Avi 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 cluster VIP is configured there must be a valid IP address only. An FQDN cannot be configured for cluster VIP.

In addition, cluster configuration with DNS hostnames is not supported for write access vCenter or NSX-T clouds where the Service Engines' Management IP address is statically allocated by the Controller. It is supported for these cloud types if the Service Engines' Management IP address assignment is using DHCP and the DHCP server provides DNS server information that allows the Service Engine to resolve the Controller DNS hostnames.

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.