XAPI toolstack on a Debian-based distribution - proposed

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This is part of Project Kronos. Follow these instructions to get XCP's Xapi toolstack (including xapi, the XenAPI server daemon) installed on an Ubuntu Oneiric or Debian Squeeze box, using the upstream Linux kernel. This will effectively allow you to turn an existing Ubuntu or Debian machine into an XCP host. Note that this is *very much* a work-in-progress. Some features will be broken, and there will be a bit of manual configuration required. We appreciate any testing you do for this project, but please don't consider this production ready yet! Please visit the Kronos Supported Features page for a list of XCP features that are known to work on Kronos. The debian packages can be compiled from source following the instructions linked from the Project Kronos page.

Note for Debian users

If you intend to use Debian, we recommend you to carefully read /usr/share/doc/xcp-xapi/README.Debian.gz, which has notes on how to use XCP/Kronos in Debian, and which is maintained to be up-to-date with latest development. The Debian maintainer will update it, but it's not their job to update this wiki (which I just did still... :) ).

What's the best environment?

The best environment is a clean installed modern system with significant amounts of RAM and several cores. However, this guide is written in the knowledge that not everyone will be in the lucky position of having such a box to play with. In fact, many of us will be installing it on a moderately-sized box with an existing (upgraded) version of Ubuntu or Debian running. One of the authors of this guide (MikeCamel) is in exactly that position, so you are not alone. Hopefully this guide will be relevant to you, and will provide working instructions. If you have a problem, let us know.

A note about kernels Kronos is really aimed at distributions (such as Ubuntu Precise Pangolin or Debian SID/Wheezy) which use the 3.2 kernel. There is a nasty bug in the 3.0 series (and probably before) which means that, between them, a couple of the components of Xen are going to reduce the size of Dom0 (and therefore your main operating environment) to something under 1 GiB, which may cause you significant problems. There are work-arounds, but this is a real issue if you're planning to run the XAPI toolstack on Oneiric, for instance. There is a work-around available.

Prepare your system

Action Debian SID / Wheezy Ubuntu Oneiric or Precise
Install OS Install Debian Squeeze.

Convert to Unstable:

  • Edit /etc/apt/sources.list and replace 'squeeze' with 'wheezy'
sed -i 's/squeeze/wheezy/g' /etc/apt/sources.list
apt-get update
apt-get dist-upgrade
Install Ubuntu Precise.

Kronos will work with either Ubuntu Precise Server or Desktop, with the default kernel. If you want to use local storage, you will have to reserve an unformatted partition on your hard disk for xapi. In a later step, you will use this partition to create a local storage repository.

Install any required firmware Install firmware (only if necessary - http://wiki.debian.org/Firmware)
Set up repositories This part isn't needed anymore in Debian, as XCP is now in SID. For Oneiric: add the following to /etc/apt/sources.list 
deb http://ppa.launchpad.net/ubuntu-xen-org/xcp-unstable/ubuntu oneiric main
deb-src http://ppa.launchpad.net/ubuntu-xen-org/xcp-unstable/ubuntu oneiric main

run this (with sudo): 

apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9273A937

or

For Precise: add the following to /etc/apt/sources.list 

deb http://ppa.launchpad.net/ubuntu-xen-org/xcp-unstable/ubuntu precise main
deb-src http://ppa.launchpad.net/ubuntu-xen-org/xcp-unstable/ubuntu precise main

run this (with sudo): 

apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 9273A937


or (for Oneiric or Precise) 

apt-get install python-software-properties
add-apt-repository ppa:ubuntu-xen-org/xcp-unstable

Work around Open vSwitch bug (Ubuntu Oneiric)

If you are installing onto a fresh Oneiric system, then you will hit https://bugs.launchpad.net/ubuntu/+source/openvswitch/+bug/894754. This is fixed in Precise. The following steps also resolve it on that setup: To work around this: 

apt-get update
apt-get install openvswitch-datapath-dkms

Workaround xcp-networkd missing file (Ubuntu)

Before installing xapi run the following commands to work around a missing file in the packages: 

mkdir /etc/xcp
echo "bridge" >> /etc/xcp/network.conf

This will be addressed properly in a future release

Note that this is already fixed in Debian SID / Wheezy, with xcp-networkd asking you (through the Debconf interface) which type of network configuration you wish to use.

Install xapi (Ubuntu)

This step installs XCP's xapi and all its dependencies, including the Xen hypervisor.

Note: XCP requires lspci, part of the pciutils package. If you are installing on top of a freshly debootstrap'd install, you may not have this available, 

 apt-get install pciutils

will resolve this, otherwise xcp-xapi will fail to start and give you a connection refused error. 


apt-get update
apt-get install xcp-xapi
apt-get install xcp-xe


Once you've installed these packages, you can just do an `apt-get update && apt-get upgrade` to keep up with the latest builds.

