undercloud - IPv6 - router created by undercloud conflict with infrastructure router

[Harald Jensås]

---- When ----
Router is created for IPv6 provsioning network to quote code[1] comment:
"""
  # If the subnet is IPv6 we need to start a router so that router
  # advertisments are sent out for stateless IP addressing to work.
"""

---- Then ----
The router created using the subnet_id will automatically select the IP address configured as the subnets gateway when the router interface is added. This will cause a conflict when there is an actual router in the infrastructure.

One solution is to first create a port, and then attach that to the router.
But is this router really neccecary? Would'nt the router in the infrastructure be responsible for doing the router advertisements?

NOTE:
  The code[1] is not idempotent, it will try to re-create the
  router on each undercloud install re-run.
  This should be fixed as well.

[1] https://github.com/openstack/tripleo-heat-templates/blob/master/extraconfig/post_deploy/undercloud_ctlplane_network.py#L178-L184

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.opendev.org/685030

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.opendev.org/685030
Committed: https://git.openstack.org/cgit/openstack/tripleo-heat-templates/commit/?id=3bbd48216a181e1955a582e0b05c4ee265ab3c28
Submitter: Zuul
Branch: master

commit 3bbd48216a181e1955a582e0b05c4ee265ab3c28
Author: Harald Jensås <email address hidden>
Date: Wed Sep 25 17:29:07 2019 +0200

    Undercloud ctplane router for IPv6 RA's idempotent

    Check if the router exists before creating it. The undercloud
    re-install fail's when using IPv6 provisioning network since
    the router already exists.

    Also, don't create the router if routed networks is enabled.
    In this case the router in the infrastructure should handle
    router advertisements.

    Change-Id: I5bc0a88bbb7912bb10693ce393ac89365f29a940
    Closes-Bug: #1844767

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/tripleo-heat-templates 11.3.0 release.