Xen support is available for increasingly many operating systems:
right now, Linux 2.4, Linux 2.6 and NetBSD are available for Xen 2.0.
We expect that Xen support will ultimately be integrated into the
-official releases of Linux, NetBSD, FreeBSD and Dragonfly BSD.
-Other OS ports, including Plan 9, are in progress.
+official releases of Linux, NetBSD and FreeBSD. Other OS ports,
+including Plan 9, are in progress.
Possible usage scenarios for Xen include:
\begin{description}
\item [Cluster computing.] Management at VM granularity provides more
flexibility than separately managing each physical host, but
better control and isolation than single-system image solutions.
-\item [Hardware support for custom OSes.] Allow devlopment of new OSes
- while benefitting from the wide-ranging hardware support of
+\item [Hardware support for custom OSes.] Allow development of new OSes
+ while benefiting from the wide-ranging hardware support of
existing OSes such as Linux.
\end{description}
information along with pointers to papers and technical reports:
{\small {\tt http://www.cl.cam.ac.uk/xeno}}
-Xen has since grown into a fully-fledgd project in its own right,
+Xen has since grown into a fully-fledged project in its own right,
enabling us to investigate interesting research issues regarding the
best techniques for virtualising resources such as the CPU, memory,
disk and network. The project has been bolstered by support from
{\tt http://xen.sf.net}
\end{quote}
-\subsection{Using Bitkeeper}
+\subsection{Using BitKeeper}
If you wish to install Xen from a clone of our latest BitKeeper
repository then you will need to install the BitKeeper tools.
\begin{quote}
{\tt bk://xen.bkbits.net/xen-2.0.bk}
\end{quote}
-You can use Bitkeeper to
+You can use BitKeeper to
download it and keep it updated with the latest features and fixes.
Change to the directory in which you want to put the source code, then
If you have an existing Linux kernel configuration that you would like
to use for domain 0, you should copy it to
\path{dist/install/boot/config-2.6.9-xen0}; for example, certain
-distributions require a kernel with either {\tt udev} or {\tt devfs}
-support at boot time. During the first build, you may be prompted with
-some Xen-specific options. We advise accepting the defaults for
-these options.
+distributions require a kernel with {\tt devfs} support at boot time.
+During the first build, you may be prompted with some Xen-specific
+options. We advise accepting the defaults for these options.
%% \framebox{\parbox{5in}{
%% {\bf Distro specific:} \\
be passed to it (these are standard Linux parameters, identifying the
root device and specifying it be initially mounted read only and
instructing that console output be sent both to the screen and to the
-serial port). Some distributions such as SUSE do not require the
+serial port). Some distributions such as SuSE do not require the
{\small {\tt ro}} parameter.
%% \framebox{\parbox{5in}{
{\tt mv /lib/tls.disabled /lib/tls}}).
The reason for this is that the current TLS implementation uses
-segmentation in a way that is not permissable under Xen. If TLS is
+segmentation in a way that is not permissible under Xen. If TLS is
not disabled, an emulation mode is used within Xen which reduces
performance substantially and is not guaranteed to work perfectly.
What follows should look much like a conventional Linux boot. The
first portion of the output comes from Xen itself, supplying low level
information about itself and the machine it is running on. The
-following portion of the output comes from XenLinux itself.
+following portion of the output comes from XenLinux.
You may see some errors during the XenLinux boot. These are not
necessarily anything to worry about --- they may result from kernel
to install the prerequisites described in Section~\ref{sec:prerequisites}
and the Xen control tools. The control tools are installed by entering
the tools subdirectory of the repository and typing \\
-\verb!# LINUX_SRC=/path/to/linux2.4/source make linux24! \\
+\verb!# make install! \\
-To start the control daemon, type \\ \verb!# xend start! \\ If you
-wish to start the daemon automatically, see the instructions in
+To start the \xend control daemon, type \\ \verb!# xend start! \\ If you
+wish the daemon to start automatically, see the instructions in
Section~\ref{s:xend}. Once the daemon is running, you can use the
{\tt xm} tool to monitor and maintain the domains running on your
system. This chapter provides only a brief tutorial: we provide full
fills in parts of this template.
