fs035 jobs are failing in master to deploy the overcloud - "AnsibleUndefinedVariable: 'external_gateway_ip'

[Ronelle Landy]

periodic-tripleo-ci-centos-8-ovb-3ctlr_1comp-featureset035-master jobs are failing when deploying the overcloud. The following error shows up in the ansible log:

2020-10-13 10:26:20,261 p=146820 u=zuul n=ansible | 2020-10-13 10:26:20.260407 | fa163eec-f7c8-d228-d2a7-000000001202 | FATAL | Render network_config from template | overcloud-novacompute-0 | error={"changed": false, "msg": "AnsibleUndefinedVariable: 'external_gateway_ip' is undefined"}

The full logs are below:

https://logserver.rdoproject.org/openstack-periodic-integration-main/opendev.org/openstack/tripleo-ci/master/periodic-tripleo-ci-centos-8-ovb-3ctlr_1comp-featureset035-master/eebbe79/logs/undercloud/home/zuul/ansible.log.txt.gz

https://logserver.rdoproject.org/openstack-periodic-integration-main/opendev.org/openstack/tripleo-ci/master/periodic-tripleo-ci-centos-8-ovb-3ctlr_1comp-featureset035-master/eebbe79/logs/undercloud/home/zuul/overcloud_deploy.log.txt.gz

The test started failing on 10/11:

https://review.rdoproject.org/zuul/builds?job_name=periodic-tripleo-ci-centos-8-ovb-3ctlr_1comp-featureset035-master

Possibly related to:
 https://opendev.org/openstack/tripleo-ansible/commit/010d93b602c295bbafae1bb60b5b6d851799a518

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/757849

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/757849
Committed: https://git.openstack.org/cgit/openstack/tripleo-ansible/commit/?id=dba86a0ab42bb9dec0f78eec41886b983ac24c29
Submitter: Zuul
Branch: master

commit dba86a0ab42bb9dec0f78eec41886b983ac24c29
Author: Rabi Mishra <email address hidden>
Date: Tue Oct 13 17:55:23 2020 +0530

    Use default for external_gateway_ip in multiple_nics_ipv6.j2

    Use 'fe80::1' as the default external gateway for ipv6.
    We earlier had an ipv4 address as the default in nic config
    templates.

    Closes-Bug: #1899627
    Change-Id: Ia9bd8e17134fbdb83ab3fa49d21e0168ec33623a