Example of a GSLB setup and configuration

An organization has a geographically dispersed network and has three data centers located in the United States, Mexico, and Colombia. In the configuration related to these locations, these are referred to as US, MX, and CO respectively. At each location, the company has a server farm, which provides the same content and the setup is working as expected. The Citrix ADC appliance at each location is configured through a virtual server with the HTTP protocol on port 80.

The organization has implemented the GSLB setup by adding a site identifier at each site. The site identifier includes a site name and an IP address that is owned by the Citrix ADC appliance and is used for the GSLB communications. Each site has a site local to the appliance. Also, each site has two sites remote to the local appliance. On each site, a GSLB virtual server is created with the same name. This virtual server identifies the website of the organization globally and does not have any IP address associated with it. The setup also has GSLB services configured that point to the load balancing virtual servers configured on each GSLB site by specifying the IP address, protocol, and port number of the respective virtual server. These services are bound to the GSLB virtual server.

Note: In the procedure below, the commands use private IP addresses for the GSLB sites. For public sites and GSLB services, ensure that you use public IP addresses for these sites.

The following table lists the IP addresses and locations used in the example:

IP Address Location Site IP of local Citrix ADC. Site IP of remote location site-MX. Site IP of remote location site-CO. Service IP of remote location site-MX. Service IP of local Citrix ADC. Service IP of remote location site-CO.

When adding a GSLB site, if the site communicates over the internet only then use the “Public IP” field. For example, when there is no site to site VPN connectivity between the GSLB sites.

To configure the GSLB setup with Citrix ADC appliances by using the CLI commands

  1. Enable the GSLB feature, if not already done.

    enable ns feature gslb
  2. Identify a SNIP that for adding local GSLB site.

  3. Add the GSLB site for the local Citrix ADC appliance.

    add gslb site site-US
  4. Add the GSLB sites for the remote Citrix ADC appliances.

    add gslb site site-MX
    add gslb site site-CO
  5. Add the GSLB virtual server that references a service being used in the GSLB setup:

    add gslb vserver gslb-lb HTTP
  6. Add the GSLB services for each site participating in the GSLB setup:

    add gslb service gslb_SVC30 HTTP 80 -siteName site-MX
    add gslb service gslb_SVC10 HTTP 80 -siteName site-US
    add gslb service gslb_SVC20 HTTP 80 -siteName site-CO
  7. Bind the GSLB services to the GSLB virtual server:

    bind gslb vserver gslb-lb -serviceName gslb_SVC10
    bind gslb vserver gslb-lb -serviceName gslb_SVC20
    bind gslb vserver gslb-lb -serviceName gslb_SVC30
  8. Bind the domain to the GSLB virtual server.

    bind gslb vserver gslb-lb -domainName -TTL 30
  9. Add an ADNS service that listens to the DNS queries.

    set service Service-ADNS-1 ADNS 53
Example of a GSLB setup and configuration