Good morning,
I'm hoping to get some advice on a possible solution that we are having with joining a replacement vpc leaf switch into ACI. We had a series of leaf switch failures as their SSD write limits were hit, causing them to required hardware replacement. 5 of the 6 switches that were replaced joined the fabric without issue, but the 6th switch will not join the fabric and remains in the Unreachable Nodes section. With only the hostname being pushed to the switch.
Our theory after much reading is that this issue was caused when a slight variation of the required model (a N9K-C3972PX-E instead of a N9K-C3972PX) was incorrectly sent as a replacement, and when attempting to add this into the fabric it caused an issue as it is part of a vpc pair. I assume ACI saw the model difference and so issued a different Infra IP to the switch.
We now have the correct model, but it still will not join the fabric and is not being issued the Infra IP of the old failed switch.
Having looked through the ACI config, under Fabric > Access Policies > Switch Policies > Policies there is the Virtual Port Channel default section. Within here, there is a current setting for the vpc switch pair called 'Explicit VPC Protection Groups', and the IP of the replacement switch is now different to the IP within this section. Could this setting be the issue? If so, will amending this group have an impact on the second switch in the vpc pair that is currently working and serving traffic?
I was wondering if anyone had come across a similar issue that they were able to resolve? Or whether someone could advise if this is indeed being caused by the change of Infra IP, and if so is there a way to manually change this IP to the previous one? Our old ACI fabric is still running the old 2.0.1(n) version, and I cannot see a way to amend the IP.
Unfortunately we have hardware support only on these devices as the are end of support, so a TAC case cannot be raised, and need to try and resolve this issue to tide us over until we have migrated all networks onto our new ACI fabric.
Many thanks in advance.
