NSX Advanced Load Balancer Service Engines proxy DNS requests to a backend pool of DNS servers. A virtual service with a System-DNS (or similar) application profile is defined as usual. However, a pool of backend servers loaded with DNS software packages must be assigned.

Hosting Manual or Static DNS Entries

NSX Advanced Load Balancer DNS can host manual or static DNS entries. For a given FQDN, you can configure an A, AAAA, SRV, CNAME, or NS record to be returned.

Starting with NSX Advanced Load Balancer release 20.1.1, NSX Advanced Load Balancer supports text record (TXT) record and mail exchanger (MX) record.

  • TXT record: This is used to store text-based information for the configured domain.

  • MX record: This is used in mail delivery based on the configured domain.

Virtual Service IP Address DNS Hosting

NSX Advanced Load Balancer DNS can host the names and IP addresses of the virtual services configured in NSX Advanced Load Balancer. NSX Advanced Load Balancer serves as DNS provider for the hosted virtual services. For complete configuration details, refer to Service Discovery Using IPAM and DNS.

Hosting GSLB Service DNS Entries

The NSX Advanced Load Balancer DNS virtual service can host GSLB service DNS entries, and automatically update its responses based on the application service health, service load and proximity of clients to sites implementing the application service. NSX Advanced Load Balancer GSLB automatically populates these DNS entries. For more information on NSX Advanced Load Balancer GSLB, refer to:

DNS for NSX Advanced Load Balancer -hosted Virtual Services

NSX Advanced Load Balancer-SE-hosted DNS virtual services translate the FQDNs of NSX Advanced Load Balancer-hosted virtual services into IP addresses. This configuration does not require pool assignment, as the translation is completely done within the SE VMs.

  • Navigate to Administration > Settings and select DNS Service.

  • Under the DNS Virtual Services section, click the dropdown list to either choose a pre-defined DNS virtual service or create a virtual service.

For more information on configuration steps for DNS virtual services, refer to the configure local DNS virtual service on all active sites that host DNS.

DNS for GSLB

For GSLB configuration, the DNS is not defined by the DNS virtual service but it is configured as a GSLB site object. As part of the GSLB site configuration, a few pre-existing DNS service(s) is (are) designated to serve in the role.

To configure, follow the steps below:

  • Navigate to Infrastructure > GSLB.

  • Click Add New Site button in the Site Configuration tab.

  • Enter relevant information for all fields in the editor. Enable the checkbox for Active Memberoption and click Save and Set DNS Virtual Services.

  • Select from one or more DNS virtual services in the dropdown list and click Save to enable it for the GSLB configuration.

This below screenshot illustrates, the case where there are no DNS virtual services to choose. An active GSLB site does not require a DNS, though it may be preferred, as described in the next section.



High Availability Recommendations for GSLB

For high availability, it is recommended to configure DNS for GSLB on an SE group that is scalable to two or more Service Engines. It is also recommended to implement DNS for GSLB in more than one location. This can be implemented in the following two ways:

  1. You must have at least two geographically separated active GSLB sites. For each site, configure DNS to a scalable SE group.

  2. If only one active site is defined then, ensure a minimum of at least one geographically remote cloud. On that remote cloud, configure DNS for GSLB on a scalable SE group. Also, define all virtual services to support the mission-critical applications running on the original location.