This article describes how to use the Global Server Load balancing (GSLB) location database in Content Switching.

Background

GSLB location database can be used if you:

• Have a long list of IP/subnet address ranges for which you need to create ContentSwitching policies.

• Are using Source IP persistence and the same client is coming with different IP addresses (going through megaproxies).

Instructions

Complete the following procedure:

1. Create a file under /var/netscaler/locdb directory.
   In NetScaler format, the file would look like the following:
   root@NS_2# more aol.db

   NSGEO1.0
   Start
   64.12.96.1, 64.12.127.254, aol
   10.1.1.1, 10.1.1.254, yahoo
   - - - - - - ctxs
   - - - - - - - xyz
   

2. Enable GSLB  feature:
   NS_2> en feature gslb

3. Load the file using the following command:
   NS_2> add locationfile aol.db
   NS_2> sh locationparameter

   Static Proximity
   ----------------
   Flushing: Idle; Loading: Idle;
   Context: geographic
   Qualifier 1 label: Continent
   Qualifier 2 label: Country
   Qualifier 3 label: Region
   Qualifier 4 label: City
   Qualifier 5 label: ISP
   Qualifier 6 label: Organization
   Location file (format: netscaler):
    aol.db
   Current static entries: 4  Current custom entries: 0
    Done

4. To check whether an IP address is part of the file or not, from a shell prompt run:
   #nsmap –t –d

   Enter IP address to to test (dot notation) or q to exit: 10.1.1.2 -> Enter an IP addr here and hit return
   ============ Result for ip 10.1.1.2 ==============
   Found in the range from 10.1.1.1 to 10.1.1.254
    Qualifiers:
           yahoo.*.*.*.*.*
   Enter IP address to to test (dot notation) or q to exit:
   

   Note: Whenever you change entries in the file, you must reload it using the same add locationfile command and verify using sh locationparameter

5. Bind over to Content Switching:
   add cs policy yahoo –rule  "CLIENT.IP.SRC.MATCHES_LOCATION(\"yahoo.*.*.*.*.*\")"
   add cs policy aol -rule "CLIENT.IP.SRC.MATCHES_LOCATION(\"aol.*.*.*.*.*\")"

6. Use the policies in the Content Switching vServer and bind them to respective load balancing vServers with different priorities:
   bind cs vs testcs -policyName yahoo vyahoo -priority 3
   bind cs vs testcs -policyName aol vaol -priority 4

   With this, when a client request comes within the range 64.12.96.1- 64.12.127.254, a request goes to vaol (which is the aol vServer).
   If the client comes with IP address within the range 10.1.1.1 - 10.1.1.254, a request goes to the Yahoo vServer.

Citrix Documentation - Global Server Load Balancing