NetScaler ingress controller

Creating monitors for applications

December 31, 2023

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The topic covers how to create monitors for applications which would help to load balance applications better.

NetScaler supports two types of monitors.

Built-in monitors
Custom monitors

A smart annotation on the NetScaler Ingress Controller can be used for creating various types of monitors for your applications. You can choose between creating a monitor based on a built-in monitor, or creating a custom monitor that uses a script that you write to monitor the service. Once you have chosen or created a monitor, you can use the smart annotation to manage your application monitor lifecycle.

Smart annotation for monitor

You can use the ingress.citrix.com/monitor smart annotation which can be used to create a monitor of your choice. The NetScaler Ingress Controller internally creates the monitor and bounds it to the right service.

Configure a built-in monitor

The NetScaler appliance contains various built-in monitors that you can use to monitor your services. These built-in monitors handle most of the common protocols. Based on your application needs, you can choose the built-in monitor which suits your application.

Here is an example of using an HTTP monitor with the help of smart annotation.

ingress.citrix.com/monitor: '{"frontend":{"type":"http", "httpRequest":"GET /", "respcode":"200", "retries":"2"}}'

In this example, a service called frontend is configured with an HTTP monitor which sends a GET request and expects the HTTP response code 200. When the NetScaler Ingress Controller gets this event, it creates a monitor and binds the monitor with the corresponding service.

A sample Ingress is shown as follows:

HttpInline

Corresponding ADC configurations are as follows:

HttpInlineADC

Configure a custom monitor

In addition to built-in monitors, you can use custom monitors to check the state of your services. The NetScaler appliance provides several types of custom monitors based on scripts that are included with the NetScaler operating system. These monitors can be used to determine the state of services based on the load on the service or network traffic sent to the service. These are the inline monitors, user monitors, and load monitors. You can either use the provided functionality or you can create your own scripts and use those scripts to determine the state of the service to which the monitor is bound.

Following are the scripts which are provided by NetScaler ADC:

CustomMonitor

Here, we are using a user monitor for SFTP application. The name of the service used here is sftp and type of monitor is USER. Providing the script nssftp.pl which is already available in NetScaler.

  ingress.citrix.com/monitor: '{"sftp":{"type":"USER", "scriptname":"nssftp.pl", "scriptargs":"file=/sftp/incoming/test.log;user=admin;password=admin"}}'

A sample Ingress is shown as follows:

MonitorIngress

When this Ingress is applied for the service sftp, a user monitor is created on the NetScaler and bound to the service.

Corresponding ADC configurations are shown as follows:

MonitorConfig

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NetScaler Secure Deployment Guide

Creating monitors for applications

December 31, 2023

Contributed by:

Creating monitors for applications

Smart annotation for monitor

Configure a built-in monitor

Configure a custom monitor

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