Ganglia relies on a multicast-based listen or announce protocol to monitor the state of a cluster and uses a tree of point-to-point connections amongst promoted nodes to federate clusters and aggregate their state.
The main components of a Ganglia infrastructure are three:
Monitoring Daemon (
gmond
)Metadata Daemon (
gmetad
)PHP Web frontend
We start deploying all the three components on our OpenNebula frontend though they could be placed on a dedicated machine, whether physical or not.
gmond
is the service that should run on the hosts we wish to monitor. Its features are:
It collects monitoring data from the current host
It announces its presence on the local network
It may receive the state of other gmond nodes through unicast or multicast sytems.
It replies to requests for the XML description of the cluster state
The gmond daemon is packaged in Ubuntu or Debian in the package called Ganglia-monitor:
$ sudo apt-get...