Andrej Yemelianov

Andrej Yemelianov

Technical Writer / Author of 23 articles

I write software documentation and articles. I translate complicated technical texts (at work) and poetry (for fun).

PipelineDB: Working with Data Streams

We’ve already touched on the issue of processing events in real time. Today, we’re going to return to this topic and talk about a fairly new and interesting tool: the streaming DBMS PipelineDB.

PipelineDB is built on and fully compatible with the PostgreSQL 9.4 codebase. It was first released in June 2015 and the enterprise version came out in January 2016.

Below, we’ll compare PipelineDB with similar solutions, give brief installation and initial setup instructions, and also look at a use case.

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Netdata: Monitoring in Real Time

In previous posts, we looked at various issues related to monitoring, collecting, and saving metrics and different methods and tools for getting around them. In today’s article, we’ll be discussing yet another tool that simplifies these processes: Netdata.
Unlike other analytical tools, Netdata is designed for gathering and visualizing metrics in real time (and when necessary, a backend can be incorporated for gathering and saving collected metrics).

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HTTP/2: Making the Switch

Last year marked a milestone in the world of Internet technology: the confirmation and standardization of HTTP/2. Popular web servers like Apache and Nginx already support HTTP/2, as do the latest versions of most browsers.

Data shows that by the middle of 2015, very few web sites and services had switched to HTTP/2, only 0.4%. The latest statistics (September 2016) show a significant increase: from 0.4 to 10%. It wouldn’t be that wild a prediction to say more and more sites are going to be making the switch and at a faster rate.

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Managing Containers with LXD: A Brief Introduction

Today we’d like to continue our blog series on containerization. As our first two articles (1 and 2) were dedicated to theory, this post will focus on one tool and its features: LXD.

LXD (short for Linux Container Daemon) was created by Stéphane Graber, who works for Canonical. His name is well known in the professional community as he is also one of the authors of another popular container solution: LXC. Naturally, LXD is built on LXC, which makes it easier to work with containers and adds a wide range of new abilities.

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Kernel Tracing with Ftrace

There are a number of tools for analyzing events at the kernel level: SystemTap, ktap, Sysdig, LTTNG, etc., and you can find plenty of detailed articles and materials about these on the web.

You’ll find much less information on Linux’s native mechanism for tracing system events and retrieving/analyzing troubleshooting information. That would be ftrace, the first tracing tool added to the kernel, and this is what we’ll be looking at today. Read more

Containerization Mechanisms: Cgroups

Today we’ll be continuing our post series on containerization mechanisms. In our last article on containerization, we talked about isolating processes using the namespaces mechanism. For containerization though, isolating resources isn’t enough. If we launch an application in an isolated environment, we should be sure it has been allocated enough resources and not use an inordinate amount, interrupting the rest of the system. For this task, the Linux kernel has a special mechanism, cgroups (short for control groups), which we will talk about today.

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Data Centers: Standards and Certification

Any individual or company looking to utilize a data center’s services needs a guaranteed level of quality. There has to be some assurance that their equipment will not fail and that their data will always be available (or that in the worst case scenario, their project will quickly be restored).

When it comes to data centers, the most commonly recognized guarantee is certification. Certification asserts that the center complies with a predetermined list of standards. Although issues of standardization have gained particular interest over the past few years, the number of relevant publications on the topic remains low.

In this article, we’ll be looking at the primary regulatory documents for data center certification.

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Containerization Mechanisms: Namespaces

Linux container solutions have gained quite a bit of popularity over the last few years. A lot of people have written or spoken about how containers can be used and what for, but little attention has been paid to the mechanisms behind containerization.

All containerization tools, like Docker, LXC, or systemd-nspawn, are built on two Linux kernel subsystems: namespaces and cgroups. In this article, we’ll be taking an in-depth look at namespaces.

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Systemd and Containers: An Introduction to systemd-nspawn

Containerization has become an increasingly relevant topic. There are already thousands, if not tens of thousands, of articles and posts written about popular solutions like LXC and Docker.
In today’s article, we’d like to discuss systemd-nspawn, a systemd component for creating isolated environments. Systemd is already a standard in the world of Linux and in light of this, it wouldn’t be unfounded to suggest that the potential for systemd-nspawn will significantly expand in the near future. For this reason, we think now would be a good time to better acquaint ourselves with this tool.

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