Tag Archives: Virtualization

Paravirtulization with Citrix XenServer 5.5 and Ubuntu 9.10

Publicat la 25 January 2013 1 comentariu

Few days ago I had a task to P2V an old Ubuntu 9.10 machine. The P2V process was very easy and went smooth. The challenge was how to get this VM paravirtualized. After reading on the net how others have done this and what problems they had, I managed to finish my task pretty quick. Anyway... I hope maybe this post helps someone - definitely will help me if I will have to do this task again.

This post describes with simple step-by-step instructions how to install Ubuntu 9.10 VM as a paravirtualized virtual machine on a Citrix XenServer 5.5.

Creating Our Guest Ubuntu VM
Our first step is to get an Ubuntu VM installed as a typical HVM. You can find many different options on the web about partitioning and recommended partition sizes. A default installation of Ubuntu 9.10 will install on two partitions:

  • a root (/) partition, which includes the boot system (/boot), and
  • a swap partition.

For this article I installed Ubuntu with default partition options.

Configuring XenServer

First login on XenServer console.

Get UUID for the new created VM.

[codesyntax lang="bash"]

xe vm-list name-label="ubuntu-vm" params=uuid --minimal

[/codesyntax]

ed788e42-aabd-f78e-180a-5e46ec8b2465

Find the VM’s hard drive, known as a virtual block device (VBD):

[codesyntax lang="bash"]

xe vm-disk-list uuid=ed788e42-aabd-f78e-180a-5e46ec8b2465

[/codesyntax]

Disk 0 VBD:
uuid ( RO)             : ceb500b7-b154-2251-2fcd-5de05da50368
    vm-name-label ( RO): ubuntu10.04
       userdevice ( RW): 0

Mark the VBD as bootable:

[codesyntax lang="bash"]

xe vbd-param-set uuid=ceb500b7-b154-2251-2fcd-5de05da50368 bootable=true

[/codesyntax]

We don't want our VM to run as HVM:

[codesyntax lang="bash"]

xe vm-param-set uuid=ed788e42-aabd-f78e-180a-5e46ec8b2465 HVM-boot-policy=
xe vm-param-set uuid=ed788e42-aabd-f78e-180a-5e46ec8b2465 PV-bootloader=pygrub

[/codesyntax]

pygrub can’t handle grub2, so we have to manually set these parameters for paravirtualization:

[codesyntax lang="bash"]

xe vm-param-set uuid=ed788e42-aabd-f78e-180a-5e46ec8b2465 PV-bootloader-args="--kernel=/boot/vmlinuz-2.6.31-14-generic --ramdisk=/boot/initrd.img-2.6.31-14-generic"
xe vm-param-set uuid=ed788e42-aabd-f78e-180a-5e46ec8b2465 PV-args="root=UUID=706a70b4-09ee-4682-8f08-c8eb79ddd410 ro quiet"

[/codesyntax]

Notes:

  • 706a70b4-09ee-4682-8f08-c8eb79ddd410 - UUID for the bootable partition. You can find it in grub configuration file or using blkid command
  • if you have a separate partition for boot then you will have to change kernel and ramdisk parameters to --kernel=/vmlinuz-2.6.31-14-generic --ramdisk=/initrd.img-2.6.31-14-generic

Close and restart your XenCenter client (it appears to be a bit buggy and doesn’t let you type into the new console until it’s restarted), and boot up your VM (which will now start in PV mode).

Install XenServer tools

Attach the XenServer tools ISO image (xs-tools.iso) and mount the CD on your VM.

[codesyntax lang="bash"]

mount /dev/cdrom /mnt

[/codesyntax]

Install XenServer tools

[codesyntax lang="bash"]

dpkg -i /mnt/Linux/xe-guest-utilities_5.5.0-466_amd64.deb

[/codesyntax]

During the install, you would have likely noticed a couple errors, specifically:

update-rc.d: warning: xe-linux-distribution start runlevel arguments (S) do not match LSB Default-Start values (2 3 4 5)
...
[: 31: configure: unexpected operator

The package was build for Debian, not for Ubuntu so we don't have to worry about error message. We need to adjust the default start/kill runlevels.

[codesyntax lang="bash"]

update-rc.d -f xe-linux-distribution remove
update-rc.d xe-linux-distribution defaults

[/codesyntax]

Since now we are paravirtualized, XenServer will want to use HVC0, not the traditionally TTY.

[codesyntax lang="bash"]

sed -e "s/tty1/hvc0/ig" /etc/init/tty1.conf | sudo bash -c 'cat > /etc/init/hvc0.conf'

[/codesyntax]

Accessing GUI on ubuntu paravirtualized VM

If you try and start the GUI on a paravirtualized Ubuntu VM in XenServer, you’ll get the following error:

Primary device is not PCI
(EE) open /dev/fb0: No such file or directory
(EE) No devices detected

In a paravirtualized world there is no such thing as a physical console (nor is there a physical CPU, physical memory etc). Hence for completely paravirtualized OSes (with a paravirtualized kernel like Xen) there’s no GUI console.

In other words, use VNC for now:

Install VNC
[codesyntax lang="bash"]

apt-get install vnc4server

[/codesyntax]

Set the VNC resolution (whatever resolution you want to see on your desktop machine you’ll be using the VNC client on
[codesyntax lang="bash"]

vncserver -geometry 1280x1024 -depth 24

[/codesyntax]

Create a password and VNC server should create some configuration files and start up.

