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
  • CM.Glossary.WebsiteMonitoring
  • CM.Glossary.ContentCheck
more glossary
"

Very usefull service, helps us to monitor activity of our sites.

"
- A.
What could we check by using the cloud services? Part 2

  In the beginning, HostTracker company was founded on the basis of a simple website to provide free customer services. Though, a few years later, this startup developed a wide variety of tools serving to solve various problems, including different network issues. In a series of publications, we have decided to describe thoroughly all the features of our service, also to share our experience in the development of such projects with you and to mention interesting challenges that we faced. 

In the beginning, HostTracker company was founded on the basis of a simple website to provide free customer services. Though, a few years later, this startup developed a wide variety of tools serving to solve various problems, including different network issues. In a series of publications, we have decided to describe thoroughly all the features of our service, also to share our experience in the development of such projects with you and to mention interesting challenges that we faced. Moreover, for those seeking an example of how to sell something that had been made for themselves, our experience would be useful, as most of our features were developed due to our personal needs.

In the previous part of the review we have talked about the history of the service and the most basic functions - regular inspection of sites and servers, and what is more, notification of their efficiency. Before starting to describe more advanced features, we should write where do all these ideas come from and how to prioritize them. One of the key secrets often used by entrepreneurs is to follow the statement: all people are unique. All customers’ requests are unique, so you have to learn how to deal with them. Therefore the IT sector is utterly susceptible to this factor, as a great number of customers have profound knowledge and diverse experience. Nevertheless, part of the problems can be solved with available resources. However, the main feature of our work is that, frequently, we have to evolve something. Most of the HostTracker’s functions were developed or adapted due to the conveniences and needs of the particular people. We are also a part of that people, as having rather large infrastructure, and also need to have everything work properly. Therefore, we ourselves are the most picky client.


Precious little things

It worth noting, that in addition to different regular checks, there are other useful tools. They include monitoring of the domain and SSL certificate expiration time. This seems to be negligible, but could bring a lot of unexpected inconveniences to work. These functions appeared in HostTracker, when one of our personal domains had expired. Moreover, large companies also frequently face these problems, as the prolongation of the domain /certificate expiration time depends on the unreliable human factor. Therefore, a notification that the domain should be prolongated, is stored not only within spam folder (already overflowed with continuous marketing messages from your hosting company), but also to the folder with the data of website downs. As well as, the SMS notification capability still exists. That’s why these features are being so handy.

Another interesting feature is the domain check to see if they are blacklisted in DNS-based lists. These lists are independent and are generated separately using different algorithms. What is more, they were mainly created for filtering of the suspicious entities. Each administrator can configure own web server in different ways, for example, not to receive messages from the servers from a specific list. It helps fight off spam, malware spread, DDoS attacks and other problems. But all of these lists have their own algorithms, and there is no guarantee that in the result of any coincidences your website wouldn’t appear in any of these blacklists. Moreover, according to the statistics, this is happening on a regular basis with the most innocent sites. For example, no one can guarantee that a hacker wouldn’t use your nearby IP for different spam attacks. In this situation, the entire range of IPs would be considered as unreliable. What are the consequences of that?  Your messages wouldn’t be delivered to customers, the site wouldn’t be so easily found in search system and so on. Furthermore, you will find out this problem when the changes become critical or even irrevocable. Therefore, the monitoring and notification of DNSBL are also essential.

The content check

Here is a good example of how the usage of functions may exceed developers expectations. We have mentioned about several such cases earlier. Actually, nowadays a lot of things have a web interface whilst for others – it could be easily created, if needed. Therefore, it was developed not only the check function of whether the page was loaded completely using simple parsing, but also another mind-boggling things of this check. Adapting to different customer requests, this feature has become very flexible. It may look for one or plenty of words from the list at once. Moreover, it may detect the emergence of certain phrases. This feature may also raise as an error the whole line that contains the keyword. For instance, if there is a kind of server-status page (“Server 1 OK” etc.) and it shows “Error”, then the message will be “1 Server Error”.  In this case, all diagnostic is already done, and you can start troubleshooting immediately.

What if it happens, that the server should be down?

In addition to the notification of the failures of the sites, HostTracker provides another important function – gathers statistics of each examined site. When the various buttons on the sites were popular – HostTracker’s button also often appeared with the figures of website attendance, the weather forecasts and other things like that. Now it is possible to use a widget, but still the button is also available for retro fans. In addition, statistics is very important for managers. They constantly want to know whether the website and administration of it are working properly. Therefore, there is another useful function - the maintenance planning. Even the most stable sites and servers must be updated or rebooted from time to time. At the same time, it’s not the desired to lose so-called “9s” in terms of uptime. Planning of the maintenance let us achieve two goals (together or separately). This includes: not to send error notifications and not to record errors to the statistics during a specific span of time. Of course, it seems to be a kind of cheating, but outlined maintenances are justified, especially in excluded time. In addition to this, different verifications have being done and written to the log during maintenances. It can be useful for webmasters and administrators, as log let determine exactly the duration of updating or restarting processes, any occurred errors, other breakages etc. Moreover, thanks to that, the whole process of error emergence could be tracked: from the stage when the server wouldn’t be available for some time to the stage when the application would return an error.

Maintenance can be scheduled as a one-time job or on a regular basis. For example, if the backup is done every night, or a new release - every Thursday. The only condition is that the maintenance schedule should be made up at least 12 hours prior to the site/server nearest suspension period of time. This is done to ensure that all maintenances won’t be responsible for any pity unexpectancies, and statistics provided by HostTracker will be trustful.

A kind of an epilogue

We are frequently asked why we are doing this. The same things could be done without HostTracker’s help.  And you know what - definetely, they could. Especially, if you need only one tool. Many people are talking, that the whole Business World is built on human laziness. By solving routine problems, HostTracker provides a slice of work-free and responsibility-free time in the customer’s schedule. Truly, not everyone is able to assemble a car by himself. We look up to people, who are eager to create something good for personal needs in our field, but most people don’t want to spend their free time for doing something like that.

Additionally, our clients are: non-IT specialists; IT specialists who have to report something to their managers; managers themselves; fans of reliability – they use their own tools and take advantages of someone else’s; and many other groups of people.

All in all, we are always looking forward to your comments.

more blog
Thank you for feedback!
 
Sign In
Sign Up
Prices & packages
Our monitoring network
Home > Blog > part1

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!

Share:
Send to Twitter Send to Facebook Send to LinkedIn Share on Google+
Blogs:
HostTracker blog HostTracker page on Facebook