Grant McWilliams

Note: This is not quite functional. Ubuntu is asking a few questions during the install and then ultimately failing. I would recommend using my other Ubuntu 12.04 tutorial using a preseed file to auto install.

Note: Updated to work with XCP 1.5b/1.6

Thanks goes out to Alastair Brunton for troubleshooting this tutorial for me.

Install Type

• Non-interactive
• Network boot
• Commandline
• Paravirtualized

Prerequisites

• XCP/Xenserver
• Access to Internet
• Working DHCP server
• Working DNS name resolution

Introduction

This tutorial was written in the spirit of my CentOS 6 VM (64 bit) automated installation on XCP howto. In this tutorial I create a disk, download a kernel, kickstart file and install Ubuntu using the kickstart file. This has proven very popular since you can't install a paravirtualized domain using an install disk. This has been a very nice installation howto because you don't have to download any install CD/DVDs and you could create VMs using nothing more than a commandline login. It's also very nice because it can be mirrored locally if you're doing a bunch of them just by rsyncing a Ubuntu mirror locally then downloading my files and editing them.

This tutorial isn't "debian pure" since I chose to use a kickstart file instead of a preseed file. I've created preseed files for doing automated installations of Ubuntu before but in this case I wanted this tutorial to be as close to the CentOS one as possible making it easier for me to maintain thus the kickstart file.

Note: Updated to work with XCP 1.5b/1.6

Install Type

• Non-interactive
• Network boot
• Commandline
• Paravirtualized

Prerequisites

• XCP/Xenserver
• Access to Internet
• Working DHCP server
• Working DNS name resolution

Introduction

In this tutorial I create a disk, download a kernel, preseed file and install Ubuntu using the preseed file. This has proven very popular since you can't install a paravirtualized domain using an install disk. This has been a very nice installation howto because you don't have to download any install CD/DVDs and you could create VMs using nothing more than a commandline login. It's also very nice because it can be mirrored locally if you're doing a bunch of them just by rsyncing a Ubuntu mirror locally then downloading my files and editing them.

I've been wanting to revive some equipment from the garage. I have some old dual Xeon machines that I picked up from a contract a while back. I also bought some "Designed for Google" dual CPU Xeon boards that I haven't used for anything. I've been using one of these boards in a server that's been running non-stop for probably 6 years and it's always been rock solid. Now that I'm documenting Xen Cloud Platform as part of the Xenapi Admin Project I wanted to put together a multi-host cloud using Xen Cloud Platform and it's best if your hosts match thus the renewed interest in getting this machine up and going.

However, there's been a few problems. 

1. The CPUs from the Google boards don't work in the ASUS boards due to different FSB
2. I only had three CPUs for four sockets
3. I was missing a heat sink too
4. They use DDR2 ECC Registered ram which isn't common
5. Intel should have their teeth kicked in for designing three (count them) different heat sink/fan designs for one socket.
6. I needed backplates for two CPUs, the ones that arrived had no spring clips
7. My replacement heatsink came with one spring clip
8. Only one retailer had spring clips

So I started by ordering a new copper heatsink because at the time I thought I could use the CPUs out of the Google boards.  The heatsink arrived with one spring clip, I needed two. After I realized that I couldn't use the CPUs from the Google boards I then ordered a new CPU.  Armed with a new CPU and heatsink I installed them only to find out that I needed a spring clip to keep the heat sink ON the CPU. Only one retailer even carried it so I ordered one.  Now if only I had a power supply strong enough to run the board. Back to the garage again. 

In the garage I found a brand new computer case which surprisingly also had a brand new Pentium D motherboard in it. More booty from contracts. I wasn't concerned with the Pentium D but it had a Sparkle Power 600 watt power supply... Score!! 

As of today I now have a dual Xeon server in a 4u case to match it's duplicate. I need to score some ddr2 ecc registered ram as it only has 2 GB in it. That crap is expensive so I went to Ebay and I have bids on a couple batches of 8GB. We'll see if I get them.

