Content Check
Content CheckContent check is a way to check the presence of specific info on the page.
Content Check Content check is a way to check the presence of specific info on the page.

Content check is a way to check the presence/absence of specific info on the page. It helps to check not just the page itself for accessibility, but the performance of the site too. It is useful for sites with complicated structure - which contain many scripts and data that is stored in database or other off-site storages. In this case, there is possible cases when the page itself is working fine while some of the linked resources are not available - thus, some info on the page is missed.

HostTracker provides tools to solve this problem. You may create ContentCheck task and provide specific keywords for monitoring:

There are several important things on that screen:

Content Check - set of comma-separated keywords to look for.
Advanced Content Check option - useful for immediate detection of the reasons of a problem. In case of appearance of the keyword, the phrase, previous to the keyword, is sent you as the result of the check. For example, you enter keyword exception and select this option. Somehow, on the page appears the statement: Wrong SQL statement on the line 123 exception. In this case, you get an alert saying Wrong SQL statement on the line 123.
Conditions Field - allows to specify conditions for set of keywords. You may set to detect an error in case of presence/absence of all entered keywords, or just any of them.

For monitoring the presence of images, videos, execution scripts - you may choose a keyword from their description, or add a special short script which will return Error or other keyword if something is missed.

Restrictions:
Only first 10 Kb of page are analysed
Only first 120 characters of each line are analysed

  • CM.Glossary.Uptime
  • CM.Glossary.WebsiteMonitoring
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"

Service is very  reliable and performs as described in sales information.  User interface is simple and easy to use.

"
- St
Why do we need monitoring? The overview of the HostTracker service. Part 1

Why there is a need in monitoring? How the monitoring could help in the sites and servers development and testing? This review will answer to these questions and will also show how the simple desire to optimize your work may be transformed into a useful product for others, as well as, how not to lose the ‘startup spirit’ and always keep up with your clients.

HostTracker Company is one of the market leaders in the supplying of monitoring services for sites and various web services. It teems with a wealth of different constantly improved tools, which are taking into accounts the most recent tendencies and trends. How did this company emerge? Why there is a need in monitoring? How the monitoring could help in the sites and servers development and testing? This review will answer to these questions and will also show how the simple desire to optimize your work may be transformed into a useful product for others, as well as, how not to lose the ‘startup spirit’ and always keep up with your clients.

Introduction or the history of startup

Everyone involved in the IT sector must know the feeling, when a server (website, database, software, network) seems to be perfectly configured, but it suddenly stops to work properly. Solving this problem could take a lot of time. Meanwhile, this mess would go on, take place regularly or wouldn’t happen at all – but, nevertheless, that’s the worst, as it wouldn’t be clear when it shows up another time. Moreover, what if this happens during handover the project to the client? Pondering over all these things caused HostTracker to appear.

A founder had always tried to make his work on objects as brilliant as he could at his main job, so he decided to automatize the process of monitoring. If at that time (at the beginning of 2000), there were reliably working monitoring services – possibly, HostTracker would never have appeared. Therefore, he had to write a simple script to check his bulk of sites. However, the script faced the same problems that were mentioned at the beginning of this paragraph. From time to time, the script didn’t work at all or didn’t work properly.

So, that’s why, we had to optimize the script a little and make it more reliable, as well as, through the duplication and distribution it on several machines. After a series of optimizations the idea crossed our minds that it could be useful for someone else, and HostTracker became public. With the advent of a variety of clients – we decided to monetize the efforts. As you can see, our service appeared to solve personal problems, but during the process of development has become available to others to help them solve the same problems, which, at one time, we faced.

Monitoring: the main points

This part of the review contains information about the most popular feature - regular check of the site or other entity available from the network for immediate identification of emerging problems. These checks can be run on different protocols: http (s), icmp (aka Ping), port (check any port over TCP) etc. It is worth noting, that there are different approaches to monitoring. There is an internal monitoring - when the state of the site is estimated by the software hosted on the same server. To put it tentatively, there may be included such tools like Google Analytics– built in the page script sends information about customers who entered the site, and can make indirect conclusions about the site performance. The other type of monitoring - external, or, as lawyers say, "monitoring by a third party." It is embodied in simulating the logging in of real users with real addresses to the site, and making conclusions on the real server replies to the sent requests. Further we will talk about this method in the review.

