== Introduction ==
These scripts are used to build and manage Xen virtual machines on CentOS-based
Dom0 hypervisors.

These scripts were written very quickly to meet tight deadlines and ended up
pretty messy! They work, but will likely need a fair bit of work to run in a
different server environment.

== Virtual Machine/Guest Distros ==
The DomU guests can be various Linux distros, but each distro requires a
'script' creating in the virtual_machine.rb file to work. The distros that
work at this time (providing you have boot images for them) are as follows:

centos-5-i386
centos-5-x86_64
debian-4-i386
debian-4-amd64
debian-5-i386
debian-5-amd64
fedora-10-i386
fedora-10-x86_64
rhel-5-i386
rhel-5-x86_64
ubuntu-804-i386
ubuntu-804-amd64
ubuntu-810-amd64
ubuntu-904-i386
ubuntu-904-amd64

== The scripts ==
Most of these scripts talk about the virtual machine 'NAME' - this is the Xen
name as shown in the output of 'xm list'

vmcreate - create a virtual machine
vmcreateimage - create, format and mount an image (useful for manual guest
configurations)
vmdelete - delete a virtual machine
vmdistros - list the currently available distros, as set in the config file
vmlist - a cluster-aware 'xm list' clone
vmmount/vmumount - mount/unmount the disk of a vm to access it from Dom0 (will
exit if the virtual machine is running)
vmpackages - list the currently defined packages and their RAM & disk allocations
vmpasswordreset - reset the root password of a virtual machine (requires it to
be restarted)

== Things to know/assumptions about the environment ==
* The scripts create xen blktap file-based disks for the virtual machines and
allow you to specify whether to use SAN storage (assuming it's iSCSI and
available as a mount point) or local storage.
* The script needs to know if the hypervisor is part of a cluster, by listing
all cluster members in the config file. It will then copy out the xen config
for the guest over to each cluster member if it is set to use the SAN storage.
* The scripts assume you have access to a web server, hosting installation media
for the CentOS & RHEL distros.
* The CentOS & RHEL distros are set up using the kickstart method.
* The Debian and Ubuntu distros are set up using the debootstrap method.
* The scripts work on the basis of setting up a 'package' for the guests - the
packages define RAM and disk quotas
* The vmcreateimage script has some hard-coded assumptions about disk image
paths that were specific to our cluster environment to work around a sparse
image bug in CentOS 5.3 and Dell PowerEdge 1950 III SAS controllers.

== Config ==
Many of the settings for these scripts are set in a YAML config file, which
needs to be placed in /etc/vmscripts/vmconf.yml

== Installation ==
There's no installer available for these scripts, just clone the git repo, do
the following on each hypervisor in your cluster:
* Copy everything from the 'etc' directory into /etc/vmscripts/
* Copy everything from the 'lib' directory into /usr/lib/ruby/site_ruby/
* Copy everything from the 'bin' directory into /usr/local/sbin and make sure
each script is chmodded with executable permissions

== Usage ==
Each script has fairly comprehensive usage instructions - just run each one
with the --help switch.