I am reading about High Availability and I can not understand the following I read: On failover the primary IP migrates to the backup server BUT so must the MAC address.
Specifically I read that every machine has a unique address MAC that can be used by all interfaces in the machine. I don't get this part. Doesn't the MAC belong to the NIC? What is meant by interfaces in this sentence?
Also on failover the clients must update their IP/MAC mapping and found 3 ways for this one of which is by using a custom MAC and move it from primary to backup along with the public IP. How is this possible? Do high availability software e.g. Pacemaker do this? How?