Core issue
These error messages appear in the logs:
%C4K_REDUNDANCY-4-KEEPALIVE_WARNING: Keepalive messages from peer Supervisor are missing for 162 seconds
%C4K_REDUNDANCY-3-PEER_RELOAD: The peer Supervisor is being reset because keepalive message(s) not received
The Default keep-alive timer value is nine seconds and Default keep-alive threshold value is 18 seconds.
This means that keep-alive messages are sent every nine seconds and it is allowed to miss a total of 18 keep-alive messages before it declares that something is wrong. This gives a total of 162 seconds or 2.7 mins of keep-alive timeout. It is possible that the Supervisor is too busy to handle keepalive.
In some scenarios, the logs says that the system returned to ROM by Stateful Switchover. In redundant systems, after 162 seconds the switch triggers a redundancy failover.
Resolution
In most of these cases, this is a transient issue which happens only once. As a workaround, you can reseat the Primary Supervisor module and then force it to become active and then monitor the switch for further error messages.
If the error message is still seen then for further assistance and support, use the TAC Service Request Tool in order to open a service request with the Cisco Technical Support.
