Developers Club geek daily blog

How to cover with monitoring all layers of infrastructure

1 year, 8 months ago
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Somehow I considered that 1 minute of idle time of hh.ru on weekdays affects about 30 000 users in the afternoon. We constantly solve a problem of decrease in number of incidents and their duration. We can reduce quantity of problems the correct infrastructure, architecture of the application is a separate subject, we will not take it in attention yet. Let's talk better about how quickly to understand what occurs in our infrastructure. Here just we are also helped by monitoring.

In this article on the example of hh.ru I will tell and I will show how to cover with monitoring all layers of infrastructure:
  • metrics client-side
  • metrics from frontends (nginx log)
  • network (that can be got from TCP)
  • application (log)
  • database metrics (postgresql in our case)
  • operating system (cpu usage can be useful too)

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Boris Wolfson's master class. Agile bases

1 year, 8 months ago
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This post is written based on Boris Wolfson's master class (the director of development of HeadHunter) devoted (a surprise!) to Agile bases. Material will be useful to all, someone is not familiar with this methodology of development of difficult software at all, or has a vague idea of it.

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As we won against a twilight between testing and operation

1 year, 8 months ago
Some time ago we in HeadHunter found "a twilight zone" by transfer of the new version of the website from testing in operation. The insufficient attention to a difference between test and fighting infrastructure periodically led to falling of the website.

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Old test stands considerably differed on the internal device from a working cluster. Init-scripts for start of services differed, files of a configuration on an arrangement and contents differed. Interaction of services among themselves happened without features of a fighting environment.

I will show logic of our solution which allowed to achieve qualitatively new results of testing.

This article continues my report on SQA Days-18.

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Two problems of HeadHunter on Data Science Week: try to solve

1 year, 10 months ago
At the end of August after series of free lectures on Data Science Week 2015, dataton (datathon) – competition where programming teams and analysts were solved by business challenges from the Data Science area.

On the datatena there were three tasks two of which has prepared the HeadHunter team and one company OZON. It was, at once I will tell, not the simplest task because the most part of our data is confidential. Nobody will want that programmers and analysts practised on real summaries or the closed data on vacancies. But all of us have collected something. For check of results organizers have thought up metrics and cheker have written. And these children have won on the datatena:



Directly here and now I suggest you to test the strength and to solve three problems with which children fought on the datatena. Chekera for check and all files I apply.

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School of the HeadHunter programmers — we open set 2015/16

1 year, 10 months ago
Школа программистов

September — the beginning of academic year not only at schools and universities. HeadHunter in next (already the sixth!) time declares set in School of programmers. This year, as well as in previous, we will prepare full-stack of the developers ready to all calls of modern web development.

Training will take place two times a week in the Moscow office of HeadHunter near the subway Alekseevskaya in the evening. For receipt in school it is necessary to fill in the questionnaire on the site and to pass small test. We will send to the candidates who have passed this stage additional tasks by results of which we will invite you to interview.

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Introduction to the analysis of social networks on the example of VK API

1 year, 11 months ago

Data of social networks — inexhaustible source research and business opportunities. On the example of VKontakte of API and the Python language we will sort couple of practical examples today, kotor will help to learn:
  • work elements with Python — networkx library;
  • how to address to VKontakte of API from the Python language by means of standard libraries, in particular, to receive the list of friends and members of groups;
  • some opportunities of the Gephi program.

Disclaimer: this article does not apply for any novelty, and only pursues the aim to help the interested to collect the strength and to start realizing the ideas.

(hair sphere for drawing attention)

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As I have learned to do the world better in HeadHunter

2 years, 2 months ago
Before I have come to HeadHunter, I did not know that such code review. I knew, what such code approval? so was in one American company where I began the career and where all code passed in the project before wise eyes of professor Fortran behind little table in the depth of office. He with fatherlike smile looked at my first steps in development and spoke:? Here correct, please, and you can let out?.



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Starts set in school of the HeadHunter 2014 programmers

2 years, 11 months ago
Today the fifth annual set in school of the HeadHunter programmers for season 2014-2015 has opened new, already. During the first part of training of students wait for lecture of our specialists, and during the second children will have opportunity to apply knowledge in team development of own projects. Occupations will take place from November to May, 2015 on weekdays in the evenings in the Moscow office of technical department HeadHunter near metro station? Alekseevskaya?.

This year the program of training covers all stack of the technologies used at us: beginning from Java and Python and finishing JavaScript and XSLT. In the second part of training students will monthly get grant of 15 thousand rubles, and the best students will receive the invitation to join our team.

Receipt consists of three simple stages: it is necessary to fill in the questionnaire, to perform test task for Java or Python and to have internal interview.


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Similar search queries in hh.ru

3 years ago
Most of large searchers and services has mechanism of similar search queries when to the user the options thematically close are offered that he looked for. So do in google, yandex, bing, amazon, a few days ago it has appeared and at us on hh.ru!



In this article I will tell how we got similar search queries from site hh.ru logs.

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The most operable, responsible and sociable

3 years, 1 month ago
A few days ago children from service of the researches HeadHunter have decided to have a good time a little and have looked who in the world of IT considers himself as the most responsible, sociable, operable, fast-trained and independent. In other words, who is not confused to use these popular, capacious, informative and? so loved by recruiters? characteristics in the summary.

For comparison we have taken the list of professions which names employers most often enter by search of the summary in the field of information technologies. 87,5 thousand summaries placed or updated in the first half of the year are analyzed.

Important, from edition: what people speak or is not told about itself in the summary? not always means that they such or not such actually.

Testers and business analysts speak about the responsibility in the summary twice more often than the java and C programmers ++. Perhaps, they consider, what in their profession these qualities are more priority?



And how affairs with skill to communicate are?

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