Now we need to edit one of the configuration files

[codesyntax lang="bash"]

vncserver -kill :1

[/codesyntax]

[codesyntax lang="bash"]

vim ~/.vnc/xstartup

[/codesyntax]

#!/bin/sh
# Uncomment the following two lines for normal desktop:
unset SESSION_MANAGER
exec sh /etc/X11/xinit/xinitrc

[ -x /etc/vnc/xstartup ] && exec /etc/vnc/xstartup
[ -r $HOME/.Xresources ] && xrdb $HOME/.Xresources
xsetroot -solid grey
vncconfig -iconic &
x-terminal-emulator -geometry 1280x1024+10+10 -ls -title “$VNCDESKTOP Desktop” &
x-window-manager &
[codesyntax lang="bash"]

:wq

[/codesyntax]

Start up the VNC server again
[codesyntax lang="bash"]

vncserver -geometry 1280x1024 -depth 24

[/codesyntax]

Troubleshooting

Can't type at login prompt.

I ran into one instance where I could see the login prompt but nothing I typed appeared.  First, make sure you click inside the console window.  If that does not resolve the issue, close and reopen XenCenter.  This fixed the issue when I encountered it.

PV is not working and I need to get the VM back up.

[codesyntax lang="bash"]

xe vm-param-set uuid= HVM-boot-policy="BIOS order"

[/codesyntax]

To return to PV mode, clear the HVM-boot-policy parameter.

[codesyntax lang="bash"]

xe vm-param-set uuid= HVM-boot-policy=

[/codesyntax]

Please note that HVM-boot-policy parameter IS case sensitive.

Links:
http://www.aikidokatech.com/?p=30
http://blog.403labs.com/post/1546501840/paravirtulization-with-citrix-xenserver-5-5-and-ubuntu
http://sysadmin.circularvale.com/server-config/accessing-a-gui-on-ubuntu-xenserver-vm/

Autostart VM in free version of XenServer 6.x

Publicat la 23 December 2012 5 comentarii

Unlike previous versions, VMs do not have a visible property in the GUI allowing autostart, which kinda sucks big time. This has been claimed to interfere with High Availability (HA) and produced unexpected results during HA functions.

So, what we are going to do?!

First approach is to set auto_poweron parameter to true at the pool and VM level.

Setting the XenServer to allow Auto-Start
1. Gather the UUID’s of the pools you wish to auto-start.
To get the list of the pool’s on your XenServer type

[codesyntax lang="bash"]

xe pool-list

[/codesyntax]
2. Copy the UUID of the pool. If you have just one server, it will still have a pool UUID as bellow:

uuid ( RO)                : d170d718-e0de-92fc-b920-f4c59cc62e91
          name-label ( RW):
    name-description ( RW):
              master ( RO): 755d4ea3-373b-44b9-8ae3-3cd6f77a7f33
          default-SR ( RW): 51218f44-6ac6-4893-98fb-f924b08f7af9

3. Set the pool or server to allow auto-start:

[codesyntax lang="bash"]

xe pool-param-set uuid=UUID other-config:auto_poweron=true

[/codesyntax]
Note: *Replacing UUID with the UUID of the XenServer or pool.

Setting the Virtual Machines to Auto-Start
1. Gather the UUID’s of the Virtual Machine you want to auto-start by typing:
[codesyntax lang="bash"]

xe vm-list

[/codesyntax]

Note: This generates a list of Virtual Machines in your pool or server and their associated UUID’s.

2. Copy the UUID of the Virtual Machines you want to auto-start, and type the following command for each Virtual Machine to auto-start:
[codesyntax lang="bash"]

xe vm-param-set uuid=UUID other-config:auto_poweron=true

[/codesyntax]

Note: *Replace UUID with the UUID of the Virtual Machine to auto-start.*

For this second part (enabling auto-start for the VMs) we can use a little one-line script, which would enable autostart for ALL vms:

[codesyntax lang="bash"]

for i in `xe vm-list is-control-domain=false –minimal | tr , ‘  ’`; do xe vm-param-set uuid=$i other-config:auto_poweron=true; done

[/codesyntax]

Edit rc.local file to start all vms with "auto_poweron" in their other-config

Add the following lines at the end of /etc/rc.local file:

[ -e /proc/xen ] || exit 0

XAPI_START_TIMEOUT_SECONDS=240

# wait for xapi to complete initialisation for a max of XAPI_START_TIMEOUT_SECONDS
/opt/xensource/bin/xapi-wait-init-complete ${XAPI_START_TIMEOUT_SECONDS}

if [ $? -eq 0 ]; then

pool=$(xe pool-list params=uuid --minimal 2> /dev/null)

auto_poweron=$(xe pool-param-get uuid=${pool} param-name=other-config param-key=auto_poweron 2> /dev/null)
if [ $? -eq 0 ] && [ "${auto_poweron}" = "true" ]; then
logger "$0 auto_poweron is enabled on the pool-- this is an unsupported configuration."

# if xapi init completed then start vms (best effort, don't report errors)
xe vm-start other-config:auto_poweron=true power-state=halted --multiple >/dev/null 2>/dev/null || true
fi
fi

Second approach is to use vApp

1. Create vApp
2. Choose vms to vApp
3. Choose boot order and delays between starts
4. To get uuid of vApp use:

[codesyntax lang="bash"]

xe appliance-list name-label="name-vapp"

[/codesyntax]

5. Edit rc.local file to start vApp:

[codesyntax lang="bash"]

echo "sleep 40" >> /etc/rc.local
echo "xe appliance-start uuid=uuid-vapp" >> /etc/rc.local

[/codesyntax]
7. Save file, reboot XenServer

Links:
http://support.citrix.com/article/CTX133910
http://run.tournament.org.il/citrix-xenserver-6-0-enable-vm-autostart/
http://blog.wallenqvist.se/2012/06/04/371/
http://forums.citrix.com/message.jspa?messageID=1677077#1677077
https://github.com/xen-org/xen-api/tree/master/scripts