Now many are leveraging Netscaler GSLB to setup complex Geo based load balancing across different regions using built-in health checks and proximity based upon latency to endpoint and such. Citrix have also made some investments into the feature with Zones feature in XenDesktop which works together with GSLB to allow for Optimal Gateway Routing to redirect a user to the cloest datacenter. GSLB however is from Citrix not supproted in Azure. Now sometimes you just need a geo based load balancing solution, which can be easily incorperated with Azure, this is where Traffic Manager comes in!
Traffic Manager is a GEO based load balancer which can be easily integrated with Azure where endpoints can either reside there, or external endpoint and we can have different health check and load balancing options configured.
now to setup Traffic Manager against an Azure Endpoint, you need to ensure that your public IP in Azure have a DNS prefix configured if not they will not appear in the wizard. So first thing we need to create a traffic manager deployment, which is available from the marketplace.
Routing method performance means that it is going to use based upon latency from there the latency comes from.
Now note that Traffic Manager only has a basic health check, it can do HTTP or HTTPS on a specific port and path. This can be for instance pointed to a custom web page on the NetScaler to ensure that it is available.
Next thing we need to do is add endpoints to traffic manager. The first thing is to add our Azure endpoint, which has a load balancer configured from before. Target Resource VIP is in this example our load balanced HA-pair VPX which Is described here –> http://msandbu.org/setting-up-high-availability-netscaler-in-microsoft-azure-arm/
Now we have added the Azure endpoint, we need to add the NetScaler service on-premises.
In this case we just need to go back to traffic manager and choose endpoints and add the external endpoint pointing to the on-premises NetScaler
NOTE: You need to specify Location here so traffic manager can store the FQDN with IP in a geo database.
now after we have added the endpoints make sure that both endpoints are online, also note that the service which is going to be published using traffic manager will have a DNS prefix of servicename.trafficmanager.net
So for it to work with a proper setup we need to configure a CNAME to point to that DNS name, since CNAMES are just aliases for other domains.
So now with leveraging Traffic Manager with NetScaler we can have a geo based load balancing without using GSLB (NOTE IT does not support Zones in Citrix) but can be an cost effective way to do geo LB.