Infrastructure or how it works

For easier understanding, the infrastructure can be divided into two components: the "internal" and "external". The “internal” is placed in the cloud and consists of computing servers, databases, file servers etc. All of these components belong to HostTracker and are operated directly by HostTracker employees. The “external” component - nodes or agents, which are placed around the world and serve as independent servers inspectors, similarly to "Secret shoppers" at the stores. They are testing the sites and other entities by creating the standard requests for checking protocol. If it is a web site test, then it will be the usual http requests and there will be no difference between these requests and requests of real visitors.

These servers are completely independent from each other and from internal system structure. Everything what they do – receive a list of sites for checking from the central server and give it back the check results. Some of these servers are being rented by the HostTracker, whilst the majority of them belongs to the partners. These partners are providing them for free or with a significant discount, in return for backlinks or discounts for our services, or just due to friendship relationship.

This kind of infrastructure allocation is a result of monitoring service performance algorithm.

The service performance algorithm

Regular checks are being done due to the client’s predefined interval, beginning from one minute. When it comes to testing, the server sends the task to one randomly selected agent – a part of the external HostTracker network. It is performing checks by a given protocol, and sending back the response of the checking server. These results are being processed on the “external” side. If it happens to have a positive response - nothing happens, there will be only a record in the database about this (it is available to the client in a form of an inspections log). If an error has been noticed, then tasks are immediately created to verify, again, this site by other randomly selected servers from the general network. After that, the answers from all these servers will be analyzed.

If the error hasn’t been confirmed by the majority of servers - it remains in the log and there is no reason to worry. Apparently, anything can happen: the network lag, requests overload and everything. If most or all of the agents do confirm an error - then it is assumed, that the trouble occurred and there is a serious problem – likely, at that time, a lot of people can’t get to the site. Moreover, almost all commercial sites will suffer from a great loss of money in this situation.

Error handling and clients notification

According to the settings, after identifying the problems, a lot of different things can also happen. The problem initial diagnostics is being done at once. If there is any error, the code of this error is recorded, otherwise there will be a record of the protocol response. This data can be used for detecting the reasons of the error, for example, network failure, server failure etc. However, first and foremost, the client is interested in getting to know about the problem. So, if you want to be aware of any errors at any time, you should register your phone number, e-mail or other communication channel to receive notifications from HostTracker.

These notifications may be sent to different people, with different contacts and at any time. Truly, a lot of interesting features are there to offer. The message can be sent immediately, which is done the most frequently. Although, that’s not enough for the particular customer to be satisfied. Firstly, the "unimportant" sites do exist and it would be inappropriate to wake administrator up because of the short-term downtime. Secondly, there are "important" people, that shouldn’t be bothered because of different insignificant problems. Therefore, HostTracker offers a feature of the alerts escalation. As well as, HostTracker would send a notification to a specific address after some time of the site’s fall, if it didn’t recover by itself.

Moreover, you can create "work schedule" for each contract - set the time interval during which, it is possible to send alerts. So, HostTracker wouldn’t disturb this person at other time. It happens to be very useful for some customers. For instance, this configuration will send an alert to the particular person between 8:00 am. and 7:00 pm., in case the site has been “off” for one or more hours:

We will describe a wide variety of other service functions in the next reviews. Also, you will find all histories of their emergence and development, the examples of their usage and other things from our own experience. It is worth noting, that one of the main advantages of the service is the orientation to clients. Many service functions have been invented due to clients, friends and partners requests, enabling them to solve their specific technical problems, the solution of which on their own would require a lot more resources. Therefore, we’re looking forward to your feedbacks and suggestions!

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Home > Glossary
Active Monitoring
Active Monitoring Active Monitoring is the way to check the site performance by simulation of visiting by real users.

Active Monitoring is the way to check the site performance by simulation of visiting by real users. It is done by external service, usually with distribyted networks. The checking servers create the requests like the real clients, who are trying to download a web page. Doing it on regular schedule, allows to check if the page is available from the web. If not - there is a possibility to catch and report the error. The difference between the bot and a real person is visible only for bulky pages with lots of content - in order to save the traffic, monitoring systems usually download only a part of such pages, which is enough to make sure the site is Ok.

Active monitoring is an independent eye on your site. The checking is not connected to your company and web hosting, and so provides the clear third-party view of the situation. HostTracker service uses active monitoring to supervise web sites.

  • CM.Glossary.WebsiteMonitoring
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Availability
Availability Availability of a site shows if a site is accessible from the Internet.