Workaround VM's not going to power-state: halted after shutdown (Ubuntu)

In Ubuntu (eg: not in Debian SID / Wheezy) the current version of the packages, there is a bug that will prevent a VM from going to a halted power-state when you shut them down. This is caused by the VIF's not being properly torn down after the shutdown. This will be addressed in a future release. You can address this issue by editing the file at /usr/lib/xcp/scripts/vif. Go to the very end of the file and find the block of code below (around line 258): 

remove)
    if [ "${TYPE}" = "vif" ] ;then
        call_hook_script $DOMID "${ACTION}"
                # Unclear whether this is necessary, since netback also does it:
        logger -t script-vif "${dev}: removing ${HOTPLUG_STATUS}"
        xenstore-rm "${HOTPLUG_STATUS}"

and change the case from remove) to remove|offline) so that it looks like this: 

remove|offline)
    if [ "${TYPE}" = "vif" ] ;then
        call_hook_script $DOMID "${ACTION}"
                # Unclear whether this is necessary, since netback also does it:
        logger -t script-vif "${dev}: removing ${HOTPLUG_STATUS}"
        xenstore-rm "${HOTPLUG_STATUS}"

Workaround XAPI conflicts with XEND (Debian and Ubuntu)

You will need to disable xend from starting in order to get xcp-xapi to start. This is done by modifying the file at /etc/init.d/xend. Many of the setup processes in this script still need to run, but xend itself should not start. This will be resolved in a future release. The command to resolve this is: 

sed -i -e 's/xend_start$/#xend_start/' -e 's/xend_stop$/#xend_stop/' /etc/init.d/xend
update-rc.d xendomains disable

Workaround qemu keymap location preventing vncterm from starting

In order for vncterm to start up with a Linux VM, it needs to load the qemu keymaps however they are located in a location other than where it looks, this can be resolved with the following commands 

mkdir /usr/share/qemu
ln -s /usr/share/qemu-linaro/keymaps /usr/share/qemu/keymaps

Post-install setup

Optional: Make xen the default grub entry.

sed -i 's/GRUB_DEFAULT=.\+/GRUB_DEFAULT="Xen 4.1-amd64"/' /etc/default/grub
update-grub

Note: given the default set up for Ubuntu's grub (in /etc/default/grub), you don't get to see the splashscreen with kernel boot options. If you do want to see the list of options, you may need to change some of the settings in this file.

Another way to do this, as advised by the Debian wiki and in the Debian release notes is: 

cd /etc/grub.d
mv 10_linux 25_linux
update-grub2

Setup the network/interfaces file

This is likely to be /etc/network/interfaces - ensure that you don't remove any existing settings. Note that if you are running a DHCP server on this machine, then you may need to change the xenbr0 interface to a static or manual IP address, as DHCP may not come up in time to provide an address otherwise. 

auto lo xenbr0

iface xenbr0 inet dhcp
        bridge_ports eth0

If you don't use dhcp, but a fixed IP, then you can do: 

auto lo
iface lo inet loopback

# The primary network interface
auto xenbr0
iface xenbr0 inet static
	bridge_ports eth0
	address 1.2.3.4
	netmask 255.255.255.0
	network 1.2.3.0
	broadcast 1.2.3.255
	gateway 1.2.3.1

Also, if you use the openvswitch mode (and not bridging), then you will need to tell XCP about your network configuration: 

PIF_UUID=`xe pif-list device=eth0 --minimal`
xe pif-reconfigure-ip uuid=$PIF_UUID mode=static IP=1.2.3.4 netmask=255.255.255.0 gateway=1.2.3.1

or for DHCP: 

PIF_UUID=`xe pif-list device=eth0 --minimal`
xe pif-reconfigure-ip uuid=$PIF_UUID mode=dhcp

This is very important, as otherwise, you might loose network connectivity. I believe (I didn't test) that if you don't have physical access to the server, the correct way to do this is to first use the bridging mode, then do the above pif-reconfigure-ip, then switch to openvswitch mode and reboot.

Setup the xensource-inventory file

Note: this assumes that the root partition is on /dev/sda1 - change if required. Note: this assumes that your management interface will be xenbr0 - change if required. Note: In order to increase compatibility with XenCenter/OpenStack etc you can add the line 'PRODUCT_VERSION=6.0.0' to the /etc/xcp/inventory file. Note: You normally don't need this in Debian SID (I'm not sure for Ubuntu) as everything will be setup automatically. The PRIMARY_DISK for example is not needed. The PRODUCT_VERSION thing above is however needed if you intend to use Openstack. 

control_domain=`uuidgen`
installation=`uuidgen`

cat > /etc/xcp/inventory << EOF
CURRENT_INTERFACES='xenbr0'
BUILD_NUMBER='0'
CONTROL_DOMAIN_UUID='${control_domain}' 
INSTALLATION_UUID='${installation}'
MANAGEMENT_INTERFACE='xenbr0'
PRIMARY_DISK='/dev/sda1'
EOF

Set the Xen toolstack

You will need to set a TOOLSTACK variable to get xcp-xapi to start, you can do that with the following: 

echo 'TOOLSTACK="xapi"' > /etc/default/xen

Also See

Debian

Ubuntu

Reboot

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