It's been a bit of a pain when rolling out new racks in the routed / evpn switch setup as currently Homer only configured vlans on a switch if there are ports (access or trunk) configured as members of those vlans at layer-2.
The issue this causes is that prior to the first host being added to a given vlan the config for that vlan is missing on the switch, and the sre.network.configure-switch-interfaces cookbook does not add them. Instead, when it tries to configure the given vlan on the port connecting the new host we hit an error, and Homer needs to be used instead to add all the required config.
It was previously suggested to configure vlans based on location in advance, but this is somewhat tricky (relying on naming conventions), so I think a simpler way is just to also parse any interfaces starting with "irb." defined in Netbox. In the new design we always have a local IRB int acting as gateway for the per-rack vlans, so this should work good. It should be doable with a small patch to Homer if people are agreed.