Lucee Developer

I recently installed a cluster of Ubuntu VMs for a client's web application. Now it was time for logging and monitoring, but that turned out to be not so simple at all. I couldn't find a solid Linux script which would log CPU and memory usage, so decided to write it myself.

The script extracts data from the files /proc/meminfo and /proc/loadavg, and saves them in sysinfo.log as a tab-delimited text file. The columns are:

Date   MemTotal   MemFree   MemCached   CPU-usage (=last minute avg.)

MemTotal will always remain the same, but is usefull for calculating relative available memory. MemFree + MemCached == available memory; don't be misled by the column name "MemFree".

#!/bin/bash

FILE=/home/paulk/sysinfo.log
MEMDATA=`sudo cat /proc/meminfo | egrep "^(MemTotal|MemFree|Cached)" | sed 's/[^0-9]\+//g' | tr '\n' '\t'`
CPUDATA=`sudo cat /proc/loadavg | sed 's/ .\+//'`

if [ ! -f $FILE ]
then
        echo "Date      MemTotal        MemFree MemCached       CPU-usage" > $FILE
fi
echo "$(date)   $MEMDATA        $CPUDATA" >> $FILE

Steps to install/use:

1. 

   Save this script as 'logsysinfo.sh' (for example in your home directory)
   
   1. $ nano ./logsysinfo.sh
   2. paste the script, then do CTRL + X
2. chmod the file to 755
   1. $ chmod 755 ./logsysinfo.sh
3. test-run:
   1. $ sudo ./logsysinfo.sh
   2. tail ./sysinfo.log
4. If the output of the last command was 2 lines (1st=header, 2nd=numbers), then all is good.
5. Make sure the log is updated every 5 minutes:
   1. $ sudo crontab -e
   2. add the following line in the text editor which just opened, then close the editor:
      1. */5 * * * * /home/paulk/logsysinfo.sh
   3. Wait for max 5 minutes, then do $ tail ./sysinfo.log again
   4. If there is more output then before, all seems to be working :)

Personally, I now use this log file for input of a daily monitoring script: check min-max available memory (= MemFree + MemCached), cpu spikes, etc. I hope it helps you out as well!