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This KB article shows you how to monitor a Nagios Log Server cluster using the Nagios Cross-Platform Agent (NCPA) and Nagios XI.
This KB article assumes that you have:
The Nagios Cross-Platform Agent (NCPA) now ships by default with Nagios Log Server. A specialized management page is also available, at Admin > Management > Monitor Backend (NCPA).
On the page you should see 3 sections:
1. At the top, a button labelled Open NCPA Interface. This will open the main web interface for the agent on the selected cluster instance.
2. A Tokens management form.
Setting the token with this form will allow you to apply the same token to every agent on the cluster with one click.
If you're using HTTPS, make sure that you've accepted the certificate in your browser, otherwise this will only work for the current machine.
3. A Processes section.
At the bottom, you will see a display that allows you to view and manage the NCPA processes for all members of the cluster.
You can switch the viewed instance by clicking the drop-down menu labelled Instance.
To monitor the NLS cluster, go to your Nagios XI Interface, and go to Configure > Configuration Wizards > NCPA.
Most of this configuration wizard should be self-explanatory. However, at the bottom of Step 2 you will see a Plugins section with two special plugins listed:
To select a plugin, click the list icon to the right of the second box.
If check_os_cluster_status.sh is selected, Plugin Arguments should be left blank.
This plugin simply checks the Opensearch cluster status, and alerts OK/WARNING/CRITICAL based on whether status is GREEN/YELLOW/RED. Since 1-instance clusters YELLOW at best, these will also output an OK status.
If check_os_jvm_heap.sh is selected, warning and critical thresholds should be specified in the usual way, and expressed as a percentage of the total desired elasticsearch JVM heap usage. For instance, you may choose arguments like:
-w 80 -c 90
When finished, click the Next button until configuration is applied. If you've done everything correctly, you should see the normal NCPA service status alongside the custom plugins:
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