commit ef1184369c04a038079cd6bcf2fd438cd776ac88
from: mischa <mischa@rx.high5.nl>
date: Thu Mar 14 15:37:45 2019 UTC
add blog post in README.html
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+<!DOCTYPE html>
+<html lang="en" class="black bg-white sans-serif lh-copy">
+<title>RRDtool looks nicer... - High5!</title>
+<meta charset="UTF-8">
+<body>
+<h1 id="RRDtool%20looks%20nicer...">RRDtool looks nicer...</h1>
+
+<p><a href="https://openbsd.amsterdam/">OpenBSD Amsterdam</a> was in search of a lightweight toolset to keep track of resource usage, at a minimum the CPU load generated by the <a href="https://man.openbsd.org/vmm.4">vmm(4)</a>/<a href="https://man.openbsd.org/vmd.8">vmd(8)</a> hosts and the traffic from and to the hosts. A couple of weeks ago we ended up with a workable [MRTG setup]. While it worked, it didn't look very pretty.</p>
+
+<p>In a moment of clarity, we thought about using <a href="https://oss.oetiker.ch/rrdtool/">RRDtool</a>. Heck, why shouldn't we give it a try? From the previous tooling, we already had some required building blocks in place to make <a href="https://oss.oetiker.ch/mrtg/">MRTG</a> understand the CPU Cores and uptime from <a href="https://openbsd.org/">OpenBSD</a>.</p>
+
+<p>We decided to split the collection of the different OIDs (SNMP Object Identifiers) into three different scripts, which <a href="https://man.openbsd.org/cron.1">cron(1)</a> calls, from a wrapper script.</p>
+
+<ul>
+<li>uptime.sh</li>
+<li>cpu_load.sh</li>
+<li>interface.sh</li>
+</ul>
+
+<h3 id="uptime.sh">uptime.sh</h3>
+
+<pre><code>#!/bin/sh
+test -n "$1" || exit 1
+HOST="$1"
+COMMUNITY="public"
+UPTIMEINFO="/tmp/${HOST}-uptime.txt"
+TICKS=$(snmpctl snmp get ${HOST} community ${COMMUNITY} oid hrSystemUptime.0 | cut -d= -f2)
+DAYS=$(echo "${TICKS}/8640000" | bc -l)
+HOURS=$(echo "0.${DAYS##*.} * 24" | bc -l)
+MINUTES=$(echo "0.${HOURS##*.} * 60" | bc -l)
+SECS=$(echo "0.${MINUTES##*.} * 60" | bc -l)
+test -n "$DAYS" && printf '%s days, ' "${DAYS%.*}" > ${UPTIMEINFO}
+printf '%02d\\:%02d\\:%02d\n' "${HOURS%.*}" "${MINUTES%.*}" "${SECS%.*}" >> ${UPTIMEINFO}
+</code></pre>
+
+<p>This is a seperate script, due to the uptime usage of both hosts in both graphs. </p>
+
+<p>The origins for this script can be found detailled in our <a href="https://chargen.one/obsdams/using-mrtg-again">MRTG Setup</a>.</p>
+
+<h3 id="cpu_load.sh">cpu_load.sh</h3>
+
+<pre><code>test -n "$1" || exit 1
+HOST="$1"
+COMMUNITY="public"
+RRDFILES="/var/rrdtool"
+IMAGES="/var/www/htdocs"
+WATERMARK="OpenBSD Amsterdam - https://obsda.ms"
+RRDTOOL="/usr/local/bin/rrdtool"
+CPUINFO="/tmp/${HOST}-cpu.txt"
+UPTIME=$(cat /tmp/${HOST}-uptime.txt)
+NOW=$(date "+%Y-%m-%d %H:%M:%S %Z" | sed 's/:/\\:/g')
+
+if ! test -f "${RRDFILES}/${HOST}-cpu.rrd"
+then
+echo "Creating ${RRDFILES}/${HOST}-cpu.rrd"
+${RRDTOOL} create ${RRDFILES}/${HOST}-cpu.rrd \
+ --step 300 \
+ DS:ds0:GAUGE:600:U:U \
+ RRA:MAX:0.5:1:20000
+fi
+
+snmpctl snmp walk ${HOST} community ${COMMUNITY} oid hrProcessorLoad | cut -d= -f2 > ${CPUINFO}
+CORES=$(grep -cv "^0$" ${CPUINFO})
+CPU_LOAD_SUM=$(awk '{sum += $1} END {print sum}' ${CPUINFO})
+CPU_LOAD=$(echo "scale=2; ${CPU_LOAD_SUM}/${CORES}" | bc -l)
