Peter Havrila

Author Archives: Peter Havrila

Tutorial for creating first external SDN application for HP SDN VAN controller – Part 2/3: Influencing Flows via cURL commands

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In this tutorial series, I will show you by example, how to build your first external REST API based SDN application for HP SDN VAN controller, with web interface for the user control. Target will be to learn how to use REST API, curl and perl scripting to generate some basic and useful code to view and also manipulate network traffic.

This article is part of “Tutorial for creating first external SDN application for HP SDN VAN controller” series consisting these articles:

In this Part 2/3, we will discuss how to create a few cURL commands in linux environment, authenticate to the controller REST API interface and generate flows to modify the forwarding path overriding the controller decisions.

Step 1) cURL command line tool to authenticate to the REST API and receive a token

Lets start with the basics, in linux console exists Continue reading

Tutorial for creating first external SDN application for HP SDN VAN controller – Part 1/3: LAB creation and REST API introduction

For best article visual quality, open Tutorial for creating first external SDN application for HP SDN VAN controller – Part 1/3: LAB creation and REST API introduction directly at NetworkGeekStuff.

In this tutorial series, I will show you by example, how to build your first external REST API based SDN application for HP SDN VAN controller, with web interface for the user control. Target will be to learn how to use REST API, curl and perl scripting to generate some basic and useful code to view and also manipulate network traffic.

This article is part of “Tutorial for creating first external SDN application for HP SDN VAN controller” series consisting these articles:

In this Part 1/3, we will discuss creation of a quick development lab with HP SDN VAN controller and Mininet network and explore the REST API interface quickly.

Internal vs External SDN applications

The difference is this, external applications do not need to run inside the SDN controller itself and can rely on REST API commands transferred over network from Continue reading

Tutorial: Email server for a small company – including IMAP for mobiles, SPF and DKIM

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email_iconA few months back my wife started a small business. Of course I was the one to build the “IT stuff” here that included a website, some reservation system on it for customers (php programming here), local network in the office and customer area and other things. Most of that was all pretty common tasks for me with the exception of one, building an email system for a company emails. So I built it and since it was new and interesting experience for me, I will share here a quick tutorial (or better call this a cookbook?) to replicate the very minimum system.

Now also let me state here that I really missed somehow in my life running a real email system so far. And it was a little challenge to setup it properly for the first time. I always thought in the past that installing SMTP daemon in linux and activating it for all local users was all that I will ever need (because up to this point my needs were only to receive Continue reading

Eycalyptus – cloud introduction and auto-scaling tutorial

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In this article, I will show how to do a very simple auto-scaling system on eucalyptus cloud using the wonderful eucalyptus fast start image. Afterwards you will appreciate how easy and configurable the Eucalyptus cloud is in regards to configuring customization scripts on systems that are booted dynamically inside auto-scaling triggers (like low CPU, RAM, etc… ).

A little history, last year (2014), HP has requisitioned a company called Eucalyptus, what I must admit surprised me after spending so much time with OpenStack. So I tried to get an idea why this move has happened and what are the main differences that immediately come to mind to compare these two.

So let me went with you on the first example exposure to Eucalyptus.

eucalyptus-logo… demo experience

Prerequisites:

  1. Physical system with Intel-V or AMD-x virtualization on CPU
  2. Virtual server running in hypervisor that supports nested virtualization (KVM or vmWare)

The target requirements

1)      Have a cloud system with capability to deploy a server quickly
2)      Test basic systems like load-balancing
3)      Check the network forwarding inside the cloud
4)      Demonstrate auto-scaling system of Eucalyptus on Continue reading

Introduction and LAB tutorial of HP Helion Community Edition, the OpenStack based “cloud” system that can give you a personal cloud!

For best article visual quality, open Introduction and LAB tutorial of HP Helion Community Edition, the OpenStack based “cloud” system that can give you a personal cloud! directly at NetworkGeekStuff.

Hewlett-Packard (HP) is a long enterprise  supporter of cloud technologies and early this year, they released publicly HP Helion Community Edition (CE). HP Helion is HP’s OpenStack based cloud system with which HP plans to provide value added services (both in sense of software and service) with the upcoming release of HP Helion Enterprise edition later this year. In this article, I plan to introduce you to the HP Helion CE, quickly guide you through the installation, basic operations and in the end get you a quick view on the OpenStack architecture in general.

HP and “clouds”

HPCloud

For a long time HP has been providing cloud solution based on their internal Cloud Service Automation or “CSA” system to enterprise grade customers as part of their portfolio. I had access to several projects using this environment and although I still have mixed feelings about their effectiveness, they were a step in the right direction as classical (now called “legacy”) data-centers are loosing popularity to cloud and other automated systems.  The Continue reading

[minipost] Mikrotik/RouterBoard port-knocking example for firewall/NAT openings

For best article visual quality, open [minipost] Mikrotik/RouterBoard port-knocking example for firewall/NAT openings directly at NetworkGeekStuff.

