POST method example
POST method example Example of monitoring a webform with POST method.

For example you have such simple form:
form action="some-site.com/some-script.cgi" method=post
input type=text name=login value=''
input type=password name=password value=''
input type=submit name='Submit' value='Login'
/form
User fill this form with value login: Peter and password: 1234 and click submit. If everything is Ok, script prints "LoginOk" on the result page.
For making a monitoring task to control this script, create task with next fields:

URL: some-site.com/some-script.cgi
Http Method: choose POST
In "POST parameters" field you should add three strings:
login=Peter
password=1234
Submit=Login
In "Content check" field: LoginOk
Results: HostTracker with every check will fill this form and assume that it is OK if the set keyword LoginOk is returned.

  • CM.Glossary.WebsiteMonitoring
  • CM.Glossary.HTTPMethods
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"

I rely on HostTracker to monitor my servers so I can sleep at night

"
- S.
Escalations. Typical scenarios

As many people know, HostTracker is a sites efficiency monitoring system. One of its main functions is to notify the user of any problems promptly. The efficiency of the notifications and the acceptable level of “detalization” are important. If you send alerts at each “sneeze”, the person will not find the important information in this flow...

I was woken up by an SMS at three a.m.
My site dropped for three minutes, and it raised back itself.
But I could not go back to sleep.
True-life story

As many people know, HostTracker is a sites efficiency monitoring system. One of its main functions is to notify the user of any problems promptly. The efficiency of the notifications and the acceptable level of “detalization” are important. If you send alerts at each “sneeze”, the person will not find the important information in this flow.

We have provided several mechanisms that will help the right people to get the necessary notifications:

  • Separation of the notifications into several groups according to their criticality;
  • No notifications at short-term failures;
  • Report the problem to the manager promptly;
  • Report a prolonged failure to the administration;
  • Use the free alerts first – email, gtalk, and then the paid ones – SMS or phone call;
  • At the contact level – set the working time when this contact should receive the alerts.

 

There are three types of notifications:

 

  • The website has “dropped”;
  • The website is still “down”;
  • The website “rose

 

The “dropped” and “rose” are clear. The notifications “site is still down” are sent at each test fail, but only at the confirmed drops. The fails confirmation algorithm was described in the article “False alerts exclusion”

 

For each site-contact pair you may enable or disable the appropriate notification type. The setting can be located in the contact properties as well as in the general “matrix” at the “Notifications subscribtion” page.

Escalation and the notifications detalization level.

Suppose, two people are responsible for the site:

  • Administrator
  • Manager

 

Let's try to implement the following scenario:

 

  • In the event of a “drop” we want to send an email message to the administrator immediately;
  • If the site does not rise within 15 minutes, we send an SMS to the administrator;
  • If the site is “down” for more than an hour, then we send an SMS to the manager.

 

Adding the contacts for the users. While adding, draw attention to the “Notification Delay” window.

 

We appear to have three contacts with the following delays:

  • Administrator (email) – no delay;
  • Administrator (SMS) – 15 minutes delay;
  • Manager (SMS) – 1 hour delay.

 

According to this configuration the administrator will get all the failures notifications to the email, but SMS notifications will be sent only if the site is “down” for more then 15 minutes. The manager will receive only SMS about major failures lasting more than an hour. Setting up the contact working schedule

 

Suppose that one administrator can not cope, and we hired one more administrator. The first one works during the first half of the week, the second one works during the second half. Accordingly the notifications should be sent to the administrator “on duty” To set this scenario the window “Set the contact working hours” is used in the contact settings.

In this case the first administrator will receive the SMS notifications from Monday to Thursday inclusive. Additionally, you may divide the notification for different employees according to the time of day, for example appointing day and night administrators.

Conclusions: with the help of relatively simple mechanisms we may cover most notifications fine-tune user scenarios.