Availability of a site shows if a site is accessible from the Internet. This term is also about access to a server, database or another entity. As all objects in the Internet are based on comlicated infrastructure, nothing can be available always. The question is how to measure it, what is normal and if we may affect it anyway. The measurement of availability is connected to terms Uptime and Downtime, which show for how long a site is unavailable. However, these values can not create the full view of the situation. There could be many reasons of unavailability - server or connection problems, application error, overload of the site and so on. To avoid or shorter the failures, it is needed to supervise the site and analyze the errors, if they happen. For these purposes there are special monitoring tools, which help to increase to availability of the site, collect statistics and provide necessary information about the errors for fast repair. These tools are called Website Monitoring services.

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Content Check
Content CheckContent check is a way to check the presence of specific info on the page.
Content Check Content check is a way to check the presence of specific info on the page.

Content check is a way to check the presence/absence of specific info on the page. It helps to check not just the page itself for accessibility, but the performance of the site too. It is useful for sites with complicated structure - which contain many scripts and data that is stored in database or other off-site storages. In this case, there is possible cases when the page itself is working fine while some of the linked resources are not available - thus, some info on the page is missed.

HostTracker provides tools to solve this problem. You may create ContentCheck task and provide specific keywords for monitoring:

There are several important things on that screen:

Content Check - set of comma-separated keywords to look for.
Advanced Content Check option - useful for immediate detection of the reasons of a problem. In case of appearance of the keyword, the phrase, previous to the keyword, is sent you as the result of the check. For example, you enter keyword exception and select this option. Somehow, on the page appears the statement: Wrong SQL statement on the line 123 exception. In this case, you get an alert saying Wrong SQL statement on the line 123.
Conditions Field - allows to specify conditions for set of keywords. You may set to detect an error in case of presence/absence of all entered keywords, or just any of them.

For monitoring the presence of images, videos, execution scripts - you may choose a keyword from their description, or add a special short script which will return Error or other keyword if something is missed.

Restrictions:
Only first 10 Kb of page are analysed
Only first 120 characters of each line are analysed

  • CM.Glossary.Uptime
  • CM.Glossary.WebsiteMonitoring
  • CM.Glossary.Uptime
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Database Monitoring
Database monitoring Database monitoring - DB check for access and regular execution of the specified query.

Database monitoring feature allows to run a query during every check and react in the appropriate way on the result. Also, it is possible to check just possibility to connect to DB - by ignoring the query field. To set the monitoring, fill the connection data: DB server address, port, database name, login and password of a user for connection. We strongly recommend to create the new user with limited rights. However, do not forget to provide him enough rights for performing the supposed actions. Also, it is necessary to add HostTracker servers addresses, to the whitelists on firewall or other blocking software, to allow the access. The addresses are permanent, and are listed on the same form.

Create ContentCheck Task

There could be arbitrary query - SELECT, UPDATE, DELETE, INSERT, execution of stored procedures (like scheduler), results comparison, logical operations. The only restriction is execution time - it should not take longer than 30 seconds. Otherwise, the timeout error will be reported.

It is recommended to create the queries which display the necessary value in the first row of the first column. This result can be analysed. For UPDATE, INSERT, DELETE queries the number of affected rows is analysed. There are different ways to analyse the resulted value by comparison with specific preset - equal/not equal/higher/lower/in range. In case the condition is not satisfied, no connection to DB, query timeout - the error is reported.

Create ContentCheck Task
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Distributed Monitoring
Distributed Monitoring Distributed monitoring is a method of website monitoring when the checking is performed from several locations.

Distributed monitoring is a method of website monitoring when the checking is performed from several locations. The main purpose for this is to exclude errors of checking server (which is always possible) from the site statistic and provide more precise result. Usually it is realized through the network of independent servers which check the sites one-by-one or simultaneously. The advangtages of such checks are listed below:

Checks are happening from different locations, just like the real users do.

If a single check fails - others may prove or decline the failure. So, probability of false downtimes is really low.

It is possible to overview the access and download speed from different countries and cities.

Possibility to catch network-related or DNS problems: site might be visible from your computer, but are you sure it works for everyone?

  • CM.Glossary.WebsiteMonitoring
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DNS
DNS DNS - domain name system, a system for locating a web site.

DNS - domain name system. This system helps to find a real server by virtual site name. The system is realized by the hierarchy of DNS servers, each of them holds information about specific domains and may delegate such role to lower stage servers. Let's take, for example, site www.host-tracker.com. The upper domain is .com, so the request is made to the server, which is responsible for all .com sites. It knows where each site is located, or at least, where is another server, which knows for sure. If you get "Server not found" message, that means no record exists on the DNS server for the site name you've requested.

