Graphing

Some useful links to explain the concepts of Graphing

Concepts

Cacti

Metrics

Ganglia

What Ganglia does

  • Graph different properties of a server such as CPU,memory,load,etc

  • Compare the graphing trend of those properties with previous trend & identify which node or host is causing the issue easily from the trend.

  • Make custom metrics for graphing for different process.

  • Machines from different data centers which are part of one single cluster must be represented in that single cluster in a single interface.

Important points

  • Node : SINGLE machine sending data to Ganglia monitoring daemon. (All individual servers are nodes, can or can’t be part of a cluster)

  • Cluster : All nodes that are used for any particular purpose is a CLUSTER.

  • Grid : Collection of clusters is a GRID.

Parts of Ganglia Monitoring Tool

  • 1. Gmond :

    • Ganglia Monitoring daemon (Service that needs to be installed on each & every node that needs to be monitored)

    • Sends data via XML over TCP & main configuration file : /etc/gmond.conf

  • 2. Gmetad :

    • Collects data from Gmond daemons & stores in RRD (Round robin database)

    • Main configuration file is /etc/gmetad.conf & should be installed on one node of each cluster

  • 3. RRD tool :

    • Used by Ganglia to store data for visualization (graphing) & store data of particular time intervals & then graphs the same.

  • 4. PHP Front-End :

    • A web interface on the master node that displays graphs and metrics from data in the RRD tool.

Configuration

Troubleshooting & Log Parsing