ZABBIX 1.8 – 9 WEB Monitoring

April 13, 2014 Raj ZABBIX 1.8 0

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9 WEB Monitoring

1 Goals

Zabbix WEB Monitoring support is developed with the following goals:

  • Performance monitoring of WEB applications
  • Availability monitoring of WEB applications
  • Support of HTTP and HTTPS
  • Support of complex scenarios consisting of many steps (HTTP requests)
2009/08/13 16:04
· richlv

2 Overview

Zabbix provides effective and very flexible WEB monitoring functionality. The module periodically executes WEB scenarios and keeps collected data in the database. The data is automatically used for graphs, triggers and notifications.

The following information is collected per each step of WEB scenario:

  • Response time
  • Download speed per second
  • Response code

Zabbix also checks if a retrieved HTML page contains a pre-defined string.

Zabbix WEB monitoring supports both HTTP and HTTPS.

When running a web scenario, Zabbix always follows redirects.

To use HTTP proxy, set environment variable http_proxy for Zabbix server user. For example, http_proxy=http://proxy_ip:proxy_port.

2009/08/13 16:05
· richlv

3 WEB Scenario

Scenario is set of HTTP requests (steps), which will be periodically executed by Zabbix server. Normally a scenario is defined for one particular part of functionality of a WEB application. Scenarios are very convenient way of monitoring user experience.
WEB Scenario is linked to a host application for grouping.
WEB Scenario is periodically executed and consists of one or more Steps.
All cookies are preserved during execution of a single scenario.

Example 1

Monitoring of Zabbix GUI

If we want to monitor availability and performance of Zabbix GUI, we have to login, check how quickly Overview and Status of Triggers screens work and then logout.

The scenario may have the following steps:

  1. Login
  2. Go to Overview screen
  3. Go to Status of Triggers screen
  4. Logout

If a step cannot be performed, execution of scenario fails.

Parameter Description
Application WEB scenario will be linked to this application. The application must exist.
For example: Zabbix server
Name Name of the WEB scenario.
The name will appear in Monitoring → Web
For example: Zabbix GUI
Update interval How often this scenario will be executed, in seconds.
For example: 60
Agent Zabbix will pretend to be the selected browser. Useful for monitoring of web sites which generate different content for different web browsers.
For example: Opera 9.02 on Linux
Status Active: active scenario, it will be executed
Disabled: disabled scenario, it will NOT be executed
Variables List of macros to be used in configuration of the steps.
Syntax:
{macro}=value
The macro {macro} will be replaced by “variable” in step's URL and POST variables.
For example:
{user}=guest
{password}=guest
Note: Variables are not URL-encoded.
Steps Steps of the scenario.

As soon as a scenario is created, Zabbix automatically adds the following items for monitoring and links them to the selected application. Actual scenario name will be used instead of “Scenario”.

Item Description
Download speed for scenario 'Scenario' This item will collect information about download speed (bytes per second) of the whole scenario, i.e. average for all steps.
Item key: web.test.in[Scenario,,bps]
Type: float
Failed step of scenario 'Scenario' This item keeps number of failed step of the scenario. If all steps are executed successfully, 0 is returned.
Item key: web.test.fail[Scenario]
Type: integer

Web monitoring items are added with 30 day history retention and 90 day trend retention periods.

These items can be used to create triggers and define notification conditions.

Example 1

Trigger “WEB scenario failed”

The trigger expression can be defined as: 

{host: web.test.fail[Scenario].last(0)}#0

Do not forget to replace the Scenario with real name of your scenario.

Example 2

Trigger “WEB application is slow”

The trigger expression can be defined as: 

{host: web.test.in[Scenario,,bps].last(0)}<10000

Do not forget to replace the Scenario with real name of your scenario.

2009/08/13 16:06
· richlv

4 WEB Step

Step is basically a HTTP request. Steps are executed in a pre-defined order.

