REMON module is one of JENNIFER independent agents that collects and process non-standard data and send it to JENNIFER server. In general, a monitoring solution is comprised of various functions such as data collection, processing, transmission, storage, and viewing. The REMON module is a generalized framework for data collection, processing, and transmission.

Using the REMON module, you can execute an arbitrary script on the OS or an arbitrary SQL on the database, or can execute a Java application that implements a specific SQL. Using these methods, you can collect non-standard data and send it to JENNIFER server.

In this article, we will explain how to configure REMON and how to write sample scripts to monitor system resources.

REMON Configuration

The REMON module is located in $JENNIFER_HOME/remon directory of the JENNIFER installation package. The REMON directory structure is as follow:

 REMON Installation

• Edit env.sh files located in $REMON_HOME using a text editor and set JAVA_HOME and REMON_HOME variables according to your system settings.

REMON_HOME=/home/jennifer/remon
JAVA_HOME=/home/java

• Configure REMON agent. The agent configuration file (remon.conf) is located in in $REMON_HOME/conf directory. The following are the default settings for REMON agent.

Starting REMON

To start the REMON module, execute the remon.sh script located in $REMON_HOME.

cd /home/jennifer/remon
./remon.sh

Using REMON scripts

You can write various scripts to collect data and sent it to REMON module. All scripts must be placed in $REMON_HOME/script directory. The following 3 examples show how to use REMON to collect CPU Information, Check Network Status and Disk Status

Example1: System CPU

This script will use Linux top command to get CPU utilization

• Create a new script file, we will call it cpu.sh

cd /home/jennifer/remon/script
vi cpu.sh

• Our cpu.sh looks like the following

#!/bin/sh
##############################################
#  REMON Script Header
#$ script = CPU
#$ agent= R01
#$ interval = 5
#$ fieldtype =float
#$ fieldname =CPU
##############################################
cpu=`top -d 0.5 -b -n2 | grep "Cpu(s)"|tail -n 1 | awk '{print $2 + $4}'`
echo $cpu

• The REMON script attribute is described in a single line that begins with #$ (Example: #$ agent=R01). However, for windows bat files, REM must be added at the beginning (Example: REM #$ agent=R01)
• Save the file and give it execution authority

chmod a+x cpu.sh

• Start REMON console

cd /home/jennifer/remon
./console

• Load the script using the load command

load cpu.sh

• Start the script using the start command

start cpu.R01

• You can verify that the script has started without any errors using the ls command and check the MESSAGE column of the result.

• At this point, REMON is collecting data successfully. Next, we will add a user-defined chart to JENNIFER dashboard to view the collected data.
• Start JENNIFER server if it was not running and open JENNIFER client.
• Go to Dashboard => User Defined Dashboard menu item.
• Select User Defined Chart from the upper left panel. Then select Line from the middle panel.
• Drag the Line chart to the design area, resize it to a suitable size.
• Click the chart properties to open the chart settings and properties.

• Enter a title for the chart in the title field.
• Click The [Remon List(p)] button to bring up REMON scripts lists.
• Select the CPU script and then click the [Select] Button.
• Click the [Save] button. 

• You should see CPU data now in the Line chart
• Close the edit mode by clicking the magnifying class icon

Example 2: Network Status

This script will use the "netstat" command to check network status

• Create another script file, net.sh
• Add the following example script to the file

#!/bin/sh
 
##############################################
#  REMON Script Header
#$ script = NET
#$ agent= R01
#$ interval = 5
#$ fieldtype = int
#$ fieldname = est,tim,fin
##############################################
 
net=`netstat -an`
est=`echo $net | grep EST | wc -l`
tim=`echo $net | grep TIME | wc -l`
fin=`echo $net | grep FIN | wc -l`
echo $est,$tim,$fin

• Save the file.
• From REMON console load the script in a similar fashion to the cpu script.
• Make sure that the script is running without any error messages.
• Add a new custom define chart to show the Network status data

Example 3: Disk Space

This script will display total size of the disk, used amount and free amount of the disk in megabytes.

• Create another script file, disk.sh.
• Add the following example script to the file.

#!/bin/sh
 
##############################################
#  REMON Script Header
#$ script = Disk
#$ agent= R01
#$ interval = 5
#$ fieldtype = int
#$ fieldname =Size,Used,Avail
##############################################
sz=`df -hm | awk '{ for (i=1; i<=NF; i++) if ($i=="1M-blocks") { getline; print $i }}'`
us=`df -hm | awk '{ for (i=1; i<=NF; i++) if ($i=="Used") { getline; print $i }}'`
av=`df -hm | awk '{ for (i=1; i<=NF; i++) if ($i=="Available") { getline; print $i }}'`

• Save the file and load the script.
• Make sure that the script is running without any error messages.
• Add a new custom define chart to show the disk space usage.

Here is an example of the user-defined dashboard after we added the Network and Disk Space charts