Difference between revisions of "Xen installation"

Latest revision as of 16:30, 27 September 2019

Introduction

The section contains the instruction to install Xen hypervisor on platform x86-64. Furthermore, it contains the procedure for running a guest operating system (i.e., Windows OS) under Xen hypervisor.

Xen Installation procedure

The following installation procedure aims at installing Xen RELEASE-4.11.0 from source. It has been performed on the platform x86-64 with one of the following operating system:

• Ubuntu 16.04
• Ubuntu 18.04.1 LTS

Build Dependencies
Install the following packages:

 # apt update && apt dist-upgrade #update/upgrade the kernel
 # apt install build-essential
 # apt install bcc bin86 gawk bridge-utils iproute2 
 # apt install libcurl4 libcurl4-openssl-dev bzip2 module-init-tools transfig tgif
 # apt install texinfo texlive-latex-base texlive-latex-recommended texlive-fonts-extra texlive-fonts-recommended
 # apt install pciutils-dev mercurial
 # apt install make gcc libc6-dev zlib1g-dev python python-dev python-twisted 
 # apt install libncurses5-dev patch libsdl-dev libjpeg-dev
 # apt install libvncserver-dev
 # apt install iasl libbz2-dev e2fslibs-dev git-core uuid-dev 
 # apt install ocaml ocaml-findlib libx11-dev bison flex xz-utils libyajl-dev
 # apt install gettext libpixman-1-dev libaio-dev markdown pandoc
 # apt install libc6-dev-i386
 # apt install lzma lzma-dev liblzma-dev #for rombios
 # apt install libsystemd-dev xorriso

Retrieve the GRUB version
The Xen installation strictly depends on the installed Grub version: grub-pc or grub-efi. In order to retrieve the grub version, launch the following command:

 $ dpkg --get-selections | grep grub

Retrieve Xen source
Clone the Xen repository and switch to the chosen version (i.e., RELEASE 4.11):

 $ git clone https://github.com/xen-project/xen.git
 $ cd xen
 $ git checkout RELEASE-4.11.0 -b RELEASE-4.11.0

In the following part of the tutorial, we refer to the Xen repository path as $XENPATH.

Configure
Configure:

 $ $XENPATH/configure --enable-systemd

In case of Xen EFI, add the option --enable-targets=x86_64-pep as follows:

 $ $XENPATH/configure --enable-systemd --enable-targets=x86_64-pep

Build and install
Build all components (hypervisor, tools, docs, stubdomains, etc):

 $ cd $XENPATH
 $ make dist

Install (as root):

 # sudo make install

Enable the Xen services
Reload dynamic libraries:

 # sudo /sbin/ldconfig

Enable systemd Xen services:

 # sudo systemctl enable xen-qemu-dom0-disk-backend.service
 # sudo systemctl enable xen-init-dom0.service
 # sudo systemctl enable xenconsoled.service
 # sudo systemctl enable xenstored.service
 # sudo systemctl enable xendomains.service

Note that in case of error for enabling xendomains service, remove /etc/init.d/xendomains.

Configure grub
Modify the configuration to show the Grub menu. Change the following line from /etc/default/grub:

  GRUB_TIMEOUT_STYLE=hidden

by setting the following value:

  GRUB_TIMEOUT_STYLE=menu

In order to enable the Xen log messages on the serial port, add the following line:

  GRUB_CMDLINE_XEN="loglvl=all guest_loglvl=all com1=115200,8n1,0x3e8,5 console=com1,vga cpufreq=xen:performance max_cstate=0"

where:

• loglvl=all : set the logging level for Xen
• guest_loglvl=all : set the logging level for Xen guests
• com1=115200,8n1,0x3e8,5 : specifies the UART parameters
• console=com1,vga : specifies which console Xen should use
• cpufreq=xen:performance : sets the power management governor policy to performance
• max_cstate=0 : defines the power modes, called “C-states”, are permitted. Set the power mode to 0, implies that the CPU fully turned on

Update grub
Finally, update grub and reboot:

 # sudo udate-grub
 # sudo reboot

Example: Creating a Windows HVM (Hardware Virtualized) Guest

In order to create a Windows HVM (Hardware Virtualized) Guest, performs the following operations:

• Setup the LVM storage
• Setup Linux Bridge in order to attach guest machines to the external network
• Install Windows OS on the Xen HVM Guest
• Run Windows OS on the Xen HVM Guest

Setup LVM storage

LVM, Logical Volume Manager, allows Linux to manage block devices in a more abstract manner. LVM creates logical volumes within a volume group that can share the same physical storage, known as physical volume. The LVM setup process can be summarized as allocating a physical volume, creating a volume group on top of this, then creating logical volumes to store data.

