The Ambari Installation Wizard gives you the option of installing and configuring Nagios, including the provided Hadoop-specific alerts. The Nagios server, Nagios plugins, and its default web-based user interface are installed on the Nagios host, as specified during the installation procedure.
Some of the Nagios plugins also require the Simple Network Management Protocol (SNMP) daemon to work, so the daemon is automatically installed on all cluster nodes if Nagios is installed. For example, the SNMP daemon is used to collect information about system resources (like memory, storage, swap space, and CPU utilization).
![[Note]](../common/images/admon/note.png) | Note |
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By default the Nagios server does not use any authentication or encryption scheme while communicating with SNMP daemons. However you can enable secure communication with SNMP daemons by setting the appropriate SNMP configuration. |
