To mitigate the challenges of scale, lack of flexibility, and performance, network architectures today allow for virtual machines (VMs) and applications to be provisioned, changed, and deleted on demand. This agility, though, poses a challenge for security administrators because they have limited visibility into the IP addresses of the dynamically provisioned VMs and the plethora of applications that can be enabled on these virtual resources. Firewalls (hardware-based and VM- Series models) support the ability to register IP addresses, IP sets (IP ranges and subnets), and tags dynamically. The IP addresses and tags can be registered on the firewall directly or from Panorama. You can also automatically remove tags on the source and destination IP addresses included in a firewall log.
https://docs.paloaltonetworks.com/pan-os/10-0/pan-os-admin/policy/register-ip-addresses-and- tags-dynamically.html