Description of problem: [BGP EIP L3 CUDN LGW mode]  access external agnhost service failed from pod that is not using egressIP but is created in same namespace with egressIP pods 

Version-Release number of selected component (if applicable):

How reproducible:

Steps to Reproduce:

1. Label egress node, 

2. create labelled UDN namespace, label the namespace to match namespaceSelector of egressIP object that will be created in step 5

#oc get ns e2e-test-udn-networking-38t25mij-cjw7b --show-labels | grep org=
e2e-test-udn-networking-38t25mij-cjw7b   Active   87s   cudn-bgp=cudn-network-f63p6zz0,k8s.ovn.org/primary-user-defined-network=null,kubernetes.io/metadata.name=e2e-test-udn-networking-38t25mij-cjw7b,org=qe,pod-security.kubernetes.io/audit-version=latest,pod-security.kubernetes.io/audit=restricted,pod-security.kubernetes.io/enforce-version=latest,pod-security.kubernetes.io/enforce=restricted,pod-security.kubernetes.io/warn-version=latest,pod-security.kubernetes.io/warn=restricted

3. create L3 CUDN, label the L3 CUDN properly to match the networkSelector of CUDN RA that will be created in step 4

4. create a CUDN RA that has both EgressIP and PodNetwork in advertisements spec, use {} for nodeSelector

#oc get ra ra-cudn -oyaml
apiVersion: k8s.ovn.org/v1
kind: RouteAdvertisements
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"k8s.ovn.org/v1","kind":"RouteAdvertisements","metadata":{"annotations":{},"name":"ra-cudn"},"spec":{"advertisements":["PodNetwork","EgressIP"],"frrConfigurationSelector":{},"networkSelectors":[{"clusterUserDefinedNetworkSelector":{"networkSelector":{"matchLabels":

}},"networkSelectionType":"ClusterUserDefinedNetworks"}],"nodeSelector":{}}}
  creationTimestamp: "2025-05-28T17:36:20Z"
  generation: 1
  name: ra-cudn
  resourceVersion: "898903"
  uid: 1858ff97-d5c7-4f65-942e-324dfc3442c1
spec:
  advertisements:
  - PodNetwork
  - EgressIP
  frrConfigurationSelector: {}
  networkSelectors:
  - clusterUserDefinedNetworkSelector:
      networkSelector:
        matchLabels:
          app: udn
    networkSelectionType: ClusterUserDefinedNetworks
  nodeSelector: {}
status:
  conditions:
  - lastTransitionTime: "2025-05-28T17:36:42Z"
    message: ovn-kubernetes cluster-manager validated the resource and requested the
      necessary configuration changes
    observedGeneration: 1
    reason: Accepted
    status: "True"
    type: Accepted
  status: Accepted

5. Create an egressIP object with namespaceSelector matching label of the UDN namespace

#oc get egressip -oyaml
apiVersion: v1
items:

• apiVersion: k8s.ovn.org/v1
    kind: EgressIP
    metadata:
      annotations:
        k8s.ovn.org/egressip-mark: "50001"
      creationTimestamp: "2025-05-28T18:06:04Z"
      generation: 2
      name: egressip-79715
      resourceVersion: "908165"
      uid: e660da13-3893-400d-8f0d-9fcc1e6893be
    spec:
      egressIPs:
      - 192.168.111.96
      namespaceSelector:
        matchLabels:
          org: qe
      podSelector:
        matchLabels:
          color: pink
    status:
      items:
      - egressIP: 192.168.111.96
        node: worker-0
  kind: List
  metadata:
    resourceVersion: ""

6. Create two egressIP pods local and remote to egress node, their label should match the podSelector of egressIP object created in step 5

7. Create a third test pod without podSelector label, so it is not using egressIP

#oc -n e2e-test-udn-networking-38t25mij-cjw7b get pod --show-labels
NAME                                                       READY   STATUS    RESTARTS   AGE   LABELS
hello-pod-non-eip-e2e-test-udn-networking-38t25mij-cjw7b   1/1     Running   0          20s   name=hello-pod
hello-pod0-eip-e2e-test-udn-networking-38t25mij-cjw7b     1/1     Running   0          85s   color=pink,name=hello-pod
hello-pod1-eip-e2e-test-udn-networking-38t25mij-cjw7b      1/1     Running   0          73s   color=pink,name=hello-pod

