Posted on February 3, 2020 5:18 pm
 |  Asked by infosec infosec
 |  339 views
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Hello everybody,

I’d like to have your opinion about this. I see that my MLAG are “inconsistent” (show mlag) and I get the following output when I run the command: “show mlag config-sanity”. Could you tell me what I have to check to solve this issue?

Peer1:

Global configuration inconsistencies:
Feature Attribute Local value Peer value
————– ————— —————– ———-
bridging 1 – True
bridging 100 – True
bridging 202 – True
bridging 21 – True

Peer2:

Global configuration inconsistencies:
Feature Attribute Local value Peer value
————– ————————— —————– ———-
bridging mac-learning vlan 1 True –
bridging mac-learning vlan 21 True –
bridging mac-learning vlan 100 True –
bridging mac-learning vlan 202 True –

Best regards,

Greg.

2
Posted by Alla Anunitya
Answered on February 4, 2020 7:02 am

Hi Greg,

I have replicated the issue in the lab environment and I was seeing the following mlag inconsistencies.

Scenario 1:

PeerA:

Global configuration inconsistencies:
Feature Attribute Local value Peer value
-------------- ----------------------------------- ----------------- ----------
bridging 1 - True
bridging 4094 - True

PeerB:

Global configuration inconsistencies:
Feature Attribute Local value Peer value
------------- -------------------------------------- ----------------- ----------
bridging mac-learning vlan 1 True -
bridging mac-learning vlan 4094 True -

But I noticed that both the peers are running different EOS versions.

PeerA - Software image version: 4.20.11M

PeerB - Software image version: 4.23.0F

Once I have upgraded both the peers to a same version code 4.23.0F, there were no inconsistencies.

Scenario 2:

PeerA - Software image version: 4.23.0F

PeerB - Software image version: 4.23.0F

PeerA:

No global configuration inconsistencies found.

No per interface configuration inconsistencies found.

PeerB:

No global configuration inconsistencies found.

No per interface configuration inconsistencies found.

Could you please check and confirm if both the MLAG peers in your setup are running the same code version?

If the mlag peers are running different code versions, the above inconsistencies are expected due to differences in the implementations of the code versions.

If you have any concerns, kindly raise a case with support@arista.com

Regards
Anu

Nice catch!
(John Gill at February 5, 2020 3:18 pm)
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Posted by John Gill
Answered on February 4, 2020 4:21 pm

Hello Greg,

What do you see if you check the following for one of these VLANs?
show vlan id 21
show vlan 21 trunk group
show running-config | grep mac

Regards,
John

0
Posted by Sreelekha
Answered on February 4, 2020 4:24 pm

Hi Greg,

Thanks for writing to the forum.

"Inconsistent" indicates that the configuration on both the MLAG devices is not uniform.

The command show mlag config-sanity displays the configuration that is not uniform on both the devices. The local value indicates the status of the configuration on the device the command was run and the peer-value refers to the MLAG peer device.

In your case, the output on peer1 indicates the vlans 1,21,100,202 are true under peer value, but not under local value. This means the vlans are not present on peer1 but they are present on peer2.

Although, this is not a problem as such, it is recommended to have identical configuration on both the devices.The command show mlag config-sanity serves sanity check purpose .

Cheers,
Sreelekha

0
Posted by infosec infosec
Answered on February 5, 2020 9:57 am

Hi everybody,

Thank you for your answers. Actually, I was in the case described by "Alla Anunitya". The configuration was the same on both switches but there were running differents versions of EOS (4.21.7M and 4.21.2F). I upgraded one of them. Now both switches are running version 4.21.7M and the consistency error isn't present anymore.

So thank you very much for your help.

Cheers,

Greg.

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