Disabling FEX port in ACI causes F1209 ethundefined paths

[thebestusername]

I'm wondering if anyone else has seen anything like this or is aware of an open bug for it?  This looks similar to CSCwb49743 but we are on 5.2(3e) and we are seeing this happen on FEX ports so it may not be related to that bug.

To reproduce: 

Fabric > Inventory > Click on Node-1109 > Click on Interface tab > Left click on a FEX port > Click the Disable button.  

API Inspector shows that the following is sent:
method: POST
url: https://<apic>/api/node/mo/uni/fabric/outofsvc/rsoosPath-[topology/pod-1/paths-1109/pathep-[ethundefined/1]].json
payload:{"fabricRsoosPath:"{"attribute":{"tDn":"topology/pod-1/paths-1109/pathep-[ethundefined/1]","lc":"blacklist","status":"created,modified"},"children":[]}}
response: {"totalcount":"0","imdata":[]}

This will create an F1209 fault
Severity: Minor
Cause: configuration-failed
Affected: uni/fabric/outofsvc/rsoosPath-[topology/pod-1/paths-1109/pathep-ethundefined/1]]  
Description: Fault delegate: Configuration failed for node LS1109, Out of Service Fabric Policy default topology/pod-1/paths-1109/pathep-[ethundefined/1] due to invalid path.

The only way I could see to clear this was to use Postman to send the following to:
https://{{apic}}/api/node/mo/uni/fabric/outofsvc.json
{
  "fabricRsOOsPath": {
  "attributes": {
       "tDn": "topology/pod-1/paths-1109/pathep-[ethundefined/1]",
       "status": "deleted"
   },
       "children": []
   }
}

The problem does not occur if we go to Fabric > Inventory > expand Node-1109 > Expand Interfaces > Expand Physical Interfaces > Right Click a FEX port > Click Disable.  When you disable a FEX port this way, here is what the API Inspector shows:

API Inspector shows that the following is sent:
method: POST
url: https://<apic>/api/node/mo/uni/fabric/outofsvc.json
payload:{"fabricRsoosPath:"{"attribute":{"tDn":"topology/pod-1/paths-1109/extpaths-109/pathep-[eth1/1]",lc":"blacklist"},"children":[]}}
response: {"totalcount":"0","imdata":[]}

[Tarakesh Jetti]

Hi, 

This Bug is only related to 4.2(7f), doesn't see the same bug on Version 5.2(3e).

Bug Search Tool: You can also use bug search tool for any clarification.

https://bst.cisco.com/bugsearch

Explanation :This fault occurs when an out-of-service policy is incorrectly configured.

Recommended Action:  If you see this fault, take the following actions: 

Step 1 Look at the configuration for issues.

Step 2 For invalid-path, confirm that the specified interface is correct .

Step 3 For further details, refer to the documentation for fabric:PathIssues .

Step 4 Verify the fabric selector configuration is correct and complete.

Step 5 If the above action did not resolve the issue, create a tech-support file and contact Cisco TAC.

“You can also learn more about Cisco ACI through our live Ask the Experts (ATXs) session. Check out Cisco ACI ATXs Resources [https://community.cisco.com/t5/data-center-and-cloud-knowledge/cisco-aci-ask-the-experts-resources/ta-p/4394491] to view the latest schedule for upcoming sessions, as well as the useful references, e.g. online guides, FAQs.”

Should you have any question/concern, please feel free to reach out to me.

Thanks and regards,

Tarakesh Jetti

CX - Customer Success Specialist

[thebestusername]

Could you please provide the bug ID?

[Tarakesh Jetti]

Hi, 

It is the same you mentioned -CSCwb49743 - Which is for version 4.2(7f)

https://bst.cisco.com/bugsearch/bug/CSCwb49743.

As per bug search tool, i don't see same bug with version  5.2(3e).

For the Fault -F1209, you can follow the steps(1-5) as  mentioned above or open a TAC case to know more about this Fault in Version 5.2(3e).

“You can also learn more about Cisco ACI through our live Ask the Experts (ATXs) session. Check out Cisco ACI ATXs Resources [https://community.cisco.com/t5/data-center-and-cloud-knowledge/cisco-aci-ask-the-experts-resources/ta-p/4394491] to view the latest schedule for upcoming sessions, as well as the useful references, e.g. online guides, FAQs.”

Should you have any question/concern, please feel free to reach out to me.

Thanks and regards,

Tarakesh Jetti

CX - Customer Success Specialist

[thebestusername · Accepted solution]

I ended up opening a TAC case and this turned out to be a new bug:  CSCwc88854 - F1209 Fault Generated When Disabling FEX Interface From APIC GUI.   From the bug report: "Issue is seen in all FEX models connected to ACI switches running versions up to 5.2(5c)."

[MrSmileyMan]

What is the solution once this bug is hit? Do I need to re-enable the port, then disable it in the correct fashion to clear the bug, or should some other method be followed to clear it?

[thebestusername]

The only way I could see to clear this was via the REST API.  Also, the bug report says it is fixed in 5.2(7f) so if you upgrade to that release or newer then that might resolve it. But it also seems likely that upgrading may just prevent future new occurrences without clearing your current fault.

To clear the fault, I used Postman to send the following to:
https://{{apic}}/api/node/mo/uni/fabric/outofsvc.json
{
  "fabricRsOOsPath": {
  "attributes": {
       "tDn": "topology/pod-1/paths-1109/pathep-[ethundefined/1]",
       "status": "deleted"
   },
       "children": []
   }
}

You would need to first login via postman and you would need to update the tDn shown above to match what you are seeing in your environment.