Each time you enter an address into the browser - a DNS request is made, in order to find where the site is located. To make this process faster, DNS data can be saved into a cache. If you own a site and decide to change its name for some reason, or if you have just created the new one - you should keep in mind that DNS cache needs some time to be updated globally. Usually, it happens within couple of hours, but it can take up to 48 hours. That's why sometimes a newly-hosted site can not be visible for some time.

  • CM.Glossary.WebsiteMonitoring
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Downtime
Downtime Downtime is when your site does not work. It's really bad.

Downtime is when your site does not work. If the site does not work - you'll not get any benefits from its existence. Downtime is opposite to uptime. There could be various reasons why a site does not work. Most usual cases: problems with server, server overload, application error, network problems and so on. The first step of fixing en error is detecting. There are special instruments, called website monitoring services, which may check sites for errors over the time. Such tools help you to detect error and provide primary analysis of its reasons. Also, usually some information could be found in server logs. If you have access to them, you should review. If not - ask your hosting company to provide them. Detecting of errors may help you to evaluate the reliability of your site and hosting.

  • CM.Glossary.WebsiteMonitoring
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HTTP
HTTP HTTP - hyper text transfer protocol, a way to transfer website data via Internet.

HTTP - hyper text transfer protocol, a way to transfer website data via Internet. At first, was created for transfer of HTML documents, now most of website data (audio, video, images etc.) is downloaded through this protocol. HTTP has several methods - to check a website, to get the data from the server, and to upload some information from client to the site. More about them you may find in this article. HTTP has its secure version - HTTPS

This protocol is used by clients to review web pages. Thus, to check a website, we should use it too. Website monitoring services, like HostTracker, perform HTTP checks to make sure that the site is operating well.

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HTTP methods
HTTP methods HTTP methods define actions, wished to perform to a specific site.

GET method is used when the page is loaded from server to your browser. If it works, your web page is available to load. It is the most common method among all, when you type a site address in your broswer - this method is used to show you the site content.

HEAD method is similar with GET, but it load from server only headers of your page. It is useful if You want to test just accessibility of a web page or review its headers.

POST method is used to send information from you to server. If a page includes text field(s) for filling, POST method is used when you click button "submit" (or whatever is name of that button). It brings information you have typed into those fields to server. So, if there are some text fields on your page, you can use this method. If it works, your web page is available to use, and text, typed into fields on your page, is able to be transferred to the server. An example of using POST method for Website Monitoring is provided in this article (You provide specific keywords, which are inserted into text fields).

  • CM.Glossary.WebsiteMonitoring
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Passive Monitoring
Passive Monitoring Passive Monitoring is the way to check the site performance by server-side software.

Passive Monitoring is the way to check the site performance by server-side software. It can create the exact copy of incoming traffic for analysis, or it can operate on real traffic. Passive monitoring may collect statistics and watch over some important values, like traffic consumption, number of visitors etc. Also it is handy to analyze the real workflow on your site. However, only server-side errors could be caught. If case of broken Іnternet connection or other Internet-related errors, passive monitoring fails - as it shows only the server performance which is Ok. You'll notice the the lack of visitors, but this fact does not appear immediately. And this is the main difference between the Passive Monitoring (server-side) and Active Monitoring (third-party).

  • CM.Glossary.WebsiteMonitoring
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Ping (ICMP)
Ping (ICMP) Ping is request message for protocol ICMP.

Ping is request message for ICMP (stands for Internet Control Message Protocol). This protocol is used by different network devices to check if a service or a device is available. Usually it is used for network diagnostics.

Ping monitoring allows you to keep an eye on your network infrastructure. Ping failure means broken connection to a network entity. It is handy to use Ping together with HTTP monitoring. In this case, you get additional information - for example, you know if the error is site-related, or the whole server has gone down. However, sometimes ICMP could be blocked for incoming requests, in order to prevent ddos attacks.

  • CM.Glossary.WebsiteMonitoring
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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.

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Quick Start Guide
Quick Start GuideStart using HostTracker in 5 minutes

1. SignUp and fill the Profile

2. Enter your sites for checking
Create monitoring task

3. Set monitoring parameters
Set monitoring parameters

4. Register contacts for alerts and reports
Create contact for alerts and reports

5. Subscribe for alerts
Subscribe for alerts

6. Subscribe for reports
Subscribe for reports

7. When the Free Trial expires, subscribe to a permanent package
Upgrade your account

In case of any questions, write us to ht2support@host-tracker.com

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Response Time Monitoring
Response time monitoring Response time monitoring is testing how fast is your site.

