootstrap install steps"
   ip address add 192.168.90.3/24 dev eno1
   ip link set up dev eno1
   route add default gw 192.168.90.1 eno1
- Ping successfully to docker registry 192.168.90.60
- Create /home/wrsroot/localhost.yml

-------------localhost.yml--------------------------
# Mandatory
system_mode: duplex

# Optional
external_oam_subnet: 192.168.90.0/24
external_oam_gateway_address: 192.168.90.1
external_oam_floating_address: 192.168.90.240
external_oam_node_0_address: 192.168.90.106
external_oam_node_1_address: 192.168.90.105
management_subnet: 10.10.62.0/24
docker_registries:
  - 192.168.90.60
dns_servers:
  - 192.168.90.60
admin_password: St4rlingX*
ansible_become_pass: St4rlingX*

-------------localhost.yml--------------------------

- Ran "ansible-playbook /usr/share/ansible/stx-ansible/playbooks/bootstrap/bootstrap.yml". Please check attached "Ansible playbook command output 1" file where is displaying following warning.
   [WARNING]: Module remote_tmp /tmp/.ansible-root/tmp did not exist and was
   created with a mode of 0700, this may cause issues when running as another
   user. To avoid this, create the remote_tmp dir with the correct permissions
   manually

- I did create /tmp/.ansible-root/tmp folders and did 'chmod 777' to all of them.

- I ran it for a second time and for some reason it seems the "localhost.yml" placed on HOME it was not taken since is pingin to 8.8.8.8 instead of my "192.168.90.60" docker registy ip. Please check attached "Ansible bootstrap install pings 8.8.8.8" file showing below error:

  TASK [validate-config : Fail if DNS Server is unreachable]
  **********************************************************************************************************
   fatal: [localhost]: FAILED! => {"changed": false, "msg": "The provided DNS Server 8.8.8.8 is unreachable."}

- Erich helped me out to do some troubleshooting and we added the "is_securr_registry" flag to the "localhost.yml" and ran it again, [it was like the fifth time, do not remember well the numbre after several  tries]

Please look at the "Ansible bootstrap install output 5" for details. 
Please see final "localhost.yml" used.

-------------localhost.yml--------------------------
# Mandatory
system_mode: duplex

# Optional
external_oam_subnet: 192.168.90.0/24
external_oam_gateway_address: 192.168.90.1
external_oam_floating_address: 192.168.90.240
external_oam_node_0_address: 192.168.90.106
external_oam_node_1_address: 192.168.90.105
management_subnet: 10.10.62.0/24
docker_registries:
  - 192.168.90.60
is_secure_registry: False
dns_servers:
  - 192.168.90.60
admin_password: St4rlingX*
ansible_become_pass: St4rlingX*
-------------localhost.yml--------------------------

- The wiki does not have instructions for local registry and it would be beneficial for the community to be updated it --> https://wiki.openstack.org/wiki/StarlingX/Containers/InstallationOnAIODX#Bootstrap_the_controller

-After all of this my assumption is that after you try the "ansible-playbook" command and it fails for some reason, you cannot re-run it even if you change the localhost.yml file.