PUBLIC MARKS with tag xen

The idea of using virtual machines to build high available clusters is not new. Some software companies claim that virtualization is the answer to your HA problems, off course that's not true. Yes, you can reduce downtime by migrating virtual machines to another physical machine for maintenance purposes or when you think hardware is about to fail, but if an application crashes you still need to make sure another application instance takes over the service. And by the time your hardware fails, it's usually already too late to initiate the migration.

In this article, I briefly introduce the concepts of Xen virtualization and Linux clustering. From there, I show you how to set up multiple operating systems on a single computer using Xen and how to configure them for use with clustering. I should point out that a cluster implemented in this manner does not provide the computational power of multiple physical computers. It does, however, offer a way to prototype a cluster as well as provide a cost-effective development environment for cluster-based software. Even if you're not interested in clustering, this article gives you hands-on experience using Xen virtualization.

The "Virtual Machine Manager" application (virt-manager for short package name) is a desktop user interface for managing virtual machines. It presents a summary view of running domains and their live performance & resource utilization statistics. A detailed view presents graphs showing performance & utilization over time. Ultimately it will allow creation of new domains, and configuration & adjustment of a domain's resource allocation & virtual hardware. Finally an embedded VNC client viewer presents a full graphical console to the guest domain.

there are many ways to setup xen, but i've put together a simple step-by-step guide to get a working xen system based on debian etch. easy as pie.

The XenoServer platform is a generic substrate for deploying any kind of competing, untrusted, commercial services (such as gaming-on-demand or p2p streaming applications) at locations of the service provider's choice.

This Article describes Heartbeat2 Xen cluster Using Ubuntu (7.10) OS, drbd8 and OCFS2 (Ver. 1.39) File system. Although here Ubuntu is used it can be done in almost same way with Debian Idea The idea behind the whole set-up is to get a High availability two node Cluster with redundant data. The two identical Servers are installed with Xen hypervisor and almost same configuration as Cluster nodes. The configuration and image files of Xen virtual machines are stored on drbd device for redundancy. Drbd8 and OCFS2 allows simultaneous mounting on both nodes, which is required for live migration of xen virtual machines.

This site provides a variety of downloads and howto’s to facilitate use of the Xen Virtual Machine Monitor. Xen allows you to run multiple operating systems on a single piece of physical hardware. Here you will find Linux distributions that can run as Xen guests out of the box, obviating the need to create your own custom filesystems. The filesystems on this site have already been tweaked to deal with Xen’s idiosyncracies, and are also designed to be lightweight and minimally divergent from the original distribution.

This guide is the first of a series in which I give you detailed step-by-step instructions on how to build a virtual cluster with Xen. The cluster thus built might not be appropriate for your case, and does reflect the author's preferences and/or needs, but if you are new to clusters or Xen, it will hopefully help you get started with both. The goal is to start it simple and then add more complexity as we progress, so in this first guide I show you how to get do the basics: * A Xen installation, the creation of 5 virtual machines (one to act as the master and four slaves), * Shared storage through NFS, * The network configuration on which to build the virtual cluster. The network structure of this first attempt will be very simple, the master having two network cards, one to the outside world and the other one connected through a switch to the slaves.

While consolidating physical to virtual machines using Xen,we want to be able to deploy and manage virtual machines in the same way we manage and deploy physical machines. For operators and support people there should be no difference between virtual and physical installations. Integrating Virtual Machines with the rest of the infrastructure, should have a low impact on the existing infrastructure. Typically, Virtual machine vendors have their own tools to deploy and manage virtual machines. Apart from the vendor lock-in to that specific virtual machine platform , it requires the administrators to learn yet another platform that they need to understand and manage, something we want to prevent. This paper discusses how we integrated SystemImager with Xen, hence creating a totally open source deployment framework for the popular open source Virtual Machine monitor. We will document both development of our tools and go more in depth on other infrastructure related issues when using Xen System Imaging environments in combination with Virtual machines can also be used to ensure safe production deployments. By saving your current production image before updating to your new production image, you have a highly reliable contingency mechanism. If the new production environment is found to be flawed, simply roll-back to the last production image on the virtual machines with a simple update command! Xen has become one of the most popular virtualisation platforms over the last year, although not such a young project, it is now rapidly gaining acceptance in the corporate world as a valuable alternative to VMWare.

Converting a VMWare image to Xen HVM

Xen is great. But installing more than one network card became a pain when I tried it the first time. There are some documents describing the principle but I was unable to find a real life example somewhere else. So this is a summary about how it works here now. Using a bridge for a Dom is generally a good idea but then all packets traversing the bridge can be intercepted by any Dom that is using the same bridge. Having a single network card in a Xen landscape also means that theoretically each Dom would be able to sniff all packets traversing this single network card including packets to and from other Doms. A solution is to have more than one network card attached to Xen using a single network card for a single dom. The scenario described here has a server with 3 network cards installed. The first card should be used to access Dom0 and some other DomNs while the second and third network card should be used to purely access Dom1 rsp. Dom2. The Dom configuration file just needs to select the appropriate bridge for each dom.

The xm command is the main command line interface for managing Xen guest domains. The program can be used to create, pause, and shutdown domains. It can also be used to list current domains, enable or pin VCPUs, and attach or detach virtual block devices.

Nous verrons dans cet article comment installer Xen sur une machine n'ayant pas les instructions matérielles de virtualisation (VT) en utilisant LVM pour partitionner avec flexibilité nos différentes machines virtuelles. Le tout est réalisé grâce à Debian Etch avec les bons noyaux qui vont bien. J'ai aussi utilisé le noyau officiel de chez Xen afin d'avoir quelque chose de propre (enfin dans la limite du possible). Attention, mon tutoriel prends de véritables adresses IP, je n'ai donc aucun besoin de NAT. Si tel est votre problème, achetez le numéro 100 de GLMF, il contient le serveur parfait et un setup bien plus avancé que le miens :)

This short guide describes how to install Windows XP or Windows 2003 Server on Xen. It provides an overview of the Debian Linux Etch installation, and detailed steps for installing and configuring Xen and starting the Windows XP or Windows 2003 Server installation.

We have implemented a 2-node HA Xen cluster, which consists of two physical machines (hosts,) and runs several virtual servers (guests) each, for our company's internal services (mail, web applications, development, etc.) When one host gets down unexpectedly, the other host physically kills it (STONITH - power down or reset) and then takes over all the guests the failed host was running. When we want to shutdown a host machine for maintenance (to replace a fan, add disk or memory, etc.), we just type the usual shutdown command, and the guests are automatically live-migrated to the other host. Since the guest servers keep running throughout the migration process, except for the less than a second pause, users would never even notice the event.

Ganeti is a virtual server management software tool built on top of Xen virtual machine monitor and other Open Source software. However, Ganeti requires pre-installed virtualization software on your servers in order to function. Once installed, the tool will take over the management part of the virtual instances (Xen DomU), e.g. disk creation management, operating system installation for these instances (in co-operation with OS-specific install scripts), and startup, shutdown, failover between physical systems. It has been designed to facilitate cluster management of virtual servers and to provide fast and simple recovery after physical failures using commodity hardware.

Ganeti is a cluster virtualization management system based on Xen. In this tutorial I will explain how to create one virtual Xen machine (called an instance) on a cluster of two physical nodes, and how to manage and failover this instance between the two physical nodes.