[Feature Request] Allow underlay external subnet to custom VPC without making default external network mandatory

[abasitt]

Description

I am following this guide to attach a unique external underlay subnet to a custom VPC. But seems like it is only possible to make it work if we have default external subnet defined.
In the custom VPC, there is an option to add extraExternalSubnets but no option to exclude default external network.

I think we should have option.

• No dependency on default external network for custom vpc. User should be able to define and attach external underlay network to custom VPC without modifying kube-controller and cni to add default external network first.
• Able to add extraExternalSubnets and can exclude default external network.

My use-case is assign different vlans to different VPC as external networks and I want to isolate. I was able to workaround this by creating a dummy vlan as default external network.

E.g.
My goal is to add a custom externalsubnet to a custom vpc101.

If i make enablexternal:false and just leave addexternalsubnet, nothing gets added.

apiVersion: kubeovn.io/v1
kind: Vpc
metadata:
  name: vpc101
spec:
  namespaces:
  - vpc101
  enableExternal: false # want to exclude default external network external204
  extraExternalSubnets: # want to include custom external network unique to this vpc
  - external
---
kubectl ko nbctl show vpc101
router 2f8ddb7c-bf8f-4193-b7da-6f87d1891643 (vpc101)
    port vpc101-vpc101-subnet1
        mac: "7a:e8:95:37:bd:28"
        networks: ["192.168.0.1/24"]

If I change enableexternal:true and addextraexternal subnet will add both default and additional extra subnet.

apiVersion: kubeovn.io/v1
kind: Vpc
metadata:
  name: vpc101
spec:
  namespaces:
  - vpc101
  enableExternal: true
  extraExternalSubnets:
  - external
---
kubectl ko nbctl show vpc101
router 2f8ddb7c-bf8f-4193-b7da-6f87d1891643 (vpc101)
    port vpc101-external204
        mac: "0e:0e:8a:00:c2:c9"
        networks: ["10.5.204.103/24"]
        gateway chassis: [0fb6cd0a-9801-4870-9557-067070358015]
    port vpc101-vpc101-subnet1
        mac: "7a:e8:95:37:bd:28"
        networks: ["192.168.0.1/24"]
    port vpc101-external
        mac: "86:e9:20:8d:18:4d"
        networks: ["10.9.129.152/16"]
        gateway chassis: [0fb6cd0a-9801-4870-9557-067070358015]

Who will benefit from this feature?

No response

Anything else?

No response

[bobz965]

Thanks four you info, I will try to make it.