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OpenVZ Mount Tutorial: Mount Host Devices, Partitions, Directories in Containers (Debian, Ubuntu)

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Sometimes you are in a situation where you need to mount a hard drive, partiiton or directory from the OpenVZ host inside an OpenVZ container - for example, you add a fast SSD to the host and want to put your container's MySQL databases on it to make MySQL faster. This tutorial explains how you can mount host devices/partitions/directories in an OpenVZ container with bind mounts. read more...
permapage | score:9726 | -falko, July 22, 2012

VPS: Xen vs. OpenVZ

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This is a short overview of the key differences between OpenVZ and Xen that you might consider when choosing a VPS. Note that this article is based on my opinions and that you must do your own research to determine which, if either, technology is best for you and your application.

First, some terminology. OpenVZ isn't fully virtualized and could be more properly referred to as a 'container', not a VPS. That shouldn't affect your choice. It's the technical differences that matter.

Cheap VPS offers are everywhere lately, it seems. However, upon closer inspection I saw that almost all of the low-priced offers were for OpenVZ. While both Xen and OpenVZ offer their advantages, I chose Xen. So, there's my first bias, right up front. :)

OpenVZ advantages:

  • Efficient (fast)
OpenVZ disadvantages:
  • Shared kernel (no custom kernel)
  • Shared memory with other users
  • Vendor can easily oversell, killing performance
Xen advantages:
  • Dedicated memory
  • fully virtualized (can run other kernels or even OS's)
  • vendor more limited in overselling
Xen disadvantages
  • Less efficient (more overhead due to a kernel-per-VPS)

You'll notice I left price out of the above comparison. In theory, there should be a small price advantage for OpenVZ. I don't know how big it should be but it pertains to two things: 1) Xen uses more memory due to each VPS having its own kernel, and 2) Xen uses more CPU, also due to the additional software layer required to virtualize the kernel.

In practice, however, the price gap appears larger than the above technical differences suggest it should be. I think the remainder of OpenVZ's price advantage is based on 1) the ability for a vendor to easily oversell OpenVZ, and 2) The price competition that results from some vendors overselling OpenVZ.

OpenVZ doesn't encapsulate its containers into a fixed amount of memory, so it runs processes in the host environment to monitor memory usage and kill processes as a container allocates more than its assigned amount.

As a result of this difference, loading down an OpenVZ container is problematic. To partially offset this disadvantage, most OpenVZ vendors offer 'burst' memory in addition to 'dedicated' memory. That is, the monitor process is set to allow the container to use more than its allocated memory -- for a short period of time. This messy situation results in a potentially unreliable environment as some of your processes may be arbitrarily killed -- at the busiest times.

Xen, on the other hand, allows the use of a swap space and excess memory allocation results in (hopefully) idle segments being rolled out to the swap area. While this is good for the memory-hungry VPS user, it can consume significant I/O capacity when memory is overallocated to the point of busy segments getting swapped out. This is bad for everyone sharing the underlying hardware.

I see Xen as clearly the superior technology. A Xen VPS feels and behaves more like a dedicated server. However, I still would have purchased OpenVZ at some price difference. After a bit of research, however, I located Xen VPS's at practically the same price as the cheapest OpenVZ containers. That made my decision easy.

With that said, keep in mind that a bad hosting vendor can ruin either technology through various means. Both technologies share the disk drives and I/O paths as well as the processor cores. Hardware can be poorly configured and managed in any case. A reputable vendor is probably the single most important consideration in choosing a virtual server.

Lastly, carefully check the 'allowed use' policy. Make sure your application is allowed on the server you intend to purchase. Note that due to their different characteristics, the allowed use policy may differ between OpenVZ and Xen for the same host. Also, it's good to understand the memory usage characteristics of your applications. If you know how much memory/swap they require on a physical system, it'll probably work with that same amount of memory/swap on Xen.

[I'll post a review shortly of my current VPS vendor and I will then add a link to that article here.]

mail this link | permapage | score:9516 | -Ray, June 13, 2011

Using OpenVZ on Debian 7 (AMD64)

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In this HowTo I will describe how to prepare a Debian Wheezy server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:9399 | -falko, June 7, 2013

Installing OpenVZ on CentOS 5.7

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In this HowTo I will describe how to prepare a CentOS 5.7 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:9036 | -falko, November 7, 2011

Installing OpenVZ on CentOS 6.3

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In this HowTo I will describe how to prepare a CentOS 6.3 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8832 | -falko, August 6, 2012

Install and use OpenVZ on Ubuntu 13.04

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In this HowTo I will describe how to prepare an Ubuntu 13.04 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8776 | -falko, July 19, 2013