Both of them can be found in \path{/etc/xen/}
+
\section{Editing \path{xmdefconfig}}
At minimum, you should edit the following
\begin{description}
\item[kernel] Set this to the path of the kernel you compiled for use
- with Xen. [e.g. {\tt kernel =
- '/root/xen-2.0.bk/install/boot/vmlinuz-2.4.27-xenU'}]
+ with Xen. [e.g. {\tt kernel = '/boot/vmlinuz-2.6.9-xenU'}]
\item[memory] Set this to the size of the domain's memory in
megabytes. [e.g. {\tt memory = 64} ]
\item[disk] Set the first entry in this list to calculate the offset
Ttylinux is a very small Linux distribution, designed to
require very few resources. We will use it as a concrete example of
how to start a Xen domain. Most users will probably want to install a
-more complex mainstream distribution once they have mastered the
+full-featured distribution once they have mastered the
basics.
\begin{enumerate}
The most important {\tt xm} commands are: \\
\verb_# xm list_ : Lists all domains running. \\
\verb_# xm consoles_ : Gives information about the domain consoles. \\
-\verb_# xm console_: open a console to a domain.
+\verb_# xm console_: Opens a console to a domain.
e.g. \verb_# xm console 1_ (open console to domain 1)
\subsection{\tt xm list}
\end{verbatim}
Here we can see the details for the ttylinux domain, as well as for
-domain 0 (which of course is always running). Note that the console
+domain 0 (which, of course, is always running). Note that the console
port for the ttylinux domain is 9605. This can be connected to by TCP
using a terminal program (e.g. {\tt telnet} or, better, {\tt
xencons}). The simplest way to connect is to use the {\tt xm console}
There will be a delay whilst the domain is moved to the destination
machine. During this time, the Xen migration daemon copies as much
information as possible about the domain (configuration, memory
-contents, etc.) to the destination host as possible. The domain is
+contents, etc.) to the destination host. The domain is
then stopped for a fraction of a second in order to update the state
on the destination machine with any changes in memory contents, etc.
The domain will then continue on the new machine having been halted
\subsection{Setting memory footprints from dom0}
-The machine administator can request that a domain alter its memory
+The machine administrator can request that a domain alter its memory
footprint using the {\tt xm balloon} command. For instance, we can
request that our example ttylinux domain reduce its memory footprint
to 32 megabytes.
is the amount of memory the domain is originally started with,
preventing the domain from ever growing beyond this size. To permit a
domain to grow beyond its original allocation or to prevent a domain
-you've shrunk from reclaiming the memory it reliquished, use the {\tt
+you've shrunk from reclaiming the memory it relinquished, use the {\tt
xm maxmem} command.
\chapter{Domain filesystem storage}
-It is possible to directly export any Linux block device to a virtual,
+It is possible to directly export any Linux block device in dom0 to
+another domain,
or to export filesystems / devices to virtual machines using standard
network protocols (e.g. NBD, iSCSI, NFS, etc). This chapter covers
some of the possibilities.
\begin{verbatim}
root = '/dev/nfs'
nfs_server = 'a.b.c.d' # Substitute the IP for the server here
-nfs_root = '/path/to/root' # Path to root FS on the server machine
+nfs_root = '/path/to/root' # Path to root FS on the server
\end{verbatim}
The domain will need network access at boot-time, so either statically
netmask}, {\tt gateway}, {\tt hostname}) or enable DHCP ({\tt
dhcp='dhcp'}).
-\section{LVM-backed virtual block devices}
+%% \section{LVM-backed virtual block devices}
-XXX Put some simple examples here - would be nice if an LVM user could
-contribute some, although obviously users would have to read the LVM
-docs to do advanced stuff.
+%% XXX Put some simple examples here - would be nice if an LVM user could
+%% contribute some, although obviously users would have to read the LVM
+%% docs to do advanced stuff.
\part{User Reference Documentation}
management tasks that can be done using the xm tool.
It can be started using:\\ \verb_# xensv start_ \\ and
-stopped using: \verb_# xensv stop_ \\ It will automatically start \xend
-if it is not already running.
+stopped using: \verb_# xensv stop_ \\
By default, Xensv will serve out the web interface on port 8080. This
can be changed by editing {\tt
For additional flexibility, it is also possible to include Python
scripting commands in configuration files. An example of this is the
-\path{xmexample} file in order to handle the {\tt vmid} variable.
