I am interesting if it is possible to change vPC keep alive link IP address without disruption traffic flow on working vPC domain ? If yes please share procedures ?
Thanks in advance,
Changing the IP address of the vPC peer keepalive is possible without causing any disruption to the operation of the vPC members. Undertaking a change to the IP address would be seen as a peer keepalive link failure, and as per the vPC Peer-Keepalive Failure section of the Cisco NX-OS Software Virtual PortChannel: Fundamental Concepts design guide:
"If connectivity of the peer-keepalive link is lost but peer-link connectivity is not changed, nothing happens; both vPC peers continue to synchronize MAC address tables, IGMP entries, and so on. The peer-keepalive link is mostly used when the peer link is lost, and the vPC peers use the peer keepalive to resolve the failure and determine which device should shut down the vPC member ports."
Based on the above, the procedure would simply be to change the IP address of the interface being used for the keepalive e.g., the IP address of the mgmt. 0 interface, and then change the peer-keepalive destination <address> used within the vpc domain <domain_id> configuration.
I have done this in production as well without disruption. The original installer had the peer-keepalive link going through the peer link which is not a good idea. I was able to move it to the management interface without disruption.
The peer-keepalive link can be changed during production without disruption to traffic flow. The procedure is:
vpc domain <vpc_domain_id>
peer-keepalive destination <peer-switch keepalive IP> source <switch keepalive IP> vrf <peer-keepalive vrf>