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Redback - MQTT Temperature Plugin in Nagios

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Yuhan Bulathsinhalage
Date: 21/09/2024

Guide to Setting Up MQTT Temperature Plugin in Nagios

This guide will help you integrate and configure an MQTT temperature plugin in Nagios for real-time monitoring of IoT temperature sensors.

Step 1: Install Required Dependencies​

Before configuring the plugin, ensure that all dependencies are installed on your Nagios server. The MQTT plugin may require Python or other libraries. You can install these dependencies by running the following command:

sudo apt-get install python3 python3-pip
pip3 install paho-mqtt

Step 2: Configure commands.cfg​

You will need to define the command for the MQTT temperature plugin in the commands.cfg file.

  1. Open the commands.cfg file:

    sudo nano /usr/local/nagios/etc/objects/commands.cfg

  2. Add the following command definition to the file:

    define command {
       command_name check-mqtt_temperature
       command_line /usr/local/nagios/libexec/check-mqtt_temperature.py -H $ARG1$ -t $ARG2$
    }

    This defines the custom command that Nagios will use to check the temperature data from the MQTT broker. Save and exit the file.

Step 3: Configure localhost.cfg​

Next, configure the service in the localhost.cfg file to enable monitoring using the temperature plugin.

  1. Open the localhost.cfg file:

    sudo nano /usr/local/nagios/etc/objects/localhost.cfg

  2. Add the following service definition for the MQTT temperature plugin:

    define service {
       use                   generic-service
       host_name             localhost
       service_description   MQTT Temperature Check
       check_command         check-mqtt_temperature!10.137.0.149!iot/device/temperature
       check_interval        1
       retry_interval        1
       contacts              nagiosadmin
       notifications_enabled 1
       notification_options  w,u,c,r
       notification_interval 60
       notification_period   24x7
    }

    This service will run the MQTT temperature check every minute and notify the admin via email if abnormal conditions are detected.

Step 4: Configure Alerts and Notifications​

To ensure email notifications are sent when a temperature threshold is crossed, configure the email alerts in Nagios.

  1. Install the necessary mail utilities:

    sudo apt-get install mailutils

  2. Configure the contact group and contact information:

    Open the contacts.cfg file:

    sudo nano /usr/local/nagios/etc/objects/contacts.cfg

  3. Add the following contact information:

    define contact {
       contact_name            nagiosadmin
       alias                   Nagios Admin
       email                   youremail@email.com
    }

    define contactgroup {
       contactgroup_name       admins
       alias                   Nagios Administrators
       members                 nagiosadmin
    }

    This configuration defines the recipient for the notification emails.

Step 5: Test Notifications​

To verify that email notifications are functioning correctly, manually trigger an alert by simulating an abnormal condition, such as stopping the MQTT service or setting an unrealistic temperature value. Nagios will detect the condition and send an email to the configured address.

Check your email inbox to confirm that the alert was received. You should see a message similar to this:

Email notification

Figure 1: Test E-mail

Step 6: Restart Nagios​

After configuring all necessary files, restart the Nagios service to apply the changes.

sudo systemctl restart nagios

This completes the setup of the MQTT temperature monitoring plugin in Nagios. You can now monitor IoT device temperatures and receive alerts when abnormal conditions are detected.