NSX Advanced Load Balancer Controller cluster can be configured with DNS hostnames instead of IP addresses.

Cluster configuration can be changed to use DNS hostnames instead of IP addresses by editing node management IP or hostname in the Administration > Controller > Nodes page. It triggers a new Cluster configuration process and updates all nodes to use DNS hostnames.

DNS is resolved when a secure connection is established between Controllers. This usually happens when the cluster is configured or any of the nodes is rebooted. SEs resolve DNS hostname of the Controller when establishing a secure connection to the Controller. This usually happens when the SE is first created and when either an SE or a Controller reboots.
Note: If the Controllers are clustered using FQDNs, write access is not supported for VMware vCenter and NSX-T clouds where the Service Management IP is statically allocated by the Controller. There is no functionality to program the DNS server to resolve the Controller FQDNs.

The cluster configuration process takes the DNS information of the leader node and updates it in the new follower nodes. All nodes can reach the DNS server that is configured in the Administration > System Settings > DNS/NTP page of the leader.

SEs can initiate connection using IP address from the VM metadata but are automatically switched to use DNS hostname for the Controller nodes. So it is important for SEs to use the correct DNS server to resolve Controller DNS hostname.