Here are some sites that I have been reading.

http://www.virtuatopia.com/index.php/An_Overview_of_Virtualization_Techniques

http://www.howtoforge.com/installing-xen-on-centos-5.2-i386

http://www.howtoforge.com/centos_5.0_xen

http://wiki.centos.org/HowTos/KVM

http://wiki.kartbuilding.net/index.php/Xen_Networking

Part of this Howto will have been plagerised from these sourses.

Will my hardware work?

For Intel CPUs:

grep vmx /proc/cpuinfo

For AMD CPUSs:

grep svm /proc/cpuinfo

If neither of the above command produce output then it is likely these features are unavailable and that your hardware is unable to run Xen HVM guests. Whilst you can still run modified operating systems (such as Linux) as paravirtualized guests you will not be able to virtualize Windows using Xen. It is also possible that the host CPU supports one of these features, but that the functionality is disabled by default in the system BIOS. To verify this, access the host system’s BIOS configuration menu during the boot process and look for an option related to virtualization support. If such an option exists and is disabled, enable it, boot the system and repeat the above commands.

I have choosen the route to only use hardware that supports cirtulisation, makes my life easier and keeps all options open.

After this it was a very simple matter of installing a virtual XP VM.

Having created the VM and got it running I want the following sernaio:

Configuration files

vi /etc/xen/xend-config.sxp
(network-script network-bridge)
#(network-script network-nat)
#(network-script network-route) 

(vif-script vif-bridge)
#(vif-script vif-nat)
#(vif-script vif-route)

Configure vm01.cfg (vm config file)

vi /etc/xen/auto/vm01.cfg
vif  = [ 'ip=192.168.0.6' ]
#thats all that is required for the networking part.




/etc/libvirt/qemu/networks/autostart/default.xlm

After changing settings for default.xml, the interface virbro still has the old IP address, not the new one. This was still true after running the following:

/etc/init.d/network restart
/etc/init.d/libvirtd restart

Working with virch (kind of like bash for virtulisation)

virsh # help
Commands:

 help            print help
 attach-device   attach device from an XML file
 attach-disk     attach disk device
 attach-interface attach network interface
 autostart       autostart a domain
 capabilities    capabilities
 cd              change the current directory
 connect         (re)connect to hypervisor
 console         connect to the guest console
 cpu-baseline    compute baseline CPU
 cpu-compare     compare host CPU with a CPU described by an XML file
 create          create a domain from an XML file
 start           start a (previously defined) inactive domain
 destroy         destroy a domain
 detach-device   detach device from an XML file
 detach-disk     detach disk device
 detach-interface detach network interface
 define          define (but don't start) a domain from an XML file
 domid           convert a domain name or UUID to domain id
 domuuid         convert a domain name or id to domain UUID
 dominfo         domain information
 domjobinfo      domain job information
 domjobabort     abort active domain job
 domname         convert a domain id or UUID to domain name
 domstate        domain state
 domblkstat      get device block stats for a domain
 domifstat       get network interface stats for a domain
 dommemstat      get memory statistics for a domain
 domblkinfo      domain block device size information
 domxml-from-native Convert native config to domain XML
 domxml-to-native Convert domain XML to native config
 dumpxml         domain information in XML
 edit            edit XML configuration for a domain
 find-storage-pool-sources discover potential storage pool sources
 find-storage-pool-sources-as find potential storage pool sources
 freecell        NUMA free memory
 hostname        print the hypervisor hostname
 list            list domains
 migrate         migrate domain to another host
 migrate-setmaxdowntime set maximum tolerable downtime
 net-autostart   autostart a network
 net-create      create a network from an XML file
 net-define      define (but don't start) a network from an XML file
 net-destroy     destroy a network
 net-dumpxml     network information in XML
 net-edit        edit XML configuration for a network
 net-list        list networks
 net-name        convert a network UUID to network name
 net-start       start a (previously defined) inactive network
 net-undefine    undefine an inactive network
 net-uuid        convert a network name to network UUID
 iface-list      list physical host interfaces
 iface-name      convert an interface MAC address to interface name
 iface-mac       convert an interface name to interface MAC address
 iface-dumpxml   interface information in XML
 iface-define    define (but don't start) a physical host interface from an XML file
 iface-undefine  undefine a physical host interface (remove it from configuration)
 iface-edit      edit XML configuration for a physical host interface
 iface-start     start a physical host interface (enable it / "if-up")
 iface-destroy   destroy a physical host interface (disable it / "if-down")
 managedsave     managed save of a domain state
 nodeinfo        node information
 nodedev-list    enumerate devices on this host
 nodedev-dumpxml node device details in XML
 nodedev-dettach dettach node device from its device driver
 nodedev-reattach reattach node device to its device driver
 nodedev-reset   reset node device
 nodedev-create  create a device defined by an XML file on the node
 nodedev-destroy destroy a device on the node
 nwfilter-define define or update a network filter from an XML file
 nwfilter-undefine undefine a network filter
 nwfilter-dumpxml network filter information in XML
 nwfilter-list   list network filters
 nwfilter-edit   edit XML configuration for a network filter
 pool-autostart  autostart a pool
 pool-build      build a pool
 pool-create     create a pool from an XML file
 pool-create-as  create a pool from a set of args
 pool-define     define (but don't start) a pool from an XML file
 pool-define-as  define a pool from a set of args
 pool-destroy    destroy a pool
 pool-delete     delete a pool
 pool-dumpxml    pool information in XML
 pool-edit       edit XML configuration for a storage pool
 pool-info       storage pool information
 pool-list       list pools
 pool-name       convert a pool UUID to pool name
 pool-refresh    refresh a pool
 pool-start      start a (previously defined) inactive pool
 pool-undefine   undefine an inactive pool
 pool-uuid       convert a pool name to pool UUID
 secret-define   define or modify a secret from an XML file
 secret-dumpxml  secret attributes in XML
 secret-set-value set a secret value
 secret-get-value Output a secret value
 secret-undefine undefine a secret
 secret-list     list secrets
 pwd             print the current directory
 quit            quit this interactive terminal
 exit            quit this interactive terminal
 reboot          reboot a domain
 restore         restore a domain from a saved state in a file
 resume          resume a domain
 save            save a domain state to a file
 schedinfo       show/set scheduler parameters
 dump            dump the core of a domain to a file for analysis
 shutdown        gracefully shutdown a domain
 setmem          change memory allocation
 setmaxmem       change maximum memory limit
 setvcpus        change number of virtual CPUs
 suspend         suspend a domain
 ttyconsole      tty console
 undefine        undefine an inactive domain
 update-device   update device from an XML file
 uri             print the hypervisor canonical URI
 vol-create      create a vol from an XML file
 vol-create-from create a vol, using another volume as input
 vol-create-as   create a volume from a set of args
 vol-clone       clone a volume.
 vol-delete      delete a vol
 vol-wipe        wipe a vol
 vol-dumpxml     vol information in XML
 vol-info        storage vol information
 vol-list        list vols
 vol-pool        returns the storage pool for a given volume key or path
 vol-path        returns the volume path for a given volume name or key
 vol-name        returns the volume name for a given volume key or path
 vol-key         returns the volume key for a given volume name or path
 vcpuinfo        domain vcpu information
 vcpupin         control domain vcpu affinity
 version         show version
 vncdisplay      vnc display
 snapshot-create Create a snapshot
 snapshot-current Get the current snapshot
 snapshot-delete Delete a domain snapshot
 snapshot-dumpxml Dump XML for a domain snapshot
 snapshot-list   List snapshots for a domain
 snapshot-revert Revert a domain to a snapshot

The configuration I am looking for