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Home > Blog > HostTracker_under_Azure
Those, who actively involved with the Web, should know Host Tracker, a company from Ukraine, which has been supporting one of the leading global web monitoring services since 2004. Its goal is to monitor site health and accessibility in near-real-time access. Using alert message system, Host Tracker allows to reduce downtimes, to improve quality of service for users, to quickly localize troubles...
Those, who actively involved with the Web, should know Host Tracker, a company from Ukraine, which has been supporting one of the leading global web monitoring services since 2004. Its goal is to monitor site health and accessibility in near-real-time access. Using alert message system, Host Tracker allows to reduce downtimes, to improve quality of service for users, to quickly localize troubles, and etc.
Architecturally, Host Tracker includes a server-based hub, acting both as a data collector and control center, and a series of software agents, launched in various regions – typically using the equipment operated by major providers, hosters and affiliates. The geographically distributed architecture provides common system reliability and also allows collecting data in terms of access speed, bandwidth and other key performance characteristics on regional level – a critically important feature for the international business.
The first version of Host Tracker, which is still functioning and providing services for tens of thousands of customers, was Linux based. Today, it is supported by nine control servers, located and organized in two DPCs on collocation principle, and few dozens of agents. Considering that the final objective of web monitoring is focused on increasing the uptime of client-based web resources – whereas 95% of Host Tracker customers were able to increase it up to 99% – then, performance and accessibility of the service itself are not just critical, but rather fundamental parameters that influence the whole business. Theoretically, Host Tracker should demonstrate accessibility close to 100%. However, an extensive growth of the service made this task hard to solve.
Host Tracker was facing constantly increasing network traffic – a problem for seamless operation of the service. Inability to add new control servers on-the-fly, difficulties when maintaining not uniform and multiple-aged hardware was another limiting factor. Moreover, the desire to develop the service through wider protocol and network service support was meeting certain obstacles. “Unfortunately, for Linux there was a limited choice of ready-to-use solutions and libraries, while inventing something completely new was difficult”, says Artem Prisyazhnyuk, Host Tracker director. “We had an idea of reviewing the stack of technologies we used for a more sophisticated one and after taking a closer look at the .NET platform, its potential in terms of scalability and network support, I realized that was exactly the thing we had been looking for.”
It was sure that migrating to a completely different platform should be a complex task – the project extended over three years. However, it was like blessing in disguise: during this period, the world has seen the cloud computing that seemed an ideal tool for solving both the scalability problem and putting aside one’s own whole infrastructure. Besides, the PaaS model allowed to remove most of the effort in terms of administering the solution and to control the application as a self-contained entity, to the extent of complete automation, and thus, Windows Azure had in fact no alternatives.
As a result, the second version of Host Tracker, commercial operation of which started in May 2012, is already functioning under Windows Azure. Its central ingredient is realized as Web Role and associated with SQL Azure Database – it provides external portal, analytics and report generation, control of monitoring applications. The latter are ensured with instances of Worker Role, which also use SQL Azure Database to store their data and to provide the service scalability depending on the network loading. Agents are functioning as they did before, with the viability of their transfer to Windows Azure being considered.
Now, Host Tracker uses HTTP/HTTPS and ICMP protocols to monitor specific ports, including various methods (HEAD/POST/GET), and etc.



Alarm reporting is available via email, SMS and instant messages. The customer can receive reports with statistics about resources being controlled and their performances. You can spend only 6 minutes to make monitoring settings for five sites, while the average response time in case of failure is limited by a couple of minutes, and it takes 1-3 minutes more to inform the customer about the problem. Using this service, anyone can check any site, including access from various regions.
As a result, if on the one side the transfer to the .NET platform itself gave us the potential to modernize Host Tracker, to optimize the application architecture and realize new internal functions, then, on the other side, the migration to the cloud allowed to refuse from less important, though time consuming activities such as administering the solution, and, first of all, to reach necessary performance indicators. Microsoft, for all basic Windows Azure services, declares 99,9% accessibility and guarantees monthly refunds, should this indicator be lower. This creates a firm ground for operating such services like Host Tracker, as the accessibility is the most critical parameter for these applications. Using the cloud infrastructure also provides a better protection for the service: unauthorized access to the application and many types of attacks are effectively excluded, while the data safety is ensured by triple reservation.  
Host Tracker received another advantage from abandoning its own infrastructure. The service’s performance characteristics are also rather critical, for they directly affect the failure reporting system operation. In this respect, Windows Azure is virtually a drainless source of computing power. This means that by timely starting additional monitoring instances you can support Host Tracker functioning parameters on the necessary level. Moreover, the cloud environment is exactly what you need in order to make this process almost fully automatic, excluding further need for direct control.
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