The board was too big for the case too. I had to get out the hacksaw and cut away at the drive cage so it would fit. and drill new holes in the side of the case to mount a fan for more direct airflow.

This board is a little interesting.  It has...

1. Two Ultra-SCSI 320 channels
2. A zero channel raid slot
3. 64 bit, 133 mhz PCI-X slots
4. 8x PCI Express slot
5. 133 MB/sec IDE
6. SATA2
7. 8 Dimm slots
8. 2 CPU sockets

The Xeons don't have VT in them so I'll only be able to paravirtualize but that's all I ever do anyway. However Xeon 7030s have VT and will fit the board if anyone has any they want to get rid of cheap.

A lot of this tutorial was stolen from the CentOS wiki - http://wiki.centos.org/HowTos/Xen/InstallingCentOSDomU. I've shortened it by quite a bit to make it easier.  I assume you know this already but you will need to be logged in as root or have root privileges in order to execute this tutorial.

Creating an Image

The first step is to create an image that will hold the domU virtual disk. Since this can just be a file filled with zeros, our usual friend dd comes in handy.  The following command will create a /srv/xen/centos5.img file of 11GB, although the actual data blocks are allocated in a lazy fashion meaning that the disk image doesn't actually take up the whole 11GB until you fill it up. This is referred to as a sparse file.

dd if=/dev/zero of=/srv/xen/centos5.img oflag=direct bs=1M seek=10240 count=1

Preparing the Xen configuration file for installation

Xen uses one configuration file per domain. The configuration for the domain will be slightly different during the installation, because we have to provide installation kernels, and possibly some boot parameters. Here we download the installation kernel, ramdisk and xen config file.

A lot of this tutorial was stolen from the CentOS wiki - http://wiki.centos.org/HowTos/Xen/InstallingCentOSDomU. I've shortened it by quite a bit to make it easier.  I assume you know this already but you will need to be logged in as root or have root privileges in order to execute this tutorial.

Creating an Image

The first step is to create an image that will hold the domU virtual disk. Since this can just be a file filled with zeros, our usual friend dd comes in handy.  The following command will create a /srv/xen/centos5.img file of 11GB, although the actual data blocks are allocated in a lazy fashion meaning that the disk image doesn't actually take up the whole 11GB until you fill it up. This is referred to as a sparse file.

dd if=/dev/zero of=/srv/xen/centos5.img oflag=direct bs=1M seek=10240 count=1

Note: I lost my original xen config files so I've created new ones here. I no longer have a xen system so I can't test them. Please let me know if the tutorial still works or not - Grant

Introduction

A lot of this tutorial was stolen from my CentOS 5 Installation which in turn was stolen from the CentOS wiki. I've shortened and updated it for installing a CentOS 6 DomU. I just copy and paste all the indented lines into a root terminal and voila! a CentOS VM.

1. Creating an Virtual Disk Image

The first step is to create an disk image that will act as the VM hard drive. The following command will create a 4 GB sparse disk image named /srv/xen/centos6.img. A sparse file is created in such a way that the disk image doesn't actually take up the whole 4GB until you fill it up. If you'd like a larger (11GB) disk image substitute seek=10240 into the following line. I make my VMs nice and small so I can move them around easier. Making a disk image larger or adding a second drive later is easier than making it smaller or taking a drive away.

dd if=/dev/zero of=/srv/xen/centos6.img oflag=direct bs=1M seek=3800 count=1

wget http://mirror.centos.org/centos/6/os/i386/isolinux/vmlinuz -O /boot/vmlinuz-xen6-install
wget http://mirror.centos.org/centos/6/os/i386/isolinux/initrd.img -O /boot/initrd-xen6-install
wget http://www.grantmcwilliams.com/files/xen-centos6-i386-install -O /etc/xen/centos6

3. Starting the installation

A kickstart file holds instructions for automatic installation and is referenced in my xen config above. My example kickstart file is very minimal but is enough to get a working CentOS 6 VM.

