Description of problem:
[Azure] External to LoadBalancer service failed for UDN
Version-Release number of selected component (if applicable):
4.18.0-0.nightly-arm64-2025-02-07-011241

How reproducible:
Alwyas

Steps to Reproduce:

1. Ran auto case, it failed in azure platform.
SDN udn services Author:huirwang-High-76014-Validate LoadBalancer service for UDN pods (Layer3/Layer2)

Checking the post run environment:

% oc get svc -n e2e-test-udn-networking-udn-j95qd
NAME           TYPE           CLUSTER-IP      EXTERNAL-IP     PORT(S)           AGE
test-service   LoadBalancer   172.30.14.134   130.131.176.3   27017:32619/TCP   3m9s

% oc get pods -n e2e-test-udn-networking-udn-j95qd
NAME        READY   STATUS    RESTARTS   AGE
hello-pod   1/1     Running   0          5m16s
% oc exec -n e2e-test-udn-networking-udn-j95qd  hello-pod --  ip a show ovn-udn1
3: ovn-udn1@if38: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1400 qdisc noqueue state UP group default 
    link/ether 0a:58:0a:c8:00:04 brd ff:ff:ff:ff:ff:ff link-netnsid 0
    inet 10.200.0.4/24 brd 10.200.0.255 scope global ovn-udn1
       valid_lft forever preferred_lft forever
    inet6 fe80::858:aff:fec8:4/64 scope link 
       valid_lft forever preferred_lft forever

From pod, the loadbalancer service can be accessed
% oc rsh -n e2e-test-udn-networking-udn-j95qd hello-pod 
~ $ curl 172.30.14.134:27017
Hello OpenShift!
~ $ curl -I 130.131.176.3:27017
HTTP/1.1 200 OK
X-Request-Port: 8080
Date: Fri, 07 Feb 2025 10:03:31 GMT
Content-Length: 17
Content-Type: text/plain; charset=utf-8

but from external (laptop), cannot access it,  just can be pinged.
%  curl -I 130.131.176.3:27017 --connect-timeout 5
curl: (28) Failed to connect to 130.131.176.3 port 27017 after 5004 ms: Timeout was reached

% ping 130.131.176.3
PING 130.131.176.3 (130.131.176.3): 56 data bytes
64 bytes from 130.131.176.3: icmp_seq=0 ttl=105 time=243.855 ms


% oc get svc -n e2e-test-udn-networking-udn-j95qd -o yaml
apiVersion: v1
items:
- apiVersion: v1
  kind: Service
  metadata:
    annotations:
      kubectl.kubernetes.io/last-applied-configuration: |
        {"apiVersion":"v1","kind":"Service","metadata":{"annotations":{},"labels":{"name":"test-service"},"name":"test-service","namespace":"e2e-test-udn-networking-udn-j95qd"},"spec":{"externalTrafficPolicy":"Cluster","internalTrafficPolicy":"Cluster","ipFamilyPolicy":"SingleStack","ports":[{"name":"http","port":27017,"protocol":"TCP","targetPort":8080}],"selector":{"name":"hello-pod"},"type":"LoadBalancer"}}
    creationTimestamp: "2025-02-07T09:58:20Z"
    finalizers:
    - service.kubernetes.io/load-balancer-cleanup
    labels:
      name: test-service
    name: test-service
    namespace: e2e-test-udn-networking-udn-j95qd
    resourceVersion: "46558"
    uid: dff1817d-8915-46ab-b12c-211a6c320dd1
  spec:
    allocateLoadBalancerNodePorts: true
    clusterIP: 172.30.14.134
    clusterIPs:
    - 172.30.14.134
    externalTrafficPolicy: Cluster
    internalTrafficPolicy: Cluster
    ipFamilies:
    - IPv4
    ipFamilyPolicy: SingleStack
    ports:
    - name: http
      nodePort: 32619
      port: 27017
      protocol: TCP
      targetPort: 8080
    selector:
      name: hello-pod
    sessionAffinity: None
    type: LoadBalancer
  status:
    loadBalancer:
      ingress:
      - ip: 130.131.176.3
        ipMode: VIP
kind: List
metadata:
  resourceVersion: ""

2.

3.

Actual results:

Expected results:

Additional info:

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:

• Provide enough information in the bug description that Engineering doesn’t need to read the entire case history.
• Don’t presume that Engineering has access to Salesforce.
• Do presume that Engineering will access attachments through supportshell.
• 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.

• When showing the results from commands, include the entire command in the output.  
• For OCPBUGS in which the issue has been identified, label with “sbr-triaged”
• For OCPBUGS in which the issue has not been identified and needs Engineering help for root cause, label with “sbr-untriaged”
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