################################ __ __ _____ ___ \ \/ /___ _ __ |___ / / _ \ \ // _ \ '_ \ |_ \| | | | / \ __/ | | | ___) | |_| | /_/\_\___|_| |_| |____(_)___/ ################################ http://www.xensource.com/xen/about.html What is Xen? ============ Xen is a Virtual Machine Monitor (VMM) originally developed by the Systems Research Group of the University of Cambridge Computer Laboratory, as part of the UK-EPSRC funded XenoServers project. Xen is freely-distributable Open Source software, released under the GNU GPL. Since its initial public release, Xen has grown a large development community, spearheaded by XenSource Inc, a company created by the original Xen development team to build enterprise products around Xen. The 3.0 release offers excellent performance, hardware support and enterprise-grade features such as x86_32-PAE, x86_64, SMP guests and live relocation of VMs. This install tree contains source for a Linux 2.6 guest; ports to Linux 2.4, NetBSD, FreeBSD and Solaris will follow later (and are already available for previous Xen releases). This file contains some quick-start instructions to install Xen on your system. For full documentation, see the Xen User Manual. If this is a pre-built release then you can find the manual at: dist/install/usr/share/doc/xen/pdf/user.pdf If you have a source release, then 'make -C docs' will build the manual at docs/pdf/user.pdf. Quick-Start Guide - Pre-Built Binary Release ============================================ [NB. Unless noted otherwise, all the following steps should be performed with root privileges.] 1. Install the binary distribution onto your filesystem: # sh ./install.sh Among other things, this will install Xen and Xen-ready Linux kernel files in /boot, kernel modules and Python packages in /lib, and various control tools in standard 'bin' directories. 2. Configure your bootloader to boot Xen and an initial Linux virtual machine. Note that Xen currently only works with GRUB and pxelinux derived boot loaders: less common alternatives such as LILO are *not* supported. You can most likely find your GRUB menu file at /boot/grub/menu.lst: edit this file to include an entry like the following: title Xen 3.0 / XenLinux 2.6 kernel /boot/xen-3.0.gz console=vga module /boot/vmlinuz-2.6-xen root= ro console=tty0 module /boot/initrd-2.6-xen.img NB: Not all kernel configs need an initial ram disk (initrd), but if you do specify one you'll need to use the 'module' grub directive rather than 'initrd'. The linux command line takes all the usual options, such as root= to specify your usual root partition (e.g., /dev/hda1). The Xen command line takes a number of optional arguments described in the manual. The most common is 'dom0_mem=xxxM' which sets the amount of memory to allocate for use by your initial virtual machine (known as domain 0). Note that Xen itself reserves about 32MB memory for internal use, which is not available for allocation to virtual machines. 3. Reboot your system and select the "Xen 3.0 / XenLinux 2.6" menu option. After booting Xen, Linux will start and your initialisation scripts should execute in the usual way. Quick-Start Guide - Source Release ================================== First, there are a number of prerequisites for building a Xen source release. Make sure you have all the following installed, either by visiting the project webpage or installing a pre-built package provided by your Linux distributor: * GCC (preferably v3.2.x or v3.3.x; older versions are unsupported) * GNU Make * GNU Binutils * Development install of zlib (e.g., zlib-dev) * Development install of Python v2.3 or later (e.g., python-dev) * Development install of curses (e.g., libncurses-dev) * bridge-utils package (/sbin/brctl) * iproute package (/sbin/ip) * hotplug or udev [NB. Unless noted otherwise, all the following steps should be performed with root privileges.] 1. Download and untar the source tarball file. This will be a file named xen-unstable-src.tgz, or xen-$version-src.tgz. You can also pull the current version from the SCMS that is being used (Bitkeeper, scheduled to change shortly). # tar xzf xen-unstable-src.tgz Assuming you are using the unstable tree, this will untar into xen-unstable. The rest of the instructions use the unstable tree as an example, substit .configs and build trees, perform the following steps: # make world # make install This will create and install onto the local machine. It will build the xen binary (xen.gz), and a linux kernel and modules that can be used in both dom0 and an unprivileged guest kernel (vmlinuz-2.6.x-xen), the tools and the documentation. You can override the destination for make install by setting DESTDIR to some value. The make command line defaults to building the kernel vmlinuz-2.6.x-xen. You can override this default by specifying KERNELS=kernelname. For example, you can make two kernels - linux-2.6-xen0 and linux-2.6-xenU - which are smaller builds containing only selected modules, intended primarily for developers that don't like to wait for a full -xen kernel to build. The -xenU kernel is particularly small, as it does not contain any physical device drivers, and hence is only useful for guest domains. To make these two kernels, simply specify KERNELS="linux-2.6-xen0 linux-2.6-xenU" in the make command line. If you want to build an x86_32 PAE capable xen and kernel to work on machines with >= 4GB of memory, use XEN_TARGET_X86_PAE=y on the make command line. 4. To rebuild an existing tree without modifying the config: # make dist This will build and install xen, kernels, tools, and docs into the local dist/ directory. You can override the destination for make install by setting DISTDIR to some value. make install and make dist differ in that make install does the right things for your local machine (installing the appropriate version of hotplug or udev scripts, for example), but make dist includes all versions of those scripts, so that you can copy the dist directory to another machine and install from that distribution. 5. To rebuild a kernel with a modified config: # make linux-2.6-xen-config CONFIGMODE=menuconfig (or xconfig) # make linux-2.6-xen-build # make linux-2.6-xen-install Depending on your config, you may need to use 'mkinitrd' to create an initial ram disk, just like a native system e.g. # depmod 2.6.16-xen # mkinitrd -v -f --with=aacraid --with=sd_mod --with=scsi_mod initrd-2.6.16-xen.img 2.6.16-xen