Tag Archives: Ganglia

Cluster field testing

I posted a link to my Banana Pi cluster on Reddit see how the server would cope with the traffic. It wasn’t a huge amount of traffic – about 4000 page views over two days. At its busiest, the cluster handled about 480 hits an hour.

Ganglia showed that none of the CPUs in the cluster were busy. This is pretty much what I expected would happen, and I now feel confident that the cluster can easily handle much larger amounts of traffic. It was also good to see that the data from Ganglia showed useful information that reflected what was happening to each server.

Ganglia cluster information

Ganglia 24 hour view of web server and database server clusters

I’ve also been working the newest site on the Banana Pi cluster, Linux Web Servers. I’ve written some articles about installing WordPress on Apache. It’s been a while since I worked with WordPress, and it was nice to get back to it.

I’ve started writing some posts about Nginx, which I hope to publish soon.

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Using Ganglia to monitor three Banana Pi clusters

I’ve done some testing of the Ganglia monitoring tool on three small Banana Pi clusters.

three Banana Pi clusters monitored by Ganglia

Ganglia grid overview

I used a cluster of four database servers, another cluster of four nodes running GlusterFS, and a cluster of two master nodes.

The Ganglia meta demon has to be installed on the master node (the node where Ganglia stores data and the web front-end).  Some configuration changes need to be made in /etc/ganglia/gmetad.conf:

  • set the ‘gridname’ directive
  • add data_source lines for each cluster
  • add a list of IP addresses to the trustedhosts directive

The data_source directive specifies the name and host/port details of a cluster.  There is one data_source line for each cluster.

The Ganglia monitor needs to be installed on each node.  It’s configuration file (/etc/ganglia/gmond.conf) also needs to be edited:

  • edit the cluster name
  • change the port number that the monitor uses to communicate with the master node.

Ganglia uses different ports to distinguish between different clusters, so the ports in gmond.conf should be the same for every node in a cluster, and each cluster needs to use a different port.

You can read about the details here: http://banoffeepiserver.com/server-monitoring/ganglia/set-up-ganglia-on-multiple-clusters.html.