Note: I lost my original xen config files so I've created new ones here. I no longer have a xen system so I can't test them. Please let me know if the tutorial still works or not -Grant

Introduction

A lot of this tutorial was stolen from my CentOS 5 Installation which in turn was stolen from the CentOS wiki. I've shortened and updated it for installing a CentOS 6 DomU. I just copy and paste all the indented lines into a root terminal and voila! a CentOS VM.

1. Creating an Virtual Disk Image

The first step is to create an disk image that will act as the VM hard drive. The following command will create a 4 GB sparse disk image named /srv/xen/centos6.img. A sparse file is created in such a way that the disk image doesn't actually take up the whole 4GB until you fill it up. If you'd like a larger (11GB) disk image substitute seek=10240 into the following line. I make my VMs nice and small so I can move them around easier. Making a disk image larger or adding a second drive later is easier than making it smaller or taking a drive away.

dd if=/dev/zero of=/srv/xen/centos6.img oflag=direct bs=1M seek=3800 count=1

wget http://mirror.centos.org/centos/6/os/x86_64/isolinux/vmlinuz -O /boot/vmlinuz-xen6-install
wget http://mirror.centos.org/centos/6/os/x86_64/isolinux/initrd.img -O /boot/initrd-xen6-install
wget http://www.grantmcwilliams.com/files/xen-centos6-x86_64-install -O /etc/xen/centos6

3. Starting the installation

A kickstart file holds instructions for automatic installation and is referenced in my xen config above. My example kickstart file is very minimal but is enough to get a working CentOS 6 VM.

Citrix has an opening for a Xen Evangelist. From their blog:

"The Xen Open Source Evangelist will be an advocate for Xen.org projects (Xen, Xen Cloud Platform and Xen ARM) and be primarily engaged with open source Xen users, upstream and downstream projects of Xen as well as developers of Xen.org projects. In addition the Open Source Xen Evangelist will be responsible for representing Citrix and explaining their products and services in the appropriate venues."

It goes on to say that the person would demo and speak at key events around the world, communicate with the community, educate people on Xen and encourage the community to contribute to Xen.  Sounds like an interesting opportunity. For more information apply at the Citrix site. 

I've mentioned before that XCP/Xenserver's xe command is great for scripting but not always that great for interactive use. Because XCP relies so much on using UUID's for identification it's not very human friendly. Also the xe help is quite bad leading to our team that's working on writing documentation for xe. Even so xe makes a great scripting tool. 

To show the difference between xe's output and what I think it could be let me introduce my lstemplate.sh script available in the XCP Downloads Section of this website. The xe command has a tendency to show output on multiple lines which isn't very parsable and is sort of hard to read. I understand that it's easier to program though. I however, like as much info on one line as possible allowing me to send the output into awk/cut if I wish and also keeps formatting clean. 

Below is the output from xe template-list 

  ....

You can see the output doesn't wrap well and isn't that easy to read. My biggest irritation is trying to find the template for the OS I want to use. There are a lot of templates and I usually end up scrolling for quite some time to get the right one. My other choice is to pipe the output of xe template-list into grep -B1 to search for the name and print the line before the name-label which will show the UUID number. For instance xe template-list | grep -B1 'Red Hat'. As easy as that is I find myself scanning the output of xe template-list in order to know what to grep for which defeats the purpose of grepping. 

To solve this I wrote a small script called lstemplate.sh (list template). Below is the output. 

You can also pass a -v (verbose) flag to get the descriptions too. 

To convert a QEMU qcow format disk to VirtualBox vdi format you need to have Qemu installed. Qemu has tools to help convert disk formats.

grant@workstation:~$ qemu-img convert hda-qcow.img -O raw hda.img

grant@workstation:~$ VBoxManage convertdd hda.img hda.vdi
VirtualBox Command Line Management Interface Version 1.6.0
(C) 2005-2008 Sun Microsystems, Inc.
All rights reserved.

Converting VDI: from DD image file="hda.img" to file="hda.vdi"...
Creating fixed image with size 1024966656 bytes (978MB)...

This will convert a QEMU qcow format disk image to VirtualBox vdi format.