Response time monitoring is testing how fast is your site. It might be accessible, but bad performance can still make it unattractive for the clients. The monitoring of the response time allows you to check how the site acts as the time goes on. Do any of the scheduled tasks, like backup, updates etc affect the performance? Does the site works well for the whole world, or some regions of interest could meet a confusing delay?

HostTracker provides a possibility to check the reaction of your site. Select Response time check on the main screen:

Create ContentCheck Task

Then, select the largest satisfactory response time for the site. Is this value is exceeded, you receive a notification. Also, all the statistics is stored in the check log, and response graph is generated. You may check this data at anytime.

Create ContentCheck Task

NOTE! Response time depends on the distance between the datacenter of your site and our checking server. It might be large enough for a remote country. To decrease this effect, select a checking region in advanced options.

Create ContentCheck Task
  • CM.Glossary.WebsiteMonitoring
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Uptime
Uptime Uptime is the period of time when a site performs well.

Uptime corresponds to the time when a site is accessible from the Internet. The opposite term - downtime - shows for how long a site has not been working during specified period of time. Usually uptime is measured in percents, and for period of time is choosen year. Percents over the year could be easily transformed into time values. Some typical values of uptime and corresponding period of unavailability during the year are shown here:

90% - 876 hours

99% - 87 hours, 36 minutes

99.9% - 8 hours, 45 minutes, 36 seconds

99.99% - 52 minutes, 34 seconds

So high uptime is really important. Even if it seems that 99% is pretty high value - it corresponds to several days of failure. If that happens in a row, many clients can be lost. Uptime value is usually guaranteed by web hosting, where the site is hosted. Website Monitoring may help you to increase the uptime and check if the value, declared by the hosting company, is real.

  • CM.Glossary.WebsiteMonitoring
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Web Hosting
Web Hosting Web Hosting is a service which makes a site available from the Internet.

Web Hosting is a service which makes a site available from the Internet. It provides a physical place for your site (server) and Internet connection, also it may provide DNS services. Hosting companies differs from those who own huge datacenters to the small ones who rent couple of servers somewhere.

How to choose a hosting? You should pay attention to several important things: features, price, support and uptime.

Features include disk space, database usage, bandwidth, monthly traffic etc. Requirements totally depend on your site. It is clear that personal page has different requirements than a well-known online market.

Price. You may even find completely free hosting, just look if the service satisfies your needs.

Support. How long does it take to solve a problem with your site? What is an avarage response time? Your site is down for a week, and noone cares - is that possible?

Uptime - what is actual running time of the site.

Reliable hosting is very important for business. Using website monitoring services may help to evaluate the hosting service and check how often do the problems really appear.

  • CM.Glossary.Uptime
  • CM.Glossary.Downtime
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Website
Website Website is a basic unit of information in the Internet.

Website is a single resource of information in the Internet. Usually, it is realized through a set of web pages, devoted to some specific topic. The pages are written in special markup lenguages and may contain various types of data - applications, audio and video files, images etc. The site is hosted on a hardware server and can be found in the Internet by unique name due to DNS. The access to a website usually provided by HTTP (hyper text transfer protocol), or its secure version - HTTPS. This protocol provides possibility to deliver information from the server to a client, who is usually viewing the pages with the help of special application, called browser.

  • CM.Glossary.Uptime
  • CM.Glossary.Website Hosting
  • CM.Glossary.DNS
  • CM.Glossary.HTTP
  • CM.Glossary.WebsiteMonitoring
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Website monitoring
Website monitoring Website monitoring is an automated process of checking availability of a site.

Website monitoring is an automated process of checking availability of a site. The main goal of it is evaluation of possibility to access the site by clients. It is clear, that a site is efficient when an interested person can load the page and make a purchase or look for some information. If this action fails for some reason - the site does not execute its mission, and a client will find what he needs somewhere else.

There are many solutions of this problems, and all of them could be divided into passive and active ways. The result of monitoring is the value of uptime, measured with some accuracy. Having it, one can conclude how long is the site broken during some period of time (usually, for a year). Low uptime usually means that the server where the site is hosted, or internet connection to it, is unreliable and is required to be changed.

  • CM.Glossary.Uptime
  • CM.Glossary.Downtime
  • CM.Glossary.ActiveMonitoring
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