ganglia - distributed monitor system

Name
    ganglia - distributed monitoring system

Version
    ganglia 3.6.0

    The latest version of this software and document will always be found at
    http://ganglia.sourceforge.net/.

Synopsis
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                       /____/ Distributed Monitoring System

    Ganglia is a scalable distributed monitoring system for high-performance
    computing systems such as clusters and Grids. It is based on a
    hierarchical design targeted at federations of clusters. It relies on a
    multicast-based listen/announce protocol to monitor state within
    clusters and uses a tree of point-to-point connections amongst
    representative cluster nodes to federate clusters and aggregate their
    state. It leverages widely used technologies such as XML for data
    representation, XDR for compact, portable data transport, and RRDtool
    for data storage and visualization. It uses carefully engineered data
    structures and algorithms to achieve very low per-node overheads and
    high concurrency. The implementation is robust, has been ported to an
    extensive set of operating systems and processor architectures, and is
    currently in use on over 500 clusters around the world. It has been used
    to link clusters across university campuses and around the world and can
    scale to handle clusters with 2000 nodes.

    The ganglia system is comprised of two unique daemons, a PHP-based web
    frontend and a few other small utility programs.

    Ganglia Monitoring Daemon (gmond)
        Gmond is a multi-threaded daemon which runs on each cluster node you
        want to monitor. Installation is easy. You don't have to have a
        common NFS filesystem or a database backend, install special
        accounts, maintain configuration files or other annoying hassles.

        Gmond has four main responsibilities: monitor changes in host state,
        announce relevant changes, listen to the state of all other ganglia
        nodes via a unicast or multicast channel and answer requests for an
        XML description of the cluster state.

        Each gmond transmits in information in two different ways:
        unicasting/multicasting host state in external data representation
        (XDR) format using UDP messages or sending XML over a TCP
        connection.

    Ganglia Meta Daemon (gmetad)
        Federation in Ganglia is achieved using a tree of point-to-point
        connections amongst representative cluster nodes to aggregate the
        state of multiple clusters. At each node in the tree, a Ganglia Meta
        Daemon ("gmetad") periodically polls a collection of child data
        sources, parses the collected XML, saves all numeric, volatile
        metrics to round-robin databases and exports the aggregated XML over
        a TCP sockets to clients. Data sources may be either "gmond"
        daemons, representing specific clusters, or other "gmetad" daemons,
        representing sets of clusters. Data sources use source IP addresses
        for access control and can be specified using multiple IP addresses
        for failover. The latter capability is natural for aggregating data
        from clusters since each "gmond" daemon contains the entire state of
        its cluster.

    Ganglia PHP Web Frontend
        The Ganglia web frontend provides a view of the gathered information
        via real-time dynamic web pages. Most importantly, it displays
        Ganglia data in a meaningful way for system administrators and
        computer users. Although the web frontend to ganglia started as a
        simple HTML view of the XML tree, it has evolved into a system that
        keeps a colorful history of all collected data.

        The Ganglia web frontend caters to system administrators and users.
        For example, one can view the CPU utilization over the past hour,
        day, week, month, or year. The web frontend shows similar graphs for
        Memory usage, disk usage, network statistics, number of running
        processes, and all other Ganglia metrics.

        The web frontend depends on the existence of the "gmetad" which
        provides it with data from several Ganglia sources. Specifically,
        the web frontend will open the local port 8651 (by default) and
        expects to receive a Ganglia XML tree. The web pages themselves are
        highly dynamic; any change to the Ganglia data appears immediately
        on the site. This behavior leads to a very responsive site, but
        requires that the full XML tree be parsed on every page access.
        Therefore, the Ganglia web frontend should run on a fairly powerful,
        dedicated machine if it presents a large amount of data.

        The Ganglia web frontend is written in the PHP scripting language,
        and uses graphs generated by "gmetad" to display history
        information. It has been tested on many flavours of Unix (primarily
        Linux) with the Apache webserver and the PHP module (5.0.0 or
        later). The GD graphics library for PHP is used to generate pie
        charts in the frontend and needs to be installed separately. On
        RPM-based system, it is usually provided by the php-gd package.