ACI EPG's in a freeze state

[DuaBell]

Hi Everyone,

Below is an error message that i detected on the ACI fabric and was not very descriptive to investigate on which EPG's are in the freeze state.

I had a look on the internet and could not find much information, besides a 'show command' to check the EPG's (no name was provided in the output) on the spine switches.

Below is the error message:

F3696

Severity:

major

Last Transition:

2021-10-09T01:48:27.348+02:00

Lifecycle:

Raised

Affected Object:

topology/pod-1/node-301/sys/coop/inst/dom-overlay-1

Description:

7 EPs are in freeze state.

Type:

Operational

Cause:

coop-ep-dampening

Change Set:

noOfDampenedEPs (New: 7)

Created:

2021-10-09T01:46:00.778+02:00

Code:

F3696

Number of Occurrences:

1

Original Severity:

major

Previous Severity:

major

Highest Severity:

major

Output from the show command:

spine303# show coop internal info repo ep dampening

EP bd vnid : 16449434
EP mac : 00:1E:67:AC:04:81
num of ipv4 addresses : 1
num of ipv6 addresses : 0
Damp penalty : 4359
Damp status : FREEZE

------------------------------------------
EP bd vnid : 16154559
EP mac : 00:50:56:B1:2E:39
num of ipv4 addresses : 1
num of ipv6 addresses : 0
Damp penalty : 10300
Damp status : FREEZE

------------------------------------------
EP bd vnid : 16449434
EP mac : 00:50:56:B1:6F:7D
num of ipv4 addresses : 2
num of ipv6 addresses : 0
Damp penalty : 13056
Damp status : FREEZE

------------------------------------------
EP bd vnid : 16449434
EP mac : 00:50:56:B1:50:12
num of ipv4 addresses : 1
num of ipv6 addresses : 0
Damp penalty : 4390
Damp status : FREEZE

------------------------------------------
EP bd vnid : 16449434
EP mac : 00:50:56:99:4E:44
num of ipv4 addresses : 1
num of ipv6 addresses : 0
Damp penalty : 5309
Damp status : FREEZE

------------------------------------------

May anyone please advise as to why the EPG's freeze and how can i check and confirm which EPG's are in the freeze state?

[Sergiu.Daniluk · Accepted solution]

Most likely the EPs were flapping. Check what other faults you have related to those EPs. You should resolve that first.

Stay safe,

Sergiu

[DuaBell]

Hi Sergiu,

Thanks for your response.

I had a look and it is related to an issue that we are busy resolving.

My only concern was the error message; stating that the EP's are in a freeze state.

Is there any impact on the endpoints?

[Sergiu.Daniluk]

The effect of EP dampening is to make all leafs to ignore any updates coming from the freezed endpointes. This way, no additional COOP updates will be sent to spines and will prevent problems in COOP and/or control plane.

Basically, if there are changes to the EPs (different interface, different MAC_IP mapping) the fabric will not be informed about it, and it will keep the previous known state.

If this will create a problem or not in the fabric, it all depends on what is generating the EPs to freeze.

Stay safe,

Sergiu

[Robert Burns · Accepted solution]

Just to add, there's details on EP Dampening & how to check & clear this in the following guide:
https://www.cisco.com/c/en/us/td/docs/switches/datacenter/aci/apic/sw/4-x/basic-configuration/Cisco-APIC-Basic-Configuration-Guide-42x/Cisco-APIC-Basic-Configuration-Guide-42x_chapter_0101.html#Cisco_Task.dita_b4647f36-3e4f-43bc-bea3-7572badebc01

Robert