PUBLIC MARKS with tags server & xen

If you're using LVM based storage for your domains this script will create a snapshot and backup each server to a local drive or a remote system using rdiff-backup.

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

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.

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.

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.

This tutorial provides step-by-step instructions on how to install Xen on an Ubuntu Hardy Heron (Ubuntu 8.04) server system (i386). You can find all the software used here in the Ubuntu repositories, so no external files (apart from a fixed Ubuntu Xen kernel to enable networking for the virtual machines) or compilation are needed.

OpenNEbula (former GridHypervisor) is a virtual infrastructure engine that enables the dynamic deployment and re-allocation of virtual machines on a pool of physical resources. ONE (OpenNEbula) extends the benefits of virtualization platforms from a single physical resource to a pool of resources, decoupling the server not only from the physical infrastructure but also from the physical location.

Openfiler is a powerful, intuitive browser-based network storage software distribution. Openfiler ScreenshotsOpenfiler delivers file-based Network Attached Storage and block-based Storage Area Networking in a single framework. Openfiler is built on the rPath Linux metadistribution and is distributed as a stand-alone Linux distribution. The entire software stack interfaces with third-party software that is all open source. File-based networking protocols supported by Openfiler include: NFS, SMB/CIFS, HTTP/WebDAV and FTP. Network directories supported by Openfiler include NIS, LDAP (with support for SMB/CIFS encrypted passwords), Active Directory (in native and mixed modes) and Hesiod. Authentication protocols include Kerberos 5. Openfiler includes support for volume-based partitioning, iSCSI (target and initiator), scheduled snapshots, resource quota, and a single unified interface for share management which makes allocating shares for various network file-system protocols a breeze.

One advantage of server virtualization is the ability to rapidly provision new production environments. Automatic virtual machine deployment can significantly speed up the time to instantiate new services or reallocate resources depending on the user needs. This article focuses on the integration of SystemImager and Xen to create a totally open source framework able to manage on-demand deployment of virtual machines, such as physical machines, using a single centralized point of management. This approach allows to strongly reduce IT costs and simplify administrative tasks for enterprise data centers, even with a complex and/or reduced set of hardware resources, exploiting the dynamic-provisioning functionalities of SystemImager and virtualization advantages of Xen.

Enomalism Beta Program ¶ The Enomalism cloud computing platform currently in beta and is available to select Enomaly partners. Please enter tickets using the New Ticket link above. Full source code is available under Browse Source. What is Enomalism? ¶ Enomalism is an open source web-based virtual infrastructure platform. Designed to answer the complexity of managing globally disperse virtual server environments. Enomalism helps to automate the transition to a cloud computing environment by reducing an IT organizations overall workload. The easy to use dashboard can help with issues including deployment planning, load balancing, automatic VM migration, configuration management, and capacity diagnosis.

Virtualization offers advantages that include server consolidation, isolation, rapid provisioning, and improved change management processes. Since virtualization breaks the hardware dependency and isolates virtual machines from details about the physical servers on which they are hosted, virtual images can be moved from one hosting platform to another. They can also be cloned to create more virtual machines, as desired. One of the challenges with cloning virtual images is handling operating system, network, and application specific customization. This article provides a sample framework for automating virtual image activation on new host platforms. This article, along with a previous article on Using virtual image templates to deploy WebSphere Application Server, demonstrates an automated approach for quickly and easily provisioning new WebSphere Application Server environments. The sample deployment and activation code included with this article is independent of WebSphere Application Server and can be used in conjunction with other software inside a virtual image. The specific example provided here is for WebSphere Application Server V6 in VMware or XEN virtual images, using SUSE V10 as the guest operating system. The activation techniques described in this article can be used in conjunction with IBM Tivoli® Provisioning Manager as described in Using Tivoli Provisioning Manager to deploy composite virtual appliances.

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.

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.

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.

If you have a server with more than 4GB RAM and want to install a 32bit Debian Etch on it (following this tutorial: Debian Etch And Xen From The Debian Repository), you'd expect the Xen-PAE kernel to see all your RAM because the Xen-PAE kernel supports up to 64GB RAM. In fact, it recognizes only about 3.3GB RAM due to a bug in the GRUB bootloader. This article explains how you can fix GRUB so that all your RAM gets recognized. I do not issue any guarantee that this will work for you!

The Enomalism Virtualized Management Dashboard (VMD) is a powerful web-based virtual server manager. Designed to answer the complexity of managing globally disperse virtual server environments. Enomalism helps to ease the transition to a virtualized environment by reducing an IT organizations overall workload. The easy to use dashboard can help with issues including deployment planning, load balancing, automatic VM migration, configuration management, and capacity diagnosis.

dtc-xen: brings a full Xen control panel to your Xen server by connecting a DTC panel to it

XenMan is an intuitive, graphical management tool aimed at operational lifecycle management for the Xen virtualization platform. XenMan is built on the firm design philosophy that ease-of-use and sophistication can, and should, co-exist in a single management tool. So, XenMan should hopefully prove valuable to both seasoned Xen Administrators as well as those just seeking an introduction to Xen Virtualization. With XenMan's secure, multi-node capabilities, administrators can safely manage their entire environment from a single, centralized console. Most common administrative tasks like starting/stopping/provisioning virtual machines (Guest OS's) typically involve just a few mouse clicks with XenMan; as do server management operations like scanning OS configurations or acquiescing individual servers for maintainance.