Developers Club geek daily blog

The thin client of HP as a house router and the file server

1 year, 7 months ago
From the moment of the publication on Geektimes of the first part of article, something changed. I updated the thin client on HP t610 Plus and passed to CentOS 7. Therefore, I publish this article not as continuation previous and as new.

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Quickly lifted it is not considered fallen. We increase fault tolerance of the built-in systems

1 year, 7 months ago
image

A year ago performed quite interesting work on development of the built-in computer for one enterprise which is engaged in electronics. The computer represented nothing essentially interesting: the Cortex A-8 processor working at subgigahertz frequencies, 512Mb as DDR3, 1Gb NAND, lightweight assembly of Linux. However the device which the computer was built in, so and to him should work in quite severe conditions. Broad temperature range (from-40 to +85 Celsius degrees), moisture resistance, resistance to electro-magnetic radiations, kilovoltage impulses on power supply, protection against a statics in 4 kV and a lot of things interesting that is well described in different state standard specifications on special equipment, – all this about it. One of the main requirements of the customer – development term on failure not less than 10 years. At the same time the vendor provides warranty repair of a product within five years therefore a question not rhetorical, but monetary and serious. In a product the corresponding element base was mortgaged. The device with honor passed tests and received required certificates, but conversation not about that. Problems began when the installation lot was produced, and devices dispersed on departments and CB for creation of application software. Returns with the formulation went: "Something is not loaded".

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The VNC installation of the server, and setup of its work over SSH

1 year, 7 months ago

Yes, for some reason not all clients want to work in such convenient and black terminal, the panel completely does not satisfy their esthetic requirements, and in general — "where my such darling and convenient VNC?".
question of a habit and taste

In this article an example of installation and the VNC server setup and a graphic cover (GUI) on the example of OC Debian 8 jessie will be reviewed.

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Adding of packets to the independent Lubuntu Alternate ISO installer

1 year, 7 months ago

Introduction


During creation of independent installation carriers for the automated Lubuntu OS installation 14.04 with use of preseed, I faced that I need to add packets which are absent in an initial alternate-distribution kit on the installation carrier. I tried many different methods of creation of own autonomous distribution kits, but they appeared:


As a result stopped by a method which is described in community Ubuntu.

I want to tell about what at me turned out.

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Multihome IPv4 in Linux

1 year, 7 months ago
Contents: how to make so that the computer answered on the Internet all the IP addresses on all the interfaces, each of which gateway by default. Concerns both servers, and desktops.

Key word: policy routing, source based routing

Lyrics: There are enough articles about policy routing in Linux. But they most often sort the general, thinner and difficult cases. I will sort the trivial scenario of the following type:



To our computer (server) well three interfaces. On each interface the gateway issued it IP (a statics or on dhcp, it is not important) and told "send all traffic to me".

If we leave this configuration as is, then the principle "who will be used the last got up, that and the default gateway". On the picture above if the last the lower interface (241) rises, then all traffic will go to it. If to our server the request for the first interface (188) comes, then the answer to it all the same will go on lower. If the router/provider has at least the minimum protection against counterfeit of addresses, then the answer is just dropnut as non-valid (from the point of view of 241.241.241.1 it sent from a network 241.241.241.0/24 a packet with src 188.188.188.188 that, obviously, should not be).

In other words, in normal option only one interface will work. To make a situation it is worse if addresses are received on dhcp, then updating of lease on other intefreysa can rewrite the gateway by default that means that that interface which worked will cease to work, and other interface will begin to work. Successful stable work to your server, so to speak.

Solution

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"Transparent" Squid with filtering of HTTPS of resources without substitution of certificates (h86, h64 — the universal instruction)

1 year, 7 months ago
Hi everyone! Last article about transparent proxying of HTTPS by means of Squid'a was quite successful. The set of responses about successful installation of this system came by mail. But also also letters with requests for the help arrived. Problems were quite solvable. But not so long ago one colleague about the help in installation of this system on h64 to architecture (Debian) appealed to me. Here we were puzzled. First, it turned out that last article is unsuitable for this purpose because of lack of the necessary source codes in Debian repository (there now 3.5.10). It was not succeeded to find the necessary source codes in the first article Debian'ovskiye, and checkinstall gave strange error messages. Secondly, there was a wish for more universal solution which without problems would work both on h64, and on h86, and (whenever possible) at other distribution kits. The solution was found. Small addition to the previous article + some amendments turned out. This instruction allows to compile both h86, and h64 Squid'a versions and to create the corresponding packets. The instruction will be broken into several points and subparagraphs. If it is interesting, we go under kat:

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collectd + front-end

1 year, 7 months ago


As practice shows — the big part of clients does not monitor the used resources, the services rented by them in any way (especially it is noticeable on the cheap services VPS from $3). That is, after installation of system and setup of software, necessary for the project, the future of the server is assigned to a case. And, when there are problems with operability of the server, information for the analysis has not enough.

Except the set and configured logging in atop (which also meets not often), logs of system, it would be desirable to have more information with which it is possible to work.

In this article procedure of installation and the collectd and collectd-web setup on the example of OS of Debian family will be described.

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And whether it is possible not to pay for a panel? "Coin"

1 year, 7 months ago
There comes the moment when virtual hosting to become insufficiently and your project and "to ask" on the server. Not always for new tasks you need a dedicated server at once, but at least it is worth beginning with the virtual server. At the same time many of you what as to save that begin to look for the partner(s) for lease of more productive service. Also, use of the free software is one of options of economy of the budget —.

Not to each of you, for example, will pleasantly sit in the console and to set necessary for software, or to make management of your websites through a touch the command line. At such moments many webmasters are come to the rescue by control bars a hosting and as it is pleasant when this panel — qualitative and free software. Quite recently we already told about one free software product, and today it will be a question of one more interesting control bar a hosting, namely of "coin" …


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The thin ACPI setup on the example of Thinkpad X220

1 year, 7 months ago

Lyrics


Over last few months I quite often had to get into arguments about various portable computers: the vendor is better to break a spear in what disputes and why, to discuss compatibility with GNU/Linux and how in this system to configure this or that function and, periodically, me ask to share configs. Under the influence of these discussions this article was also born.

The most part of the computer experience I use laptops so-called "business of a series": IBM ThinkPad 600, HP-Compaq nc2400, Lenovo ThinkPad X61T, Lenovo ThinkPad X220.



There were short-term breaks when it was necessary to be interrupted by aby-what, that is computers of a consumer segment: Apple ibook G4 and Acer aspire 5112 and came to these moments understanding of how such obvious and usual things strongly are not enough as trekpoint and a docking station.

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Simple management system computer class

1 year, 7 months ago
Article is written for teachers of information science which bothered to be engaged in permanent recovery of an order in a class and on student's computers. For those to whom time and health is expensive.

It is required to us:

1. To install on all computers of class Linux OS. Distribyyutiv select on the taste.
2. To install packets on all student's computers: openbox, tint2, pcmanfm, gxkb, x11vnc (server and client), vlc
3. Besides on the teacher's computer it is necessary to install the RuleUser program, is more detailed it will be stated below.
4. To create on student's computers of the user of guest.
5. To set and configure sshd packet on all computers.
6. To copy the attached configuration files on student's and teacher's computers.

Note. In this example the computer of the teacher has the IP address: 192.168.1.100/24. Student's computers have addresses, since 192.168.1.101/24.

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