Convert Debian systems and Xen VMs into OpenVZ containers

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This guide explains how you can convert physical systems (running Debian Etch) or Xen domUs (also running Debian Etch) into an OpenVZ container. This procedure should also work for converting VMware VMs, VirtualBox VMs, or KVM VMs into OpenVZ containers, but I haven't tried this. It should work for other Linux distributions as well, with minor modifications (for example, the network configuration is not located in /etc/network/interfaces if you're not on Debian/Ubuntu). read more...
permapage | score:8738 | -falko, January 16, 2009

Using OpenVZ on Scientific Linux 6.3

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In this HowTo I will describe how to prepare a Scientific Linux 6.3 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8548 | -falko, February 18, 2013

Create a Debian Wheezy OpenVZ template

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This tutorial explains how to create an OpenVZ template for Debian Wheezy (Debian Testing) that you can use to create virtual Debian Wheezy machines under OpenVZ. I searched for a Debian Wheezy OpenVZ template, but couldn't find one, that's why I decided to create it myself. This guide can also be used for creating Debian Lenny templates and templates for recent Ubuntu versions. read more...
permapage | score:8547 | -falko, September 15, 2011

Install OpenVZ on CentOS 5.6

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In this HowTo I will describe how to prepare a CentOS 5.6 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8472 | -falko, April 28, 2011

How to Install and Use OpenVZ on Ubuntu 10.04

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In this HowTo I will describe how to prepare an Ubuntu 10.04 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8393 | -falko, August 24, 2010

OpenVZ Tutorial: Build virtual host with Web, MySQL, Email, DNS servers on Debian 6

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This tutorial describes how you can set up a single dedicated server as a virtual multiserver environment using OpenVZ with dedicated Web & MySQL, Email and DNS servers on Debian Squeeze. Also, you will learn how to maintain all these servers. As an addition, you will learn how to install some very useful packages on all of them, how to protect them and how to monitor them. At the end you will have a fully functional virtual multiserver environment, ready for shared hosting. read more...
permapage | score:8364 | -falko, May 26, 2012

Installing, Using OpenVZ on CentOS 6.4

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In this HowTo I will describe how to prepare a CentOS 6.4 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8323 | -falko, April 7, 2013

Install OpenVZ on Debian 6

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In this HowTo I will describe how to prepare a Debian Squeeze server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:8200 | -falko, February 17, 2011

Tutorial: Install OpenVZ plus VM Management on Debian 6.0

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This tutorial describes the installation of an OpenVZ host server to manage virtual machines from within the ISPConfig 3 hosting control panel. OpenVZ is a lightweight virtualization technology for Linux servers, similar to jails on *BSD systems. ISPConfig 3 contains a module to manage OpenVZ virtual machines on the local server and on remote servers that run ISPConfig. read more...
permapage | score:8126 | -falko, January 12, 2012

Tutorial: Install WebVZ on Debian to manage OpenVZ

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WebVZ is one of the simplest and most powerful web management tools for OpenVZ. This tutorial shows how to install it on a Debian Etch system.
First you must have OpenVZ installed and configured. You can find a tutorial to do this on HowtoForge. Because of a small problem/error in Debian Etch, it is not possible to update the Rubygems system because a Require in the gems is missing. But we can solve it with a simple edit of the file.
read more...
permapage | score:8024 | -falko, May 30, 2008

Install OpenVZ on Fedora 14

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In this HowTo I will describe how to prepare a Fedora 14 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:7925 | -falko, December 17, 2010

Install OpenVZ on CentOS 6.0

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In this HowTo I will describe how to prepare a CentOS 6.0 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:7873 | -falko, August 1, 2011

Tutorial: OpenVZ on Fedora 15

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In this HowTo I will describe how to prepare a Fedora 15 server for OpenVZ. With OpenVZ you can create multiple Virtual Private Servers (VPS) on the same hardware, similar to Xen and the Linux Vserver project. OpenVZ is the open-source branch of Virtuozzo, a commercial virtualization solution used by many providers that offer virtual servers. The OpenVZ kernel patch is licensed under the GPL license, and the user-level tools are under the QPL license. read more...
permapage | score:7767 | -falko, July 5, 2011

Tutorial: Install OpenVZ under RHEL / CentOS Linux

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OpenVZ virtualization uses the concept of containers to run Linux only instances on the same hadware. OpenVZ is an operating system-level virtualization technology based. It allows a physical server to run multiple isolated different Linux distributions operating system instances, known as containers or Virtual Private Servers (VPSs), or Virtual Environments (VEs). It's similar to FreeBSD Jails and Solaris Zones. This article explains how to install and setup VEs under RHEL and CentOS Linux server 5.x. read more...
mail this link | permapage | score:7727 | -nixcraft, August 8, 2009
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Articles are owned by their authors.   © 2000-2012 Ray Yeargin