This article describes how to monitor NetScaler appliances that are part of the high availability setup with route monitors.

Background

In a high availability setup, a route monitor on each appliance watches the internal routing table to ensure that a route entry for reaching a particular network is always available. If the route entry is not available, the state of the route monitor changes to DOWN. Route monitors are useful in a non-INC mode high availability setup where you want the non-reachability of a gateway from a primary appliance to be one of the conditions for High Availability failover.

In this scenario, the IP addresses of the NetScaler appliances are 172.16.15.20 and 172.16.15.21. The default gateway for the appliances are 172.16.15.1, which the appliances are directly connected to two different core Switches. In this article, route 172.16.15.0/24 is being monitored for high availability.

Instructions

NetScaler GUI

To monitor appliances that are part of the high availability setup with route monitors, complete the following procedure:

1. To create and bind the route monitor, select System > High Availability > Route Monitors > Configure, as shown in the following screen shot:

   

2. Select Network > Routes > Add to create the static route.

3. Enable the Monitored Static Route option.

   

NetScaler CLI

To configure the route monitors from the command line interface, run the following commands:
bind ha node 1 -routeMonitor 172.16.15.0 255.255.255.0
add route 172.16.15.0 255.255.255.0 172.16.15.1 -distance 1 -cost 0 -weight 1 -msr ENABLED -monitor ping-default

If the monitored static route option is disabled on static routes, a unreachable static route can remain in the internal routing table. 

• Route monitors are propagated by the appliances and exchanged during synchronization.
• Route monitors are active only in the current primary appliance.
• The NetScaler appliance always displays the state of a route monitor as UP irrespective of whether the route entry is available or not in the internal routing table.
• A route monitor starts monitoring its route after 180 seconds in the following cases:
  Note: This is done to allow dynamic routes to be learnt, which might take 180 seconds.
  • restart
  • failover
  • set route6 command for v6 routes
  • set route msr enable/disable command for v4 routes
  • adding a new route monitor

Citrix Documentation -  Configuring Route Monitors
Citrix Documentation - Limiting Failovers Caused by Route Monitors in non-INC mode