Cisco APIC Cluster Failure Scenarios
Problem: An APIC node fails within the cluster. For example, node 2 of a cluster of 5 APICs fails.
There are two available solutions:
Leave the target size and replace the APIC.
Reduce the cluster size to 4, decommission controller 5, and recommission it as APIC 2.The target size remains 4, and the operational size is 4 when the reconfigured APIC becomes active.
You can add a replacement APIC to the cluster and expand the target and operational size. For instructions on how to add a new APIC, refer to the Cisco APIC Management, Installation, Upgrade, and Downgrade Guide.