Scott Dowdle's blog

Installing and using OpenVZ on CentOS 5

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I wrote up a HOWTO for the CentOS wiki entitled, Installing and using OpenVZ on CentOS 5, and thought I would share it here as well.

Please note that the OpenVZ kernel is a product of the OpenVZ Project 
and is NOT supported by CentOS. The OpenVZ Project follows the RHEL 
kernels closely and provides updates in a somewhat timely fashion 
after updated Red Hat (and CentOS) kernels are released. As a result 
the RHEL-based OpenVZ kernels are well suited for use on RHEL and 
CentOS hosts with support for (almost) all of the same hardware. 
Please note though that the OpenVZ kernel is less modular than the 
stock Red Hat / CentOS kernels with some hardware support being 
compiled in. 

It is recommended you read this HOWTO in its entirety before 
attempting any of the operations shown in it.

What is OpenVZ?

OpenVZ is operating system-level virtualization based on a modified Linux kernel that allows a physical server to run multiple isolated instances known as containers, virtual private servers (VPS), or virtual environments (VE). The preferred term these days is container. Containers are sometimes compared to chroot or jail type environments but containers are really much better in terms of isolation, security, functionality, and resource management.

OpenVZ consists of a custom Linux kernel (available from the OpenVZ Project) and some user-level tools. OpenVZ is very portable, does not rely on VT support in the CPU, and as a result it is available for a number of CPU families including x86, x86-64, IA-64, PowerPC and SPARC.

OS-level virtualization is quite different from machine / hardware virtualization products such as VMware Server, Parallels Workstation, VirtualBox, QEMU, KVM, and Xen in that with OpenVZ you can only do Linux on Linux virtualization.

OpenVZ modifies the Linux kernel to add advanced containerization features which allow for isolated groups of processes under a parent init along with about twenty dynamic resource management parameters for controlling container resource usage. The OpenVZ Project maintains three stable kernel branches:

  1. RHEL4 / CentOS4 2.6.9 based
  2. RHEL5 / CentOS 5 2.6.18 based
  3. Vanilla 2.6.18 based

There are a number of unstable branches based on newer versions of the Linux kernel that may eventually reach stable status.

Server Outage?

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I was in the middle of doing an rsync backup of the server when I lost communications with it. I did a few traceroutes and filed a trouble ticket with the colocation service. Follow along to see what happened.


Report: Linuxfest Northwest 2008

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Entry BannerDan, Warren and I returned Monday afternoon from the Linuxfest Northwest 2008 event. What follows is my review of the show.


Introduction

For those unfamiliar with the Linuxfest Northwest, it is an annual, two-day event held at Bellingham Technical College in Bellingham, Washington on the last weekend in April. It has become a hub of Linux activity in the Northwest with several of the Washington area Linux Users Groups supporting it. Visitors seem to come from all over the country especially those places that don't have a Linux conference anywhere near them. I also attended the LFNW last year so a bit of this review compares this year with last.

Let's get this out of the way... it was obvious that there were less visitors to the show this year than last year. I haven't seen any numbers published yet though. While that might sound bad it did make for a better show as it allowed for more time with the presenters and the exhibit booth folks.

OS Virtualization vs. Hardware Virtualization

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Presentation PDFSlides PDFI'm all done with making the slides for my presentation on OS Virtualization vs. Hardware Virtualization for the Linuxfest Northwest 2008 conference.

Check out photos in the photo gallery. Thanks goes to Warren for letting me borrow his camera. All photos are licensed under a Creative Commons license so do with them what you will.

Update: Ok, here's the video of my presentation.

Creating an OpenVZ OS Template for Fedora 9 Preview

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I decide to create an OpenVZ OS Template for Fedora 9 Preview. I hope to use it at the Linuxfest Northwest 2008. Creating an OS Template wasn't too hard. Actually, I created two OS Templates. One was a "minimal" and the other was a "withGUI". The "withGUI" includes KDE, GNOME, XFCE, all of the desktop apps like OpenOffice.org, GIMP, Inkscape, etc. Creating an OS Template that includes one or more desktop environments can be tricky. Admittedly, not very many people would want to use the Fedora 9 Preview after the official release comes out but these instructions should also apply to the final release if you replace the Preview DVD .iso image with the final release .iso. Read the full article for all of the details.


Review: Fedora 9 Preview

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Boot SplashBoot SplashYesterday the Fedora Project released a "Preview" of Fedora 9. Today Ubuntu released a "Release Candidate" for 8.04 "Hardy Heron" and the openSUSE team released openSUSE 11.0 Beta 1. Since my preferred Linux distribution for the desktop is Fedora, I've been keeping up with all of the test releases. What follows is some commentary about my experiences with the Fedora 9 Preview including an image gallery. I'd like to encourage MontanaLinux users of other distros to write up their experiences with their preferred distributions.

Triumph of the Nerds

If you haven't seen the Triumph of the Nerds series from PBS' Robert X. Cringely, check it out! It was made in 1996... but it is still fascinating for anyone who either lived through it or is interested in computer history.


Part 1

Part 2 and 3 are in the full article.

Linuxfest Northwest 2008 Prelude

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The Linuxfest Northwest 2008 show is quickly approaching - April 26 & 27 in Bellingham, Washington. It happens to be the closest Linux show to Montana that I'm aware of. Last year Warren, Donnie, Ken and I went. It was a blast. Check out my report from last year if you missed it.

Anyhoo... several of us are going and I've even signed up for a presentation entitled OS Virtualization vs. Hardware Virtualization. I haven't put together the presentation yet but I have done about a half dozen related presentations over the last two years. I think with this one though, I'm going to concentrate less on specific products and more on how OS Virtualization has been making its way into the mainline Linux kernel (called CGroups or control groups).

If anyone is interested in attending the conference, please let me know ASAP. We currently have one vehicle going and one room... but we could easily expand that if need be.

Warren and I have attended three different Linux conferences in the past: Linux World Conference and Expo (once last year), Colorado Linux User Expo (twice back in the 90s - now defunct), and the Linuxfest Northwest (last year). Of the three LFNW, is the only completely free one and as such it has the strongest community feel to it. The schedule has been finalized... so check it out to see just how many things interest you... and don't forget about the exhibits either. There is a LOT there!


BozemanLUG March Meeting Canceled

My wife is sick and will probably be hospitalized for a few days... so I won't be able to make the meeting tonight... so it has to be canceled. Sorry about the last minute notice but it is the best I could do. See you next month.


The Importance of FOSS and Open Standards

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What to know why FOSS (Free and Open Source Software) and open standards are important? South African Minister of Public Service and Administration Geraldine Fraser-Moleketi does a wonderful job explaining in her opening remarks for the Idlelo African Conference on FOSS and Digital Commons. A text version of her speech is also available.

Let's hope that more politicians and decision makers around the globe become as informed as those in South Africa.

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