Administration Section
What would you feel if one fine summer day the data center with your equipment looked like this? Hello everyone! My name is Dmitry Samsonov, and I work as a lead system administrator at "Odnoklassniki." In the photo is one of the four data centers housing the equipment servicing our project. Behind these walls, there are about 4,000 units: servers, systems […]
Decoding the 2015 report by Ilya Kosmodemyansky titled "Linux tuning to improve PostgreSQL performance" Disclaimer: I should note that this report is dated November 2015 ā more than 4 years have passed and much time has gone by. The version considered in the report, 9.4, is no longer supported. In the past 4 years, 5 new releases of PostgreSQL have come out and 15 kernel versions of Linux. If we rewrite […]
If you work with Kubernetes, then kubectl is likely one of your most used tools. Whenever you spend a lot of time working with a specific tool, it makes sense to study it well and learn how to use it effectively. The Kubernetes aaS team from Mail.ru has translated an article by Daniel Weibel where you will find tips and tricks for efficient work […]
BLE Under the Microscope (ATTs and GATTsā¦) Part 1, Overview It has been quite some time since the first specification for Bluetooth 4.0 was released. Although the topic of BLE is very interesting, it still deters many developers due to its complexity. In my previous articles, I mainly focused on the very low-level Link Layer and Physical Layer. […]
In projects related to microservice architecture development, CI/CD transitions from a pleasant option to a pressing necessity. Automated testing is an integral part of continuous integration, and a smart approach to it can offer the team many enjoyable evenings with family and friends. Otherwise, the project risks never being completed. You can cover the entire microservice code with unit tests […]
I am publishing the first chapter of lectures on the theory of automatic control, after which your life will never be the same. The lectures for the course "Control of Technical Systems" are delivered by Oleg Stepanovich Kozlov at the department of "Nuclear Reactors and Energy Installations" of the Faculty of "Energy Machine Engineering" at Bauman Moscow State Technical University. He deserves great gratitude for this. These lectures are being prepared for publication as a book, and […]
It has been barely 10 years since the RoS developers (in stable 6.47) added functionality that allows DNS requests to be redirected according to specific rules. Previously, one had to convolute with Layer-7 rules in the firewall, but now it's done simply and elegantly: /ip dns static add forward-to=192.168.88.3 regexp=».*\.test1\.localdomain» type=FWD add forward-to=192.168.88.56 regexp=».*\.test2\.localdomain» type=FWD My happiness knows no bounds! […]
In this article, we will explore the progression not just of a machine, but of an entire mini-laboratory from the HackTheBox platform. As stated in the description, P.O.O. is designed to test skills at all stages of attacks within a small Active Directory environment. The goal is to compromise the available host, escalate privileges, and ultimately compromise the entire domain while collecting 5 flags. Connection […]
Today we share a selection of administration courses from the Education section on Habr Career. There are, to be honest, not many free options in this field, but we have managed to find 14 of them. These courses and video tutorials will help you acquire or enhance skills in cybersecurity and system administration. And if youāve seen something interesting thatās not included in this issue ā share the links […]
Remote learning is becoming increasingly popular for all the reasons we understand. While many Habr readers are familiar with various courses in digital specialties ā software development, design, product management, etc. ā the situation with lessons for the younger generation is somewhat different. There are many services for online lessons, but which one to choose? In February, I evaluated different platforms, and […]
Kubernetes is an excellent tool for running Docker containers in a clustered production environment. However, there are tasks that Kubernetes cannot address. With frequent deployment in a working environment, we need fully automated Blue/Green deployment to avoid downtime in this process, which also requires handling external HTTP requests and performing SSL offloading. This necessitates integration […]
When creating my own backup management methodology across multiple MS-SQL servers, I spent a lot of time learning the mechanism for passing values in PowerShell during remote calls, so I'm writing this reminder for myself in case it might be useful to someone else. So, let's start with a simple script and run it locally: $exitcode = $args[0] Write-Host 'Out to host.' Write-Output 'Out to […]