This is a clone of issue OCPBUGS-38697. The following is the description of the original issue:
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Description of problem: After migrating cluster from SDN to OVN, seeing intermittent failures while accessing service. 

Wed Jul 31 05:28:11 UTC 2024
Wed Jul 31 01:28:11 EDT 2024
Hello OpenShift!


Wed Jul 31 05:28:42 UTC 2024
Wed Jul 31 01:28:42 EDT 2024
curl: (7) Failed to connect to 34.92.142.227 port 27018 after 75006 ms: Couldn't connect to server


Wed Jul 31 05:30:27 UTC 2024
Wed Jul 31 01:30:27 EDT 2024
Hello OpenShift!



Wed Jul 31 05:31:59 UTC 2024
Wed Jul 31 01:31:59 EDT 2024
Hello OpenShift!


Wed Jul 31 05:33:31 UTC 2024
Wed Jul 31 01:33:31 EDT 2024
Hello OpenShift!


Wed Jul 31 05:34:01 UTC 2024
Wed Jul 31 01:34:01 EDT 2024
curl: (52) Empty reply from server


Wed Jul 31 05:38:51 UTC 2024
Wed Jul 31 01:38:51 EDT 2024
Hello OpenShift!

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

$ oc version
Client Version: 4.15.14
Kustomize Version: v5.0.4-0.20230601165947-6ce0bf390ce3
Server Version: 4.15.0-0.nightly-2024-07-29-053620
Kubernetes Version: v1.28.11+add48d0*no* further _formatting_ is done here

How reproducible: 

Steps to Reproduce:

1. Create a 4.14 SDN OSD on GCP cluster

2. Upgrade to 4.15 

3. Scale cluster to 24 nodes

4. Add cluster-density-v2 workload

5. Run migration and let if finish

6. Start seeing errors

Actual results: Intermittent failures accessing service.

Expected results: Live migration should not cause disruption to service.

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”
• Do not set the priority, that is owned by Engineering and will be set when the bug is evaluated
• Note: bugs that do not meet these minimum standards will be closed with label “SDN-Jira-template”
• For guidance on using this template please see
  OCPBUGS Template Training for Networking  components