Parameter Description
Name Name of the step.
For example: Login
URL URL
For example: www.zabbix.com
Post HTTP POST variables, if any.
For example:
id=2345&userid={user}
If {user} is defined as a macro of the WEB scenario, it will be replaced by its value when the step is executed.
The information will be sent as is, variables are not URL-encoded..
Timeout Do not spend more than Timeout seconds for execution of the step. Actually this parameter defines maximum time for making connection to the URL and maximum time for performing an HTTP request. Therefore, Zabbix will not spend more than 2 x Timeout seconds on the step.
For example: 15
Required The string (given as POSIX extended regular expression) must exist in retrieved content.
Otherwise this step fails. If empty, any content will be accepted.
For example: Homepage of Zabbix
Status codes List of HTTP status codes to be considered as success. If retrieved status code is not in the list, this step fails.
If empty, any status code is accepted.
For example: 200,210

As soon as a step is created, Zabbix automatically adds the following items for monitoring and links them to the selected application. Actual scenario and step names will be used instead of “Scenario” and “Step” respectively.

Item Description
Download speed for step 'Step' of scenario 'Scenario' This item will collect information about download speed (bytes per second) of the step.
Item key: web.test.in[Scenario,Step,bps]
Type: float
Response time for step 'Step' of scenario 'Scenario' This item will collect information about response time of the step in seconds. Response time is counted from the beginning of the request until all information has been transferred.
Item key: web.test.time[Scenario,Step]
Type: float
Response code for step 'Step' of scenario 'Scenario' This item will collect response codes of the step.
Item key: web.test.rspcode[Scenario,Step]
Type: integer

Web monitoring items are added with 30 day history retention and 90 day trend retention periods.

These items can be used to create triggers and define notification conditions.

Example 1

Trigger “Zabbix GUI login is too slow”

The trigger expression can be defined as: 

{zabbix: web.test.time[ZABBIX GUI,Login].last(0)}>3
2009/08/13 16:43
· richlv

5 Real life scenario

Let's use Zabbix Web Monitoring to monitor the web interface of Zabbix. We want to know if it is available, provides the right content and how quickly it works.
First we must log in with our user name and password.

Step 1

Add a new host application.

Go to Configuration → Hosts, then click on Applications next to the host you want to use for web monitoring. In the application section click on Create application.

This step is not required if you already have a suitable application. You may also want to create a host if one does not exist.

Step 2

Add a new web scenario.

We will add a scenario to monitor the web interface of Zabbix. The scenario will execute a number of steps.

Go to Configuration → Web, select the host in the dropdown, then click on Create scenario.

In the new scenario form, click on Select next to the Application field to choose the application we just created.

Note that we also create two macros, {user} and {password}.

Step 3

Define steps for the scenario.

Click on Add button in the Steps section to add individual steps.

Web scenario step 1

We start by checking that the first page responds correctly, returns with HTTP response code 200 and contains text “SIA Zabbix”.

When done configuring the step, click Add.

Web scenario step 2

We continue by logging in to the Zabbix frontend, and we do so by reusing the macros (variables) we defined on the scenario level, {user} and {password}.

Note that Zabbix frontend uses JavaScript redirect when logging in, thus first we must log in, and only in further steps we may check for logged-in features. Additionally, the login step must use full URL to index.php file.

All the post variables must be on a single line and concatenated with & symbol. Example string for logging into Zabbix frontend: 

name=Admin&password=zabbix&enter=Enter

If using the macros as in this example, login string becomes: 

name={user}&password={password}&enter=Enter

Web scenario step 3

Being logged in, we should now verify the fact. To do so, we check for a string that is only visible when logged in – for example, Profile link appears in the upper right corner.

Web scenario step 4

Now that we have verified that frontend is accessible and we can log in and retrieve logged-in content, we should also log out – otherwise Zabbix database will become polluted with lots and lots of open session records.

Complete configuration of steps

A complete configuration of web scenario steps should look like this:

Step 4

Save the finished web monitoring scenario.

The list of applications and linked scenarios will appear in Monitoring → Web:

Click on the scenario name to see more detailed statistics:

2009/08/13 17:08
· richlv

Data source: Zabbix

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