PUBLIC MARKS with tag xen

One of the reasons we use Xen based virtualization is to create a scalable and flexible development and test platform for the Hannibal system stack. Check the Hannibal section of this wiki for more information.

Zentific is a browser-based management interface for clusters of virtual machines running on the open-source Xen® hypervisor. In the spirit of the open-source projects which have made Zentific possible, the application will be released to the community. To ensure that Zentific maintains a high level of reliability, security, and ease of use, we will also be offering a supported version for commercial use.

Out of the box, Zimbra is tuned for a fairly beefy machine. Zimbra will easily consume 1.5GB of ram with default settings. Some of these changes mean turning off a few Zimbra features and there are quite a few ways to do this, so you will need to evaluate memory usage given your own situation. If you simply can't live without *all* the Zimbra features or intend to support a larger (> 15) number of users, my only suggestion is to get more ram ;). But if you are willing to make some compromises, please read on. The changes below are ones that I found to be a reasonable compromise. With a few easy changes, you can bring the memory consumption way down, so that it will hum along just fine on a server with ~512MB of ram. Of course this reduces the amount of users that your server can support, but I've found that for a small installation of around 15 users, these settings will work just fine and give you the same performance as the out-of-the-box config with gobs of RAM. The server I have been testing with has 560MB of ram, and after tuning consumes all the ram and only about 80MB of swap on average. You will find that if you don't make changes similar to the ones suggested below with ~512MB of ram, your Zimbra install will slowly creep up its consumption of swap and your Zimbra install will start to crawl. Also, > 512MB seems to be about the minimum amount of ram to get a useful/zippy server

After my last post on limiting bandwidth usage on a Xen node I thought I would follow up with how to monitor the bandwidth usage of a Xen node. I chose to use netacct-mysql to monitor bandwidth and store the results into a mysql database. This isn't the only way of monitoring the bandwidth but it was easy to set up and stores the information directly into mysql without needing any extra scripts. On the Xen setup I'm using for an example there are 3 nodes and a bucket for each node will be created in the mysql database by netacct. Setting up netacct can be tricky so you will want to check to make sure traffic for each node is going into the correct bucket.

When it's time to convert a physical machine to a virtual one, use these steps to make the move safely and with a small maintenance window.

This document describes how to convert a VMware-formatted virtual machine (VM) into a Citrix XenServer virtual machine.

I have tried to run both Debian Etch and Ubuntu 8.04 Server on the cluster nodes, in Dom0. I started my tests with Debian, but I had some issues with slow samba performance in one VM that I couldn't fix so I decided to try Ubuntu Server, for the first time. Both installation went OK, the main difference was that I used mainly source code in Debian, but only packages in Ubuntu. I actually ran into more problems with Ubuntu due to some early bugs in the 8.04 release, will describe them below as I go along. And I have still to prove that running this setup in Ubuntu is stable.

One of the most compelling features of Xen virtualization is the ability to migrate a domainU guest from one host system to another. Of particular significance, however, is Xen's ability to perform live migrations whereby a running guest domainU system is moved from one system to another such that there is only an imperceptible interruption in service. In this chapter we will discuss the requirements for performing live Xen domainU migrations before walking through an example live migration.

Cet article a pour but de décrire la mise en place de machines virtuelles sous XEN dans un environnement SAN. Il recense les différentes étapes nécessaires et les problèmes rencontrés lors du déploiement de nos machines virtuelles.

In previous chapters we have covered the steps necessary to install and configure Xen and Xen based guest operating systems. This chapter is dedicated to explaining the xm tool, and how it can be used to manage guest operating systems from the command-line. If you prefer to use the graphical virt-manager tool to administer your Xen configuration see Managing and Monitoring Fedora based Xen Guest Systems. Contents * 1 xm Command-line vs xm Shell * 2 Listing Guest System Status * 3 Starting a Xen Guest System * 4 Connecting to a Running Xen Guest System * 5 Shutting Down a Guest System * 6 Pausing and Resuming a Guest System * 7 Suspending and Resuming a Guest OS * 8 Saving and Restoring Xen Guest Systems * 9 Rebooting a Guest System * 10 Configuring the Memory Assigned to a Xen Guest OS * 11 Migrating a Domain to a Different Host

OpenNebula transforms a physical cluster into a flexible virtual infrastructure which dynamically adapts to the changing demands of a service workload. OpenNebula leverages existing virtualization platforms to create a new virtualization layer between the service and the physical infrastructure. This new layer supports the execution of the services on a physical cluster, extending the benefits of VMMs (Virtual Machine Monitors) from a single physical resource to a cluster of resources. OpenNebula effectively decouples a server (deployed as a pre-configured VM) not only from the physical infrastructure but also from its physical location.

L’idée était de profi ter du dimensionnement de ce petit monstre pour monter une plate-forme architecturée autour de Xen. Vous le savez peut-être, chez GCU, on est très BSD. Nous avions donc à l’esprit de monter l’architecture suivante : * dom0 sous NetBSD ; * domU shells, destiné à accueillir des accès ssh pour les membres du groupe ayant cotisé à la mirobolante dîme annuelle ; * domU services, qui hébergera les services classiques hors HTTP ; * domU gcu où se trouvera le site principal et ses moult plugins ; * domU www, domaine où nous hébergerons les sites tiers. Afin de profi ter au maximum de ce nouveau matériel, nous envisagions également, naïfs que nous sommes, de n’avoir que des systèmes de type amd64. Nous verrons que cet espoir s’est envolé. Il est important de noter que si NetBSD dispose d’une version dotée d’un noyau de type domU, ce n’est pas le cas d’OpenBSD, aussi, c’est uniquement grâce au mode HVM (Hardware Virtual Machine) de Xen que nous serons en mesure de mettre en place des domUs ne bénéficiant pas de noyaux modifiés.

By default, migrating a Xen Virtual Machine (VM) resource causes it to shutdown on the current node and restart on the new one. Once you configure a Xen VM within the High Availability Storage Infrastructure (HASI), how do you configure the Xen VM resource to live migrate among the cluster nodes?

The XenAccess project was inspired by ongoing research within the Georgia Tech Information Security Center (GTISC). The purpose of this library is to make it easier for other researchers to experiment with the many uses of memory introspection without needing to focus on the low-level details of introspection. If you are using this library and come up with a useful extension to it, we are always happy to receive patches.