Table of Contents
Tools from the Ganglia Monitor suite: this is a very short description of the ganglia tools. You will find more information on the web site. IGGI release include 3.0.3 version of Ganglia.
gmond: a simple daemon that runs on every node and sends monitored data. A part of the ganglia-monitor-core package.
gexec: Provides transparent forwarding of stdin, stdout, stderr, and signals to and from remote processes, provides local environment propagation, and is designed to be robust and scalable to systems with over 1000 nodes. Internally, gexec operates by building an n-ary tree of TCP sockets and threads between gexec daemons and propagating control information up and down the tree. By using hierarchical control, gexec distributes both the work and resource usage associated with massive amounts of parallelism across multiple nodes, thereby eliminating problems associated with single node resource limits (e.g., limits on the number of file descriptors on front-end nodes). It consists of a daemon, a client program, and a library which provides programmatic interface to the gexec system.
gstat: The Ganglia Status Client (gstat) connects with a Ganglia Monitoring Daemon (gmond) and outputs a load-balanced list of cluster hosts. gstat queries gmond to get the client list, which is why gmond must be running if you use gstat. Conversely, gstat is a nice tool to test your gmond configuration.
gmetric: The Ganglia Metric Client (gmetric) announces a metric value to all Ganglia Monitoring Daemons (gmond's) that are listening on the cluster multicast channel. It's a command line tool and is used in the ganglia scripts (for example, in the ganglia-monitor-script)
gmetad: Written in Perl, this daemon collects data from multiple Ganglia Monitoring Daemon (gmond) sources and saves all data to a Round-Robin database. gmetad also exports the state of one or more clusters in XML in exactly the same manner as individual gmonds do, allowing you to build a hierarchy of unicast data paths for unlimited scalability and convenience.
This allows you to monitor a meta cluster, and is very useful if you wish to monitor a large cluster.
By default, gmond and ganglia-monitor-script are installed on IGGI nodes.
You can tune your configuration file by editing /etc/gmond.conf, but gmond can run with the default configuration file.
If you wish to extend the monitoring capabilities, install the ganglia-monitor-script on the nodes:
urpmi ganglia-monitor-script You have to do some configuration ,and set in cron wich script you want to use (lm_sensors, disk_free...).
By default, ganglia-webfrontend is installed and configured. Now you can start the monitor:
/etc/init.d/httpd restart /etc/init.d/gmond restart /etc/init.d/ganglia-monitor-script restart
then you can edit /etc/gmetad.conf to add the IP addresses of nodes running gmetad or gmond. By default, a line is added with just the gmond server running on the server.
This file contains all the hosts gmetad will share its XML data with (XML data is the concatenation of all gmond sources). By default, any connections from 127.0.0.1 for data sharing is allowed.
data_source "my_cluster" 127.0.0.1 10.0.1.253:8649 data_source "my_cluster2" 192.168.200.21:8651
In this example, we've added the IP address of one of the nodes of 'my_cluster' that runs gmetad and of 'my_cluster2', which is running the the gmetad of a second cluster.
If you want to remotely query gmetad from another computer, for example if your web server running gmetad-webfrontend is on another computer. Edit /etc/gmetad_trusted_hosts and add a line with the IP addresses that are allowed to query the gmetad cluster.
WARNING: IF YOU LEAVE A BLANK LINE, GMETA WON'T START
And finally, you may use the monitoring interface by accessing http://127.0.0.1/ganglia/ or by replacing 127.0.0.1 with the actual server IP address.