This is tracking the upstream effort needed to deliver the feature request described below.

What's the feature?

If a router/switch has dynamic-routing=true (existing option) and (new option) dynamic-routing-advertise-per-object=true (default=false) then:

FOR logical routers with dynamic-routing-advertise set:

• if dynamic-routing-redistribute ~ connected-as-host
  • advertise LSP IPs if LSP.option.dynamic-routing-advertise=true
  • advertise LRP IPs if LRP.option.dynamic-routing-advertise=true
• if dynamic-routing-redistribute ~ nat/lb
  • advertise NAT/LB IPs if NAT/LB.option.dynamic-routing-advertise=true
• if dynamic-routing-redistribute ~ static
  • advertise static route prefix if Static_Route.option.dynamic-routing-advertise=true

FOR EVPN logical switches with dynamic-routing-advertise set:

• if dynamic-routing-redistribute ~ fdb/ip
  • advertise LSP IPs/MAC if LSP.option.dynamic-routing-advertise=true

Why is it needed?

Today, if dynamic-routing-redistribute=connected-as-host/lb/nat/static/fdb/ip is set for a logical router (port) then OVN indiscriminately advertises the IPs (or prefixes) of all the matching records (NATs, LB VIPs, LSP IPs/MACs, LRP IPs/MACs, static route prefixes).

However, some CMS might want more granularity and selectively configure which of the records should be advertised.  For example, if dynamic-routing-redistribute=nat and the logical router has three NAT entries defined:

1. NAT1-public-IP -> NAT1-logical-IP
2. NAT2-public-IP -> NAT2-logical-IP
3. NAT3-public-IP -> NAT3-logical-IP

The CMS might want to only advertise NAT1-public-IP and NAT3-public-IP.  Without an explicit, per NAT option, this wouldn't be possible.

As we don't want to change the current default behavior, this feature needs to be opt-in, globally enabled per router through the new LR.options:dynamic-routing-advertise-per-object=true|false (default false) option.

Who will benefit? 

ovn-kubernetes transitioning to use OVN's native BGP support.  Potentially neutron-ovn too.