How to populate RRD database with CPU and MEM usage data? - shell

Question

I have a Lighttpd server (on Centos) and would like to display 4 graphs: lighttpd traffic, lighttpd requests per second, CPU usage and MEM usage. I've set place for rrd database for lighttpd config like this:
rrdtool.binary = "/usr/bin/rrdtool"
rrdtool.db-name = "/var/www/lighttpd.rrd"
And put into my WWW cgi-bin sh file that gets data from lighttpd RRD file and creates graphs of traffic and requests per second like this:
#!/bin/sh
RRDTOOL=/usr/bin/rrdtool
OUTDIR=//var/www/graphs
INFILE=/var/www/lighttpd.rrd
OUTPRE=lighttpd-traffic
WIDTH=400
HEIGHT=100
DISP="-v bytes --title TrafficWebserver \
DEF:binraw=$INFILE:InOctets:AVERAGE \
DEF:binmaxraw=$INFILE:InOctets:MAX \
DEF:binminraw=$INFILE:InOctets:MIN \
DEF:bout=$INFILE:OutOctets:AVERAGE \
DEF:boutmax=$INFILE:OutOctets:MAX \
DEF:boutmin=$INFILE:OutOctets:MIN \
CDEF:bin=binraw,-1,* \
CDEF:binmax=binmaxraw,-1,* \
CDEF:binmin=binminraw,-1,* \
CDEF:binminmax=binmaxraw,binminraw,- \
CDEF:boutminmax=boutmax,boutmin,- \
AREA:binmin#ffffff: \
STACK:binmax#f00000: \
LINE1:binmin#a0a0a0: \
LINE1:binmax#a0a0a0: \
LINE2:bin#efb71d:incoming \
GPRINT:bin:MIN:%.2lf \
GPRINT:bin:AVERAGE:%.2lf \
GPRINT:bin:MAX:%.2lf \
AREA:boutmin#ffffff: \
STACK:boutminmax#00f000: \
LINE1:boutmin#a0a0a0: \
LINE1:boutmax#a0a0a0: \
LINE2:bout#a0a735:outgoing \
GPRINT:bout:MIN:%.2lf \
GPRINT:bout:AVERAGE:%.2lf \
GPRINT:bout:MAX:%.2lf \
"
$RRDTOOL graph $OUTDIR/$OUTPRE-hour.png -a PNG --start -14400 $DISP -w $WIDTH -h $HEIGHT
$RRDTOOL graph $OUTDIR/$OUTPRE-day.png -a PNG --start -86400 $DISP -w $WIDTH -h $HEIGHT
$RRDTOOL graph $OUTDIR/$OUTPRE-month.png -a PNG --start -2592000 $DISP -w $WIDTH -h $HEIGHT
OUTPRE=lighttpd-requests
DISP="-v req --title RequestsperSecond -u 1 \
DEF:req=$INFILE:Requests:AVERAGE \
DEF:reqmax=$INFILE:Requests:MAX \
DEF:reqmin=$INFILE:Requests:MIN \
CDEF:reqminmax=reqmax,reqmin,- \
AREA:reqmin#ffffff: \
STACK:reqminmax#00f000: \
LINE1:reqmin#a0a0a0: \
LINE1:reqmax#a0a0a0: \
LINE2:req#00a735:requests"
$RRDTOOL graph $OUTDIR/$OUTPRE-hour.png -a PNG --start -14400 $DISP -w $WIDTH -h $HEIGHT
$RRDTOOL graph $OUTDIR/$OUTPRE-day.png -a PNG --start -86400 $DISP -w $WIDTH -h $HEIGHT
$RRDTOOL graph $OUTDIR/$OUTPRE-month.png -a PNG --start -2592000 $DISP -w $WIDTH -h $HEIGHT
Basically it's not my script, i get it from somewhere from the internet.
Now i would like to do the same for CPU usage and MEM usage.
I don't like to use any additional packages!
As you can see lighttpd populates lighttpd.rrd file with traffic data and requests per second. Now i would like to the system to populate second rrd file with CPU and MEM usage, so i can add to sh file code to generate graphs for this data.
How can I populate RRD file with CPU and MEM usage data?
Please, NO THIRD-PARTY tools !

Answer 1

the trick is to read data from files in the proc filesystem and use sed/awk to extract the actual value. Create an rrdfile with DS type GAUGE to store the data ... look at the tutorials on www.rrdtool.org to get going.