Traffic accounting through proc

Traffic Accounting through /proc/net/dev

Introduction

Traffic accounting in OpenVZ can be done through data collection against /proc/net/dev in the individual containers on a HN.

Prerequisites

• OpenVZ
• RRDTool
• GNU AWK

Script

First create a directory to store your RRD files:

# mkdir /var/lib/rrd/

Then install this script:

#!/bin/sh
# Script Name:  vz_direct_traffic_log
# Author:       "Brian Harrington, Alticon Inc" <bharrington@alticon.net>
# Website:      htty://www.alticon.net
# Editor:       "Denis Titov, ISP Okeanika" <denis@okeanika.net.ua>

# Time to do the data collection.
for veid in $(/usr/sbin/vzlist -o veid -H)
do      
        RRDFILE="/var/lib/rrd/$veid.rrd"
        if ! test -e $RRDFILE; then
                echo $RRDFILE does not exist, creating.

                # Place your preferred RRD Creation command here
                # or use this one, following command will create new RRD file with 300 sec step (for 5 min cron)
                /usr/bin/rrdtool create $RRDFILE --step 300 \
                        DS:IN:COUNTER:1000:0:U \
                        DS:OUT:COUNTER:1000:0:U \
                        RRA:AVERAGE:0.5:1:600000 \
                        RRA:AVERAGE:0.5:100:60000 \
                        RRA:AVERAGE:0.5:1000:6000
        fi
        # Parse out the inbound/outbound traffic and assign them to the corresponding variables     
        eval `/usr/sbin/vzctl exec $veid "grep venet0 /proc/net/dev"  |  \
                awk -F: '{print $2}' | awk '{printf"CTIN=%s\nCTOUT=%s\n", $1, $9}'`

        # Send the data to the corresponding RRD time with (N)now as the update time
        /usr/bin/rrdtool update $RRDFILE N:$CTIN:$CTOUT
done

the following script uses previously generated RRDs, you'll get nice PNG pictures and index.html file with them:

#!/bin/sh
# Script Name:  vz_direct_traffic_render
# Author:       "Denis Titov, ISP Okeanika" <denis@okeanika.net.ua>
# Website:      http://www.okeanika.net.ua

rrd_path=/var/lib/rrd
www_path=/var/www/html/traf

# Clear out the old index, otherwise you end up with a repeating index. This would also be a good place to put a header.
rm ${www_path}/index.html

cd $rrd_path
for RRD in *.rrd
do
        CTID=$(echo $RRD | sed 's/.rrd$//')

        # list of intervals, 1d = last day, 1w = last week and so on
        for INT in 1h 1d 1w 1m 1y
        do
                /usr/bin/rrdtool graph ${www_path}/${CTID}-${INT}.png \
                        --start now-$INT --end now \
                        -w 1000 -h 500 \
                        --title "CTID $CTID - Interval $INT" \
                        DEF:in=$RRD:IN:AVERAGE AREA:in#aea:'IN' LINE1:in#0e0 \
                        DEF:out=$RRD:OUT:AVERAGE AREA:out#eaa:'OUT' LINE1:out#e00
                echo "<p><img src=\"${CTID}-${INT}.png\"><br/><br/></p>" >> ${www_path}/index.html
        done
done

Setup

Add this to cron to run vz_direct_traffic_log every 5 minutes and vz_direct_traffic_render every 30 minutes:

# cat << EOF >> /etc/crontab
*/5 * * * * root /path/to/script/vz_direct_traffic_log
*/30 * * * * root /path/to/script/vz_direct_traffic_render
EOF

To check the output of this later run:

# rrdtool fetch /var/lib/rrd/<veid>.rrd AVERAGE -s -3600

See also

• Traffic accounting with iptables
• Monitoring bandwidth of containers