Developers Club geek daily blog

We get ramlog on distribution kits with systemd

2 years, 11 months ago
From the "marginal notes" series. It is more not to forget most, but, maybe, to whom and it is useful.

After purchase of Raspberry Pi 2 to replace not lived and weeks of Odroid XU4 slow shamanism on installation and initial setup of system under itself began. What disappointment when favourite ramlog refused not only to be put (hands we will unpack, not lazy) was, but also to be started after forced "implementation". Having despaired and having requested Google, found out that it is not on friendly terms with systemd, from the word "absolutely".

Already practically sobiravshis to fence something special, came across one German post where the "adapted" ramlog was mentioned. The imboweling of immediately downloaded image showed that there just and the fact that I and wanted was made. Therefore, instead of the invention of the bicycle, I suggest to use already ready

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Installation and the Puppet setup of version 3.8 on the example of Centos 6.5

2 years, 11 months ago
Puppet, Chef, Ansible are so-called management systems configurations which can be met often in foreign IT vacancies like Server/DevOps Admin. Actually it is powerful tools which can configure completely the nulyovy server or quickly enough in large quantities recustomize a set of 1-100+ servers. Work with packets, with the command line, files of settings, everything is available.

The high-level overview can be read in a post How to become the puppeteer

Actually to writing of this initial article for Puppet I was moved by extremely scanty description in the results which are found on the Internet. And even when using official documentation you manage to come across a heap grabel and reefs and to receive not that expected.

The reason of use of a branch 3.8, instead of 4.3 consists in use of this version on "my" servers because of existence of these packets in a repo. The paid Enterprise option is also not considered since I did not work with it. The reason of use of Centos – it is rather widespread, including modifed versions from Amazon.

For local tests it is possible to use two virtualka on VirtualBox under CentOS-6.5-x86_64.

For a start two interfaces are configured: for an output in the external Internet and for creation of a local area network for puppet. Hostname will be conditional, and a node for the client (more nodes are possible) Let's register them on all nodes in hosts (of course if only you have under them no DNS of the server).

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Asterisk: Prioritizing of VoIP of a traffic and reservation of Internet access of two providers on MikroTik

2 years, 11 months ago
It would seem the things which are taken out in heading, are rather trivial and described in a set of places of a wide area network, but it only at first sight. Having tested the most often meeting councils I found several "reefs", blocks and even rocky educations.

But all this words, keep to the point.
Rather widespread situation — Asterisk in LKS, behind MikroTik router.
To select a server traffic where PBX is set, the administrator cuts off part of the canal of provider selecting it only for specific IP.
Or other implementation when the necessary traffic is determined not only by the IP address PBX, but also by the size of packets and the protocol.
Tried — works. It is possible to forget? Here not.

What if the administrator wants to merge something from the Internet being in a server konsolka, or on the contrary to send somewhere to the Internet a large number of traffic? Correctly — it is prioritized on MikroTik as well as a useful traffic from PBX that as a result will lead to problems with IP telephony.

The solution is old as IPv4 here — to mark a traffic on the server with Asterisk generated only by it and so that MikroTik could "see", otmatchit it (forgive for so rough anglicism) and to prioritize only it.

The following item we have a reservation of channels from two Internet service providers.
I think that the script from wiki — is familiar to each system administrator using MikroTik routers in the economy
It all is good, but as well as in the previous situation there is a row "but".
To the most powerful of them the name "Connection tracking" also consists it here in what:
when our main ISP desires to have a rest from works just, traffic switches to reserve.

All are seemingly happy, YouTube works, yap too, but how many we would not shout ekspekto potronum
sip reload

and in despair did not try to apply magic of the higher orders
core restart now

SIP registration do not rise.

And the matter is that in the Connection tracking mechanism records from a "old" (main) Internet channel remained to hang and they need to be deleted then registration will successfully rise and calls will begin to pass.

If it is interesting to you how to prove Mikrotik'U who after all a camel, and just as to automate in a script reset of "old" connections, then to you directly under kat.

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Method of fast performance measurement of the accidental server

2 years, 11 months ago
In the world of web development often there is a problem of selection of the server according to a web application, or on - analogies check of performance of the available server. Perhaps, we need to purchase the new server that it maintained estimated loading. Perhaps, the customer gives us for deploya the available server. Anyway, if after expansion and an application launch it shows poor performance, then will ask from command.

The main problem is that it is necessary to expedite a server performance assessment, without use special (read, difficult) tools and, certainly, to release. We have to be able to remove certain metrics from the server and, having increased them by the known indicators of the application, to receive application performance assessment on this server.

In life not each developer can carry out this task, and from remained not everyone wants to execute it.

In this article I want to tell about those acceptances and tools which we use for a server performance assessment.

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Installation and LXC setup for Debian 8

2 years, 11 months ago
On the previous Debian versions I successfully used technology of virtualization OpenVZ. She completely suited me, despite existence of some disputed issues. Installation of this technology did not go on Debian 8 Jessie in any sauce. Later my guesses about impossibility of existence of OpenVZ on Debian 8 are also more senior were confirmed on In the same place the alternative — LXC was offered that I also decided to try.

Briefly I will describe a method of installation and the LXC setup for Debian Jessie.

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Something "steals" the place on a disk?

2 years, 12 months ago
If you do not monitor the remained empty seat in the root section — you unpleasant news can expect that. In case of overflow of this section, services, important for your project, will cease to work. Agree, idle MySQL or web server will affect the project not in the best way.

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Questions for new interview with Eduard Shishkin

3 years ago
Agreed with Eduard Shishkin, the FS Reiser4 developer, about new interview (interview of five-year prescription can be read according to the link).

In comments it is possible to leave the questions. Interview will be published by me here, on Habré.

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Samba and illegal characters

3 years ago
Samba (samba) under Linux. This surprising software presented to linuksoida a possibility of communication with the world of Windows.
I remember that marvelous feeling when in the local area network the first appeared my a samba server. Eh, there was time!

But a post not about it. Not on a naslyshka I know that many are irritated by limited support of special characters in Windows. But it is not an occasion to refuse them, isn't it?


Details of my misadventures and (almost) happy final under a cat. Let's start!

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Who was on the server?

3 years ago
There comes the moment when the system administrator needs to define date of the last login of each of users, and also to prepare the list of those accounts which did not make it. If you do not know the lastlog command earlier, then would be surprised, how easily and quickly it can provide you these data.

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The IPv6 setup in Linux Debian v7.XX, Ubuntu v14.XX, CentOS v6.XX and FreeBSD v10.XX OS

3 years ago
The material stated below does not apply for an exclusivity. However I had to bring together him on particles from different sources, checking something experimentally. After that the idea to systematize the gained knowledge and experience was born, having stated everything in one note.

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