Install LVM:

 # sudo apt-get install lvm2

Create a physical partition (if there none free) by using a partition manager (e.g., gparted). Create a physical volume associated with the physical partition (e.g., /dev/XenVolumeGroup):

 # sudo pvcreate /dev/XenVolumeGroup

Create a volume group, called vg0, using this physical volume:

 # sudo vgcreate vg0 /dev/XenVolumeGroup

Finally, create a new logical volume, named windows, of 50Gbytes size on the volume group vg0:

 # sudo lvcreate -n windows -L 50G vg0

Setup Linux Bridge for guest networking

In order to allow network access to the Xen guests, the Linux bridge package allows to create a virtual switch within Dom0. The switch will take packets from the virtual machines and forward them on to the physical network.

In order to install the Linux bridge package and its core component, launch the following command:

  # sudo apt-get install bridge-utils

In case of Linux bridge configured by DHCP, edit /etc/network/interfaces file as follows:

 auto xenbr0
 iface xenbr0 inet dhcp
    bridge_ports <your-network-interface>

where <your-network-interface> is the physical interface (e.g., eth0).

In case of static Linux bridge, edit /etc/network/interfaces file as follows:

 auto xenbr0
 iface xenbr0 inet static
   bridge_ports <your-network-interface>
   address <bridge-address>
   netmask 255.255.255.0
   gateway <gtw-address>
   broadcast <bcast-address>

where <your-network-interface> is the physical interface (e.g., eth0) and <bridge-address>, <bridge-address> and <bridge-address> are respectively the address assigned to the Linux bridge, the gateway address and the broadcast address.

Then, restart networking:

 # sudo service networking restart

In case of correct setup, the command brctl will show the bridge setup:

 $ brctl show
 
 bridge name     bridge id               STP enabled     interfaces
 xenbr0		8000.006065444af1	no      <your-network-interface>

Install Windows OS on the Xen HVM Guest

It follows an example of configuration file, referred to as windows.cfg to enable the installation of Windows on the logical volume.

 #Domain Name
 name="win"
 
 #Virtualization type 
 builder="hvm"
 
 #Initial memory allocation (MB)
 memory=4096
 
 #Number of virtual CPUs to use
 vcpus=2
 
 #Disk device to a domain
 disk=['file:/dev/XenVolumeGroup/windows,hda,w', 'file:/root/windows.iso,hdb:cdrom,r']
 #Order of disk boot devices: (a) floppy, (c) hard-disk, (n) network and (d) cd-rom 
 boot="d"
 
 #Networking
 vif=['type=ioemu, bridge=xenbr0']
 
 #Grahics: vnc/sdl
 vnc=1
 sdl=0
 
 #Domain behaviour
 on_poweroff="destroy"
 on_reboot="preserve"
 on_crash="preserve"
 
 #Other options
 stdvga=0
 usb=1
 usbdevice="tablet"
 ide0="noprobe"
 serial="pty"

Let us assume that the Windows iso is located in /root/windows.iso file. Then the configuration disk option will contain the reference to such file exported to the domain as hdb:cdrom device. Furthermore, the configuration disk option will contain reference to the logical volume /dev/XenVolumeGroup/windows exported to the domain as hda device. In order to launch the installer, the boot option will point to the cd-rom ISO installation (i.e., boot="d").

Launch the following command to start the guest:

 # sudo xl create windows.cfg

Since the vnc option is enabled in the configuration file, the VNC display should be available on default port 5900 of the Dom0 IP. Use a client application to connect to the VCN server (e.g., gvncviewer, Remmina and so forth).

 $ gvncviewer <dom0-ip-address>:5900

Then, proceed with Windows OS installation. At the end of installation, destroy the domain in order to prevent the booting from CD-ROM:

 # sudo xl destroy win

where win is the domain guest defined in the configuration file.

Run Windows OS on the Xen HVM Guest

After installing the Windows on the logical volume, change the boot line in the configuration file (i.e., windows.cfg)

  boot="c"

so that the domain will boot from the hard-disk (i.e., logical volume /dev/XenVolumeGroup/windows ).

Then, start the domain:

  $ xl create windows.cfg

and reconnect with VNC to have access to the Windows GUI.