Planet Hypervisor

VM Backup with Xen Orchestra

As you may already know, we planned to integrate backups directly in Xen Orchestra: this feature is in our current road map. The goal is to provide a simple interface to select, plan and automatize all your VMs backups. But, until its done, one of our clients needs quickly a way to snapshot all its […]

Colored diffs with mutt

I cannot stand reviewing patches with gmail or any GUI e-mail client. I use mutt. On my last post I explained how you can apply patches directly from within mutt onto a git tree with a few shortcuts without leaving the terminal. This small post provides the next step to allow you to grow a mustache... I mean, get you to enjoy your mutt experience even more when reviewing patches by getting you colored diffs to match the same colors provided to you by good 'ol 'git diff'. Edit your .muttrc file and add these.# Patch syntax highlighting                                                     color   normal ...

In-memory read caching for XenServer

Overview In this blog post, I introduce a new feature of XenServer Creedence alpha.4, in-memory read caching, the technical details, the benefits it can provide, and how best to use it. Technical Details A common way of using XenServer is to have an OS image, which I will call the golden image, and many clones of this image, which I will call leaf images. XenServer implements cheap clones by linking images together in the form of a tree. When the VM accesses a sector in the disk, if a sector has been written into the leaf image, this data is retrieved from that...

Mirage OS v2.0: The new features

The first release of Mirage OS back in December 2013 introduced the prototype of the unikernel concept, which realised the promise of a safe, flexible mechanism to build highly optimized software stacks purpose-built for deployment in the public cloud (see the overview of Mirage OS for some background). Since then, we’ve been hard at work [...]

Mirage v2.0: a recap of the new features

The first release of Mirage back in December 2013 introduced the prototype of the unikernel concept, which realised the promise of a safe, flexible mechanism to build highly optimized software stacks purpose-built for deployment in the public cloud (more background on this). Since then, we've been hard at work using and extending Mirage for real projects and the community has been steadily growing. We're thrilled to announce the release of Mirage OS v2.0 today! Over the past few weeks the team has been hard at work blogging about all the new features in this latest release, coordinated by the tireless...

Building an ARMy of Xen unikernels

Mirage has just gained the ability to compile unikernels for the Xen/arm32 platform, allowing Mirage guests to run under the Xen hypervisor on ARM devices such as the Cubieboard 2 and CubieTruck. Introduction The ARMv7 architecture introduced the (optional) Virtualization Extensions, providing hardware support for running virtual machines on ARM devices, and Xen's ARM Hypervisor uses this to support hardware accelerated ARM guests. Mini-OS is a tiny OS kernel designed specifically for running under Xen. It provides code to initialise the CPU, display messages on the console, allocate memory (malloc), and not much else. It is used as the low-level core of Mirage's Xen implementation. Mirage...

sunxi-tools now available in Debian

I've recently packaged the sunxi tools for Debian. These are a set of tools produce by the Linux Sunxi project for working with the Allwinner "sunxi" family of processors. See the package page for details. Thanks to Steve McIntyre for sponsoring the initial upload. The most interesting component of the package are the tools for working with the Allwinner processors' FEL mode. This is a low-level processor mode which implements a simple USB protocol allowing for initial programming of the device and recovery which can be entered on boot (usually be pressing a special 'FEL button' somewhere on the device). It is thanks to FEL mode that most sunxi based devices are pretty much...

Using Irmin to add fault-tolerance to the Xenstore database

This is the second in a series of posts that introduces the Irmin distributed storage engine. You might like to begin with the introductory post. Xenstore is a critical service found on all hosts running Xen. Xenstore is necessary to configure all VM I/O devices such as disk controllers and network interface cards; share performance statistics and OS version information; and signal VMs during shutdown, suspend, resume, migrate etc. Xenstore must be reliable: if it fails then the host is unmanageable and must be rebooted. Xenstore must be secure: if it is compromised by a VM then that VM...

Running Scientific Linux Guest VMs on XenServer

What is Scientific Linux? In short, Scientific Linux is an customized RedHat/CentOS Linux distribution provided by CERN and Fermilab: popular in educational institutions as well as laboratory environments.  More can be read about Scientific Linux here: https://www.scientificlinux.org/ From my own long-term testing - before XenServer 6.2 and our pre-release/Alpha - Creedence - I have ran both Scientific Linux 5 and Scientific Linux 6 without issues.  This article's scope is to show how one can install Scientific Linux and, more specifically, ensure the XenTools Guest Additions for Linux are installed as these do not require any form of "Xen-ified" kernel. XenServer and Creedence The following...

Off to OSCON ....

This week is OSCON, and I'm looking forward to my first year there as the official community manager for XenServer. In fact, it was at OSCON 2013 that I tentatively accepted the position and transitioned from a purely commercial Citrix CloudPlatform and XenServer focus to one where the platform, users and install-base matter most. It's been an interesting year and while we've not accomplished everything I'd have liked, we've made some significant strides forward. The most significant of which has to be the platform refresh, performance improvements and the alpha program we're currently running. So whether you like XenServer, think...