Starting with NSX Advanced Load Balancer 22.1.5, CNAME is also available as one of the down responses when a GSLB Service is down.

Follow the below steps to configure CNAME as a down response for a GSLB Service:

  • Log in to NSX Advanced Load Balancer CLI and use theconfigure gslbservice <GSLB Service Name > mode to perform the configuration changes.

  • Use gslb_service_down_response_cname as the CNAME type for the down response.

  • Specify the fallback CNAME.

[admin:controller-1-site-a]: > configure gslbservice gs-1
Updating an existing object. Currently, the object is:
+----------------------------------+--------------------------------------------------+
| Field                            | Value                                            |
+----------------------------------+--------------------------------------------------+
| uuid                             | gslbservice-3b271257-9d30-4429-8fd5-ac25285a9720 |
| name                             | gs-1                                             |
| domain_names[1]                  | foo.avi.com                                      |
| groups[1]                        |                                                  |
|   name                           | gs-1-pool                                        |
|   priority                       | 9                                                |
|   algorithm                      | GSLB_ALGORITHM_ROUND_ROBIN                       |
|   members[1]                     |                                                  |
|     ip                           | 1.1.1.1                                          |
|     ratio                        | 1                                                |
|     enabled                      | True                                             |
|     resolve_fqdn_to_v6           | False                                            |
|     preference_order             | 1                                                |
|   enabled                        | True                                             |
|   manual_resume                  | False                                            |
| down_response                    |                                                  |
|   type                           | GSLB_SERVICE_DOWN_RESPONSE_NONE                  |
| controller_health_status_enabled | True                                             |
| health_monitor_scope             | GSLB_SERVICE_HEALTH_MONITOR_ALL_MEMBERS          |
| enabled                          | True                                             |
| use_edns_client_subnet           | True                                             |
| wildcard_match                   | False                                            |
| site_persistence_enabled         | False                                            |
| pool_algorithm                   | GSLB_SERVICE_ALGORITHM_PRIORITY                  |
| min_members                      | 0                                                |
| resolve_cname                    | False                                            |
| is_federated                     | True                                             |
| tenant_ref                       | admin                                            |
| topology_policy_enabled          | False                                            |
+----------------------------------+--------------------------------------------------+
[admin:controller-1-site-a]: gslbservice> down_response
[admin:controller-1-site-a]: gslbservice:down_response> type gslb_service_down_response_cname
Overwriting the previously entered value for type
[admin:controller-1-site-a]: gslbservice:down_response> fallback_cname cname1.foo.avi.com
[admin:controller-1-site-a]: gslbservice:down_response> save
[admin:controller-1-site-a]: gslbservice> save
+----------------------------------+--------------------------------------------------+
| Field                            | Value                                            |
+----------------------------------+--------------------------------------------------+
| uuid                             | gslbservice-3b271257-9d30-4429-8fd5-ac25285a9720 |
| name                             | gs-1                                             |
| domain_names[1]                  | foo.avi.com                                      |
| groups[1]                        |                                                  |
|   name                           | gs-1-pool                                        |
|   priority                       | 9                                                |
|   algorithm                      | GSLB_ALGORITHM_ROUND_ROBIN                       |
|   members[1]                     |                                                  |
|     ip                           | 1.1.1.1                                          |
|     ratio                        | 1                                                |
|     enabled                      | True                                             |
|     resolve_fqdn_to_v6           | False                                            |
|     preference_order             | 1                                                |
|   enabled                        | True                                             |
|   manual_resume                  | False                                            |
| down_response                    |                                                  |
|   type                           | GSLB_SERVICE_DOWN_RESPONSE_CNAME                 |
|   fallback_cname                 | cname1.foo.avi.com                               |
| controller_health_status_enabled | True                                             |
| health_monitor_scope             | GSLB_SERVICE_HEALTH_MONITOR_ALL_MEMBERS          |
| enabled                          | True                                             |
| use_edns_client_subnet           | True                                             |
| wildcard_match                   | False                                            |
| site_persistence_enabled         | False                                            |
| pool_algorithm                   | GSLB_SERVICE_ALGORITHM_PRIORITY                  |
| min_members                      | 0                                                |
| resolve_cname                    | False                                            |
| is_federated                     | True                                             |
| tenant_ref                       | admin                                            |
| topology_policy_enabled          | False                                            |
+----------------------------------+--------------------------------------------------+
[admin:controller-1-site-a]: >

In the configuration example shown above, the fallback CNAME is configured as cname1.foo.avi.com.