A cold standby cluster is a high availability deployment that

• operates with some controllers as active and others as standby,

• enables standby controllers to quickly take over when an active controller fails, and

• allows administrators to manually initiate a switchover to maintain cluster services.

Additional information

In a Cisco APIC cluster, administrators typically configure at least three active controllers and one or more standby controllers for resilience. The active controllers manage traffic under normal conditions, while standby controllers remain ready to replace any active controller if needed. The switch to a standby controller is performed manually to ensure controlled recovery during failures. This arrangement maintains network stability and reduces downtime.