The situation is very simple, you are away from home (imagine visiting a friend or being at work), but you desperately would like to access your internal LAN FTP/Samba/etc… , but you do not have with you your own notebook or any device with a VPN capability to tunnel to your home securely. So what to do ? You do not really want to open your home firewall and NAT whole internet to the internal PC or server on your LAN. Lucky for you, there exists a trick under a name of “port-knocking” where you can send to your home firewall a sequence of TCP or UDP packets with specific ports (the ports act as a password) and your home system can temporarily open the firewall and NAT to only your source IP from which these packets arrived. In this quick example I will show you how to do this on Mikrotik (where I do this for several years now) and I will point you to generic linux tutorial for the same using iptables in links below.

Main Example

Target: I want to access my Continue reading

[minipost] How to fix MySQL lost table description from .frm files after emergency migration of /var/lib/mysql

For best article visual quality, open [minipost] How to fix MySQL lost table description from .frm files after emergency migration of /var/lib/mysql directly at NetworkGeekStuff.

TuxTIP_mergedIn May 2014, networkgeekstuff.com got a small problem when the hosting BeagleBone Black went dead and the old Raspberry PI environment was on that point already used for another project. I was forced to migrate quickly to a virtual server hosting company that I use. Actually it was a performance boost and quick quick, my MySQL and Apache migration scripts for backup recovery made the transition in ~2 hours. But last week I noticed that my MySQL backup system had troubles with two WordPress tables.

 

The MySQLdump was telling me that two tables do not exist with this message:

[email protected]:~/scripts/tachicoma_remote_backup# mysqldump -h localhost -u mysqlbackuper -p<removed> wordpressikdata > wordpressikdata.sql
mysqldump: Got error: 1146: Table ‘wordpressikdata.wp_rfr2b_options‘ doesn’t exist when using LOCK TABLES

[email protected]:~/scripts/tachicoma_remote_backup# mysqldump -h localhost -u mysqlbackuper -p<removed> wordpressikdata > wordpressikdata.sql
mysqldump: Got error: 1146: Table ‘wordpressikdata.wp_rfr2b_options‘ doesn’t exist when using LOCK TABLES

But when I looked at /var/lib/mysql/wordpressikdata, the files for these tables are there, and show tables showed these tables as well.

mysql> show  Continue reading

Slovak Air Force MiG-29 with 2008 Digital Camoflage, 1/48

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I am failing to find words to describe this very beautiful 1/48 scale model, but this one is simply very special for me. First reason is that as a Slovak national, it was very enjoyable to be able to build this majestic plane. Second reason is that I was able to finally incorporate proper pre-shading technique along with manually painted (with painfully detailed masking) of the digital camouflage pattern this plane uses. The painting of this one actually took me two weeks of work every evening (yes, I have full time job, so that is the best I can have). Because this plane is so special for me , I will also make this article a little bit different as well. So this time it will not be only a simple few picture gallery, but I will actually go a little bit over the construction right after that.

MiG-29AS in Slovak Air Force
(super quick history)

Slovak Air Force MiG29 - plane number #0921

Slovak Air Force MiG29 – plane number #0921

The Mikoyan MiG-29 (Russian: Микоян МиГ-29; NATO reporting name: “Fulcrum“) is a fourth-generation jet fighter Continue reading

Playing with the new HP SDN Controller – including getting started guide with Open vSwitch in GNS3

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So, HP has made one if its significant moves last November (2013) with the first public release of their OpenFlow based SDN VAN Controller 2.0. And because you can download it for free in 60 day trial as an ubuntu package, I wanted to create a nice environment for myself where I can play with it and some OpenFlow enabled switches effectively. This I achieved using the good old GNS3 simulator and importing VirtualBox linux hosts there, one for the SDN controller running on ubuntu system, and several small debian systems running Open vSwitch that will act as OpenFlow SDN switches.

Target solution of this GUIDE:

So lets make this article organized, first what is our target. We want to have two VirtualBox systems ready:

  1. Ubuntu with HP SDN Controller 2.0 installed
  2. Open vSwitch in OpenFlow mode running on debian (controlled by the HP SDN controller)

And we want it all inside GNS3 to be able to play in virtual environment anytime. The two cisco router are actually only simulating end PCs Continue reading

Nexus 7k – Getting Started Examples – Part1 (basics, VDC and vPC)

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So I finally had a project with Cisco Nexus switches to finally get hands on experience on these boxes. I am no longer a fanboy of Cisco, so just practically, this article is a summary of my notes and example configurations that I have put together as a documentation for myself and now I will kind of share them with you. First of all, when I started writing this article it was November 2013 and Nexus 9000 were just released, note that this articles is based on Nexus 7000 series and not the new 9000 series. Sorry, not chance to get to 9000 yet, maybe later.

