CoreOS Playground With PXE – Introduction [1/5]

CoreOS Playground With PXE

CoreOS is an open-source lightweight operating system based on the Linux kernel and designed for providing infrastructure to clustered deployments and it supports Docker out of the box.

Would not be great to have a CoreOS playground to experiment all mighty stuffs this OS promises? Well, it would, at least for me, and here I’d like to share with you how it is possible to create such environment.

The main objective is to come up with a system running on a single PC that allows a developer to easily run experiments involving CoreOS. Here above there’s a list of things I would like to be able to accomplish with this CoreOS playground.

  • Quickly set up a properly configured CoreOS machine and run Docker containers on it.
  • Quickly bring up additional CoreOS machine to test what happens when a node is added to the cluster.
  • Easily discard an entire cluster to try a new configurations.

To do that, I’m going to set a virtual machine not powered by CoreOS. It will act as a router connecting a NAT network on one side, to provide Internet access, and a CoreOS network on the other.

coreos-playground-network

 

On top of that, this machine will provide DHCP and CoreOS via PXE. This way CoreOS will be installed automatically through PXE. I’ll also set up an empty virtual machine properly configured for lan boot. This way, adding a CoreOS node to the cluster will be just a matter of cloning and starting the template machine. As you probably know, a CoreOS installation can be configured providing a reference to a “cloud-config” file. I’ll set up apache on the router to provide such file to the starting CoreOS nodes through HTTP. The following schema depicts the boot process from a logical point of view.

coreos-playground-pxe

I’m going to use VirtualBox to run the machine and Lubuntu for the Playground Server, even though I’m trying to provide as much command line as I can, so it should be all reasonably adaptable to other environments too.

This is just the first installment of this series. If you are interested, stay tuned for the next posts. I’ll show you how to implement the idea presented here.

Ubuntu Cheat Sheet

Which version is running

Gui

Dash > System Settings > Details > Overview
http://askubuntu.com/questions/12493/how-can-i-find-the-version-of-ubuntu-that-is-installed

Comman Line

Using uname.

$ uname -a
Linux ubuntu-desk-box 3.13.0-35-generic #62-Ubuntu SMP Fri Aug 15 01:58:42 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux

Using lsb_release

$ lsb_release -a
No LSB modules are available.
Distributor ID:    Ubuntu
Description:    Ubuntu 14.04.1 LTS
Release:    14.04
Codename:    trusty

Customisation

GUI

Using about:config

ALT+F2 > about:config

Using gconf-editor

ALT+F2 > gconf-editor

Using tweak tools

sudo apt-get install unity-tweak-tool gnome-tweak-tool

then…

 Dash > unity-tweak-tool
 Dash > gnome-tweak-tool

What to do after clean install

A GUI to manage the firewall

Install a GUI to manage the firewall

sudo apt-get install gufw

A File Manager full of good old fashioned features

$ sudo add-apt-repository ppa:webupd8team/nemo $ sudo apt-get update $ sudo apt-get install nemo nemo-fileroller

sources:

http://askubuntu.com/questions/286056/how-can-i-downgrade-to-an-older-version-of-nautilus

http://www.webupd8.org/2014/04/install-nemo-220-with-unity-patches-in.html

Improve Unity with Drawers

sudo add-apt-repository ppa:ian-berke/ppa-drawers
sudo apt-get update
sudo apt-get install drawers

source: http://www.itworld.com/article/2698427/enterprise-software/install-unity-drawers-in-ubuntu-14-04.html

Useful Commands

Compress a folder

$ tar -zcvf tartest.tar.gz tar

Un’altra edizione di successo del corso Test Driven Development

Studio Danidemi ha appena terminato l’erogazione di un’altra edizione del corso Test Driven Development presso un’azienda operante nel settore Internet e hosting nel torinese. I partecipanti hanno ancora una volta confermato la qualità del corso, confermando la bontà del materiale, della docenza e dei concetti e delle metodologie apprese.

Qui di seguito ecco i risultati del test di valutazione.

Convert of LibreOffice presentations in PDF

Do you need to convert a bulk of LibreOffice presentations in PDF, but you don’t want to do it manually ? Libre Office can be invoked with command line parameters that make it do just that.

For instance the following command…


$ soffice --convert-to pdf *.odp --outdir /tmp/pdfout/

…converts all odp files in the current directory in PDFs stored in the /tmp/pdfout folder.

Studio DaniDemi e Tinvention insieme nella formazione

Studio DaniDemi e Tinvention uniscono le rispettive competenze formative per proporre ai clienti corsi di formazione su tecnologie Java e metodologia TDD basata su stack Java.

Per i nostri clienti c’è quindi la possibilità di usufruire di corsi di formazione che formino sviluppatori che possano velocemente inserirsi in team che adottano metodologie agili.