Monitoring elasticsearch

elasticsearch is an open source distributed RESTful search engine built on top of Apache Lucene.
Like any service or component in your architecture, you’ll want to monitor it to ensure that it’s available and gather performance data to help with tuning.

In this brief post, we’ll look at how we can monitor elasticsearch using Opsview, which is built on Nagios and thus has access to a wide range of plugins, yet provides a more approachable user interface for configuring service checks.

Opsview configuration

The rest of the article assumes that you’ve got Opsview (or the Opsview VMWare appliance) installed & have completed the Quick Start.

elasticsearch-specific Plugin

We’ll install the plugin from https://github.com/rbramley/Opsview-elasticsearch into /usr/local/nagios/libexec/

The check_elasticsearch plugin is developed using Perl, so that it can be contributed back to Opsview. It requires the CPAN JSON module (sudo cpan -i JSON).

The plugin includes usage instructions, check_elasticsearch -h which can also be viewed in Opsview by selecting the ‘Show Plugin Help‘ link beneath the Plugin drop down.

Service check setup

Figure 1 gives an overview of service check configurations.

Figure 1 – Check definitions overview

The checks in action

The check results shown in Figure 2 are visible by navigating through the host group hierarchy.

Figure 2 – service check results

Note: They’re showing as warning because the checks were run against a standalone instance rather than a cluster.

Summary

The current checks are based on the Cluster Health API, the intention is to add stats/status checks too that will take threshold criteria and output performance data. The code for the check is on GitHub at https://github.com/rbramley/Opsview-elasticsearch so feel free to fork & send pull requests.