Cisco Nexu Thumbnail FINAL

Let’s get started. Similarly as with my previous IOS XR Getting Started Guide (part 1 and part 2), I will go over the very quick overview and then show basically a snapshots of configuring some elemental configurations. There is actually one advantage over the IOS XR in that the NX-IOS has and that is that it is more similar to the classical IOS we all know.

Basic commands to verify hardware, Continue reading

[minipost] Create a loopback hard-drive partition inside a file in linux

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TuxTIP_mergedThis article is really just a quick documentation for something that I do almost each year, and each year I must google-search how I did the last time. So from now on I will have it in my own notes …. here!

Mu current problem was that I have VPS system from a small provider hpcloud.com :) , but the base image is divided to 10 GB of system partition and another 20 GB of data partition. And as luck would have it, I needed 25 GB for data. One of the options was to buy more storage, but I have seen that my minimalistic debian hardly used more than 1,7 GB from the 10 GB system space and I wanted to make use of the remaining space.

Additionally, resizing the partition was not an option as this was the provider mandatory separation, so I decided to use a loopback file emulating a hard-drive.

What this means is that I will create a 5 GB file in the system partition, and mount it as a directory in the data partition, Continue reading

ArmA2 CWR2 mod: Winter Kolgujev + Malden Domination with Xmas extras

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Last year, I released quickly one nice modification to my custom Malden CWR2 Domination and despite being only announced really only on this blog and to few of my friends last year, I really enjoyed creating it. So this year I decided to put off some dust from it and also port it to a fully winter themed island of Winter Kolgujev from the latest CWR2 mod. Again, this is based on Xeno’s Domination and original port to Everon by OC, then customized on a scripting level with multiple features.

ThumbnailWinter

Features:

Christmas/Winter centric features:

  • Permanent SNOW FALL + FOG during the mission to have a deep atmosphere + in Malden also custom environment sounds, that is why the file is a bit bigger.
  • All CWR2 infantry units are using Winter camouflage (see pictures below, great work from CWR2 mod team to release this)
  • There are Christmas presents under a tree for your team, but be careful, if you fail to protect some girls in the base, you will loose the presents.
  • Custom Christmas carol music in intro + if you Continue reading

BeagleBone Black replaced Raspberry PI running networkgeekstuff.com (and performance reasons review)

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With Raspberry PI, a very great microPC platform that started a trend of its own with two million RasberyPIs sold, a new market has emerged calling for microPC segment companies to compete. One of such alternative companies is BeagleBone and their very nice product is BeagleBone Black. So in this article, I would like to present the BeagleBone Black with some quick view on its abilities and because one BeagleBone Black has arrived to me a while ago, I can compare it with my older Raspberries. And most importantly, why the performance was so good that this web has moved to BeagleBone Black and abandoned Raspberries (while old Raspberries are now only as cold backup).

BeagleBone Black now runs networkgeekstuff.com

BeagleBone Black now runs networkgeekstuff.com

If you remember from my previous blogposts, RasberryPI is a platform on which actually this webserver is running during writing of this article (and you can read about building web server load-balanced on two RasberryPIs on in my previous tutorial articles). So I really found myself a useful work for my RaspberryPIs and I am from that point very Continue reading

Revell F-104G Starfighter 1/48

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Ok, this time there is something special, this is my first model where I used an air brush. As a complete beginner I got the Revell AirBrush starter kit as visible below. I was very happy with it, despite the fact that you cannot do much details with the basic pistol that is creating a paint flow that is too wide.

Revell basic AirBrush set

Revell basic AirBrush set

Regarding the F-104, let me borrow from wiki :
[wikipedia.org]:

The Lockheed F-104 Starfighter is a single-engine, high-performance, supersonic interceptor aircraft originally developed for the United States Air Force (USAF) by Lockheed. One of the Century Series of aircraft, it was operated by the air forces of more than a dozen nations from 1958 to 2004.

The F-104 served with the USAF from 1958 until 1969, and continued with Air National Guard units until 1975. The National Aeronautics and Space Administration (NASA) flew a small mixed fleet of F-104 types in supersonic flight tests and spaceflight programs until 1994.[2] USAF F-104Cs saw service during the Vietnam War, and F-104A aircraft were deployed by Pakistan briefly during the Indo-Pakistani wars. Continue reading