+\path{xmexample2} file, which uses Python code to handle the {\tt
+vmid} variable.
%\part{Advanced Topics}
\begin{description}
\item[network:] This script is called whenever \xend is started or
-stopped to respectively initialize or tear down the Xen virtual
-network. In the default configuration initialization creates the
+stopped to respectively initialise or tear down the Xen virtual
+network. In the default configuration initialisation creates the
bridge `xen-br0' and moves eth0 onto that bridge, modifying the
routing accordingly. When \xend exits, it deletes the Xen bridge and
removes eth0, restoring the normal IP and routing configuration.
\begin{description}
\item[ctx\_allow]
- the context switch allowance is similar to the "quantum"
+ the context switch allowance is similar to the `quantum'
in traditional schedulers. It is the minimum time that
a scheduled domain will be allowed to run before being
pre-empted.
proportional share of the CPU that a domain receives. It
is set inversely proportionally to a domain's sharing weight.
\item[warp]
- the amount of ``virtual time'' the domain is allowed to warp
+ the amount of `virtual time' the domain is allowed to warp
backwards
\item[warpl]
the warp limit is the maximum time a domain can run warped for
\section{XenLinux Boot Options}
-In addition to the standard linux kernel boot options, we support:
+In addition to the standard Linux kernel boot options, we support:
\begin{description}
\item[xencons=xxx ] Specify the device node to which the Xen virtual
console driver is attached. The following options are supported:
dd if=/dev/zero of=/path/diskimage bs=1024k count=size_in_mbytes
dd if=/dev/zero of=/path/swapimage bs=1024k count=size_in_mbytes
\end{verbatim}\end{small}
- If you're going to use this filesystem / diskimage only as a
- `template' for other vm diskimages, something like 300 MB should
+ If you're going to use this filesystem / disk image only as a
+ `template' for other vm disk images, something like 300 MB should
be enough.. (of course it depends what kind of packages you are
planning to install to the template)
mkswap /path/swapimage
\end{verbatim}\end{small}
-\item Mount the diskimage for installation
+\item Mount the disk image for installation
\begin{small}\begin{verbatim}
mount -o loop /path/diskimage /mnt/disk
\end{verbatim}\end{small}
running {\small {\tt apt-get install debootstrap}}. Otherwise, it can be
downloaded from the Debian project website.
-\item Install debian base to the diskimage:
+\item Install Debian base to the disk image:
\begin{small}\begin{verbatim}
debootstrap --arch i386 sarge /mnt/disk \
http://ftp.<countrycode>.debian.org/debian
Logout
-\item Umount the diskimage
+\item Unmount the disk image
\begin{small}\begin{verbatim}
umount /mnt/disk
\end{verbatim}\end{small}
\item Create Xen 2.0 configuration file for the new domain. You can
- use the example-configurations coming with xen as a template.
+ use the example-configurations coming with Xen as a template.
Make sure you have the following set up:
\begin{small}\begin{verbatim}
There you can see the ID of the console: 26. You can also list
the consoles with {\small {\tt xm consoles}} (ID is the last two
- digits of the portnumber.)
+ digits of the port number.)
Attach to the console:
\end{verbatim}\end{small}
or by telnetting to the port 9626 of localhost (the xm console
- progam works better).
+ program works better).
\item Log in and run base-config
\chapter{Installing Xen / XenLinux on Redhat or Fedora Core}
-When using Xen / Xenlinux on a standard Linux distribution there are
+When using Xen / XenLinux on a standard Linux distribution there are
a couple of things to watch out for:
Note that, because domains>0 don't have any privileged access at all,
If you want to use a single root file system that works cleanly for
both domain 0 and unprivileged domains, a useful trick is to use
-different 'init' run levels. For example, on the Xen Demo CD we use
+different 'init' run levels. For example, use
run level 3 for domain 0, and run level 4 for other domains. This
enables different startup scripts to be run in depending on the run
level number passed on the kernel command line.
\item[Domain ID] A unique identifier for a {\bf domain},
analogous to a process ID in an operating
- system. Apart from domain
+ system.
\item[Full virtualisation] An approach to virtualisation which
requires no modifications to the hosted
projects / xen.git / commitdiff