This article contains information about how to configure Global Server Load Balancing (GSLB) in Active-Active mode.

Background

In Active-Active mode both the NetScaler appliances services the network traffic for the domains for which the appliance is authoritative. With this setup, Web or application content can be mirrored in geographically dispersed locations. This ensures that data is consistently available at each distributed data center.

Instructions

Complete the following steps to create GSLB setup in active-active mode.

1. Create two sites.

2. Create GSLB virtual servers and GSLB services.

3. Bind the Local and Remote GSLB services to GSLB virtual servers.

4. Create the ADNS services.

5. Bind the domain to the GSLB virtual servers.

Note: In this setup, both Site A and Site B are active and host the domain is www.example.com. Create a load balancing setup with the same virtual IP address as the GSLB service.

Configuring Site A

Complete the following steps to configure Site A:

1. Run the following command to enable the GSLB and the Load Balancing features on the appliance:
   enable ns feature LB GSLB

2. Add the authoritative DNS (ADNS) service. ADNS service can be configured with any NetScaler–owned IP address (MIP/SNIP).Once the ADNS service is configured NetScaler appliance is authoritative for that domain and responds to DNS queries. Run the following command to add a ADNS service:
   add service adns_svc 192.168.251.205 adns 53

3. Run the following command to add the local and remote GSLB site:
   Note: GSLB site hosted on a NetScaler appliance is local to that appliance and remote to a different NetScaler appliance
   add gslb site sitea LOCAL 192.168.251.201 -publicIP 192.168.251.201
   add gslb site siteb REMOTE 192.168.253.201 -publicIP 192.168.253.201

4. Run the following command to add the GSLB virtual server with the required lbmethod and service type for the type of network traffic. A GSLB virtual server is associated with one or more GSLB services and load balances the network traffic among them:
   add gslb vserver gvserverhttp http -lbmethod RTT

5. Run the following command to add the virtual server for load balancing the servers and services at site A and bind the service to virtual server:
   add service server-a 192.168.152.10 HTTP 80
   add lb vserver vservera HTTP 192.168.251.202 80
   bind lb vserver vservera server-a

6. Run the following command to add the GSLB service for the local site A:
   Note: Ensure that the local GSLB service have the same IP address as the load balancing virtual server added in step 5.
   add gslb service gslb-svc-a 192.168.251.202 HTTP 80 -siteName sitea
   bind gslb vserver gvserverhttp -serviceName gslb-svc-a

7. Run the following command to add the GSLB service for the remote site B and bind it to the GSLB virtual server:
   add gslb service gslb-svc-b 192.168.253.202 HTTP 80 -publicIP 192.168.253.202 -publicPort 80 -siteName siteb
   bind gslb vserver gvserverhttp -serviceName gslb-svc-b

8. Run the following command to configure a domain for the GSLB virtual server:
   bind gslb vserver gvserverhttp -domainName www.example.com

Configuring Site B

Complete the following steps to configure Site B:

1. Run the following command to enable the GSLB and load balancing feature on the appliance:
   enable ns feature LB GSLB

2. Run the following command to add the authoritative DNS service:
   add service adns_svc 192.168.253.205 adns 53

3. Run the following commands to add remote and local GSLB sites:
   add gslb site sitea REMOTE 192.168.251.201 -publicIP 192.168.251.201
   add gslb site siteb LOCAL 192.168.253.201 -publicIP 192.168.253.201

4. Run the following commands to add the local GSLB virtual server for HTTP network traffic with RTT as the lbmethod:
   add gslb vserver gvserverhttp http -lbmethod RTT

5. Run the following commands to add the virtual server for load balancing the servers and services at site A and bind the service to virtual server:
   add service server-b 192.168.152.11 HTTP 80
   add lb vserver vserverb HTTP 192.168.253.202 80
   bind lb vserver vserverb server-b

6. Run the following commands to add the GSLB service for the local site A with virtual server as a local GSLB service:
   Note: Ensure that the local GSLB service have the same IP address and the port as the load balancing virtual server added in step 5.
   add gslb service gslb-svc-b 192.168.253.202 HTTP 80 -siteName siteb
   bind gslb vserver gvserverhttp -serviceName gslb-svc-b

7. Run the following commands to add the GSLB service for the remote site B and bind it to the configured GSLB virtual server:
   add gslb service gslb-svc-a 192.168.251.202 HTTP 80 -publicIP 192.168.251.202 -publicPort 80 -siteName sitea
   bind gslb vserver gvserverhttp -serviceName gslb-svc-a

8. Run the following command to configure the domain for the GSLB virtual server:
   bind gslb vserver gvserverhttp -domainName www.example.com

CTX122619 - DNS and GSLB Primer