Script to macro manage cluster of nodes (hypervisors) and the domains
(virtuals) on them.

Used as an extension to virsh, which it calls quite often.

All nodes must be able to make an ssh connection to all other nodes using 
public key (no passwords). Note that this includes being able to make an ssh
connection to itself as, at this time, it simply makes an ssh connection to
whatever node is defined over.

There are two subdirectories, conf/ and var/.

conf/ is NOT what you think; the app does not have a static configuration.
conf/ contains domain (virtual) configurations in an XML format. They are
acquired using virsh dumpxml.

var/ contains YAML representations of Perl hashes which contains information
about nodes, domains and the relationship between them.

===== NOT IMPLEMENTED YET =====
havirt can be installed on any node, or on a completely separate machine. If
installed on multiple nodes, it can be safely be run simultaneously on multiple
nodes as file locking is enabled on any code which writes to /var

=== Installation

There is no fancy installer. Simply grab the files via subversion.

svn co http://svn.dailydata.net/svn/havirt/stable /path/to/install
ln -s /path/to/install/havirt /usr/local/bin/havirt

Some Perl modules are needed. 
Exporter
Getopt::Long
version
YAML::Tiny
Data::Dumper

Most may be on your system already, but you can run the following command on
Debian based systems to add the ones not in the base install.

apt install -y libdata-dump-perl libyaml-tiny-perl

=== Setup

Ensure all nodes can talk to each other (including themselves) via public
key encryption (no password). If havirt is on a separate machine, it
must be able to talk to all nodes.

Each should be able to talk to the other. I generally create a
/root/.ssh/config which contains aliases for simplicity.

Once you are sure all of your nodes can talk to each other, run the following
command for each node.

havirt node add NAMEOFNODE

where NAMEOFNODE is accessible either via DNS or an ssh alias.

When all nodes are added, you can list them with

havirt node list -t tsv

which will dump a tab delimited text file to STDOUT.

Now it is time to populate all of the domains currently running

havirt node scan # scan all nodes for running domains
havirt domain update # get conf for all domains and store in conf/
havirt domain list # show all domains

Note: domain list will not show nodes which have no domains on them.