#oc get pod -owide
NAME                                                       READY   STATUS    RESTARTS   AGE     IP            NODE       NOMINATED NODE   READINESS GATES
hello-pod-non-eip-e2e-test-udn-networking-38t25mij-cjw7b   1/1     Running   0          65s     10.131.0.21   worker-0   <none>           <none>
hello-pod0-eip-e2e-test-udn-networking-38t25mij-cjw7b      1/1     Running   0          2m10s   10.131.0.14   worker-0   <none>           <none>
hello-pod1-eip-e2e-test-udn-networking-38t25mij-cjw7b      1/1     Running   0          118s    10.129.2.8    worker-2   <none>           <none>

8.  from these pods, curl external agnhost service

#oc rsh hello-pod0-eip-e2e-test-udn-networking-38t25mij-cjw7b
~ $ curl 172.20.0.100:8000 --connect-timeout 2 -I
HTTP/1.1 200 OK
Date: Wed, 28 May 2025 17:40:57 GMT
Content-Length: 63
Content-Type: text/plain; charset=utf-8

~ $ exit
#oc rsh hello-pod1-eip-e2e-test-udn-networking-38t25mij-cjw7b
~ $ curl 172.20.0.100:8000 --connect-timeout 2 -I
HTTP/1.1 200 OK
Date: Wed, 28 May 2025 17:41:17 GMT
Content-Length: 63
Content-Type: text/plain; charset=utf-8

#oc rsh hello-pod-non-eip-e2e-test-udn-networking-38t25mij-cjw7b
~ $  curl 172.20.0.100:8000 --connect-timeout 2 -I
curl: (28) Connection timeout after 2002 ms
~ $ command terminated with exit code 137

Actual results: curl external agnhost service from third pod that is not using egressIP failed, although curl external agnhost service from egressIP pods all succeeded

Expected results: curl external agnhost service from all pods (egressIP pods or non-egressIP pod) should all succeed

Additional info:  same test passed for SGW mode

Please fill in the following template while reporting a bug and provide as much relevant information as possible. Doing so will give us the best chance to find a prompt resolution.

Affected Platforms:

Is it an

1. internal CI failure
2. customer issue / SD
3. internal RedHat testing failure

If it is an internal RedHat testing failure:

• Please share a kubeconfig or creds to a live cluster for the assignee to debug/troubleshoot along with reproducer steps (specially if it's a telco use case like ICNI, secondary bridges or BM+kubevirt).

If it is a CI failure:

• Did it happen in different CI lanes? If so please provide links to multiple failures with the same error instance
• Did it happen in both sdn and ovn jobs? If so please provide links to multiple failures with the same error instance
• Did it happen in other platforms (e.g. aws, azure, gcp, baremetal etc) ? If so please provide links to multiple failures with the same error instance
• When did the failure start happening? Please provide the UTC timestamp of the networking outage window from a sample failure run
• If it's a connectivity issue,
• What is the srcNode, srcIP and srcNamespace and srcPodName?
• What is the dstNode, dstIP and dstNamespace and dstPodName?
• What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)

If it is a customer / SD issue:

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• Describe what each relevant attachment is intended to demonstrate (failed pods, log errors, OVS issues, etc).
• Referring to the attached must-gather, sosreport or other attachment, please provide the following details:
  • If the issue is in a customer namespace then provide a namespace inspect.
  • If it is a connectivity issue:
    • What is the srcNode, srcNamespace, srcPodName and srcPodIP?
    • What is the dstNode, dstNamespace, dstPodName and dstPodIP?
    • What is the traffic path? (examples: pod2pod? pod2external?, pod2svc? pod2Node? etc)
    • Please provide the UTC timestamp networking outage window from must-gather
    • Please provide tcpdump pcaps taken during the outage filtered based on the above provided src/dst IPs
  • If it is not a connectivity issue:
    • Describe the steps taken so far to analyze the logs from networking components (cluster-network-operator, OVNK, SDN, openvswitch, ovs-configure etc) and the actual component where the issue was seen based on the attached must-gather. Please attach snippets of relevant logs around the window when problem has happened if any.

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