If you want to have vrrp watch the external networking interface
today, the option ha_vrrp_health_check_interval [1] detects a failure
it re-triggers the transitional change - which works if the external
physical interface fails because the ping will fail.
In fact, we've tried to enable it before [2], but then we had to
revert it [3] due to instability issues [4] in previous releases of
OpenStack. Maybe the previous instability issue [4] was caused by
another keepalived issue mentioned in the comment [5], now I have
tested this option again, it works.
This is how neutron allows monitoring southbound network today, so
I would suggest we add this capability into the charm again.
[1] https://docs.openstack.org/ocata/networking-guide/ \
deploy-ovs-ha-vrrp.html#keepalived-vrrp-health-check
[2] https://review.opendev.org/#/c/601533/
[3] https://review.opendev.org/#/c/603347/
[4] https://bugs.launchpad.net/neutron/+bug/1793102
[5] https://bugs.launchpad.net/neutron/+bug/1793102/comments/5
Change-Id: If2947e7640545cb9a48215afb9b2439fdc33c645
Closes-Bug: 1825966