On Sun, Sep 10, 2023 at 4:13 AM Satish Patel satish.txt@gmail.com wrote:
Folks,
I am trying to set an availability zone for OVN because skyline UI has a mandatory requirement to have an availability zone otherwise you are not allowed to create a network from skyline GUI.
for OVN based deployment only option to set AZ is in ovn-cms-options
# ovs-vsctl set open_vswitch . external_ids:ovn-cms-options="enable-chassis-as-gw,availability-zones=az-0"
Question:
- How do I configure in kolla-ansible to override or set ovn-cms-options on only gateway chassis?
- How does AZ work in OVN because OVN is anyway distributed as per documents, What if I just give foobar AZ name to meet Skyline requirement? Is it going to break anything?
Answering 2.
There are two types of availability zones in Neutron: Routers and Networks.
For Routers, ML2/OVN will schedule the gateway router ports onto the nodes belonging to the availability zones provided by the --availability-zone-hint parameter, for example:
$ openstack router create --availability-zone-hint az-0 --availability-zone-hint az-1 router-0
For Networks. Since DHCP is distributed in ML2/OVN as you pointed out we do not care about scheduling DHCP agents (like ML2/OVS). But there are few cases for Network AZ in ML2/OVN that are related to external ports [0], these are ports that live on a different host than the instance to address use cases such as SR-IOV and Baremetal with ML2/OVN.
You can read more ML2/OVN AZs here: https://docs.openstack.org/neutron/latest/admin/ovn/availability_zones.html
[0] https://docs.openstack.org/neutron/latest/admin/ovn/external_ports.html
Cheers, Lucas