monitoring vm instances using ganglia

there was an excellent email (the author's name is matt massie) on the hadoop listserv on how to setup ganglia on an instance running within amazon.  the directions are not specific to amazon's aws, however, and is generalizable to any vm instance.  i've copied the email below.
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Ganglia doesn't need to be patched to work.  The patches are for Hadoop if
you are running ganglia 3.1.x (because of a breaking change in the ganglia
message format from 3.0.x to 3.1.x).

Since you are running fedora, you should be able to bring ganglia up by
using the ganglia RPMs which are available in the fedora repo.

Try the following commands on each node in the cluster you want to monitor

# yum install ganglia-gmond
# service gmond start

You will need to open TCP/UDP port 8649 as well to allow ganglia
communication (see your iptables configuration).  You can verify that gmond
is working by connecting to TCP port 8649

$ telnet localhost 8649

You should see an XML description of the state of the cluster/node.  Let me
know when you are this far in the installation and I'll help you through the
next steps.

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and some additional info from that same thread

Hadoop comes with a number of scripts to configure EC2 instances, see
"HADOOP_HOME/src/contrib/ec2/

bin"

If you take a look at "src/contrib/ec2/bin/image/hadoop-init" you will see
that it sets up Ganglia.