+
+${RRDTOOL} update ${RRDFILES}/${HOST}-cpu.rrd N:${CPU_LOAD}
+
+${RRDTOOL} graph ${IMAGES}/${HOST}-cpu.png \
+ --start -43200 \
+ --title "${HOST} - CPU" \
+ --vertical-label "% CPU Used" \
+ --watermark "${WATERMARK}" \
+ DEF:CPU=${RRDFILES}/${HOST}-cpu.rrd:ds0:AVERAGE \
+ AREA:CPU#FFCC00 \
+ LINE2:CPU#CC0033:"CPU" \
+ GPRINT:CPU:MAX:"Max\:%2.2lf %s" \
+ GPRINT:CPU:AVERAGE:"Average\:%2.2lf %s" \
+ GPRINT:CPU:LAST:" Current\:%2.2lf %s\n" \
+ COMMENT:"\\n" \
+ COMMENT:" SUM CPU Load / Active Cores = % CPU Used\n" \
+ COMMENT:" Up for ${UPTIME} at ${NOW}"
+</code></pre>
+
+<p>On the first run, <a href="https://oss.oetiker.ch/rrdtool/">RRDtool</a> will create the .rrd file. On every subsequent run, it will update the file with the collected values and update the graph.</p>
+
+<p>The origins for this script can be found detailed in our <a href="https://chargen.one/obsdams/using-mrtg-again">MRTG Setup</a>.</p>
+
+<h3 id="interface.sh">interface.sh</h3>
+
+<pre><code>test -n "$1" || exit 1
+test -n "$2" || exit 1
+HOST="$1"
+INTERFACE="$2"
+COMMUNITY="public"
+RRDFILES="/var/rrdtool"
+IMAGES="/var/www/htdocs"
+WATERMARK="OpenBSD Amsterdam - https://obsda.ms"
+RRDTOOL="/usr/local/bin/rrdtool"
+UPTIME=$(cat /tmp/${HOST}-uptime.txt)
+NOW=$(date "+%Y-%m-%d %H:%M:%S %Z" | sed 's/:/\\:/g')
+
+if ! test -f "${RRDFILES}/${HOST}-${INTERFACE}.rrd"
+then
+echo "Creating ${RRDFILES}/${HOST}-${INTERFACE}.rrd"
+${RRDTOOL} create ${RRDFILES}/${HOST}-${INTERFACE}.rrd \
+ --step 300 \
+ DS:ds0:COUNTER:600:0:1250000000 \
+ DS:ds1:COUNTER:600:0:1250000000 \
+ RRA:AVERAGE:0.5:1:600 \
+ RRA:AVERAGE:0.5:6:700 \
+ RRA:AVERAGE:0.5:24:775 \
+ RRA:AVERAGE:0.5:288:797 \
+ RRA:MAX:0.5:1:600 \
+ RRA:MAX:0.5:6:700 \
+ RRA:MAX:0.5:24:775 \
+ RRA:MAX:0.5:288:797
+fi
+
+IN=$(snmpctl snmp get ${HOST} community ${COMMUNITY} oid ifInOctets.${INTERFACE} | cut -d= -f2)
+OUT=$(snmpctl snmp get ${HOST} community ${COMMUNITY} oid ifOutOctets.${INTERFACE} | cut -d= -f2)
+DESCR=$(snmpctl snmp get ${HOST} community ${COMMUNITY} oid ifDescr.${INTERFACE} | cut -d= -f2 | tr
+-d '"')
+
+${RRDTOOL} update ${RRDFILES}/${HOST}-${INTERFACE}.rrd N:${IN}:${OUT}
+
+${RRDTOOL} graph ${IMAGES}/${HOST}-${INTERFACE}.png \
+ --start -43200 \
+ --title "${HOST} - ${DESCR}" \
+ --vertical-label "Bits per Second" \
+ --watermark "${WATERMARK}" \
+ DEF:IN=${RRDFILES}/${HOST}-${INTERFACE}.rrd:ds0:AVERAGE \
+ DEF:OUT=${RRDFILES}/${HOST}-${INTERFACE}.rrd:ds1:AVERAGE \
+ CDEF:IN_CDEF="IN,8,*" \
+ CDEF:OUT_CDEF="OUT,8,*" \
+ AREA:IN_CDEF#00FF00:"In " \
+ GPRINT:IN_CDEF:MAX:"Max\:%5.2lf %s" \
+ GPRINT:IN_CDEF:AVERAGE:"Average\:%5.2lf %s" \
+ GPRINT:IN_CDEF:LAST:" Current\:%5.2lf %s\n" \
+ LINE2:OUT_CDEF#0000FF:"Out" \
+ GPRINT:OUT_CDEF:MAX:"Max\:%5.2lf %s" \
+ GPRINT:OUT_CDEF:AVERAGE:"Average\:%5.2lf %s" \
+ GPRINT:OUT_CDEF:LAST:" Current\:%5.2lf %s\n" \
+ COMMENT:"\\n" \
+ COMMENT:" Up for ${UPTIME} at ${NOW}"
+</code></pre>
+
+<p>To pinpoint the network interface you want to measure the bandwith for, this command prints the available interfaces:</p>
+
+<pre><code>snmpctl snmp walk community oid ifDescr
+</code></pre>
+
+<p>This will output a list like:</p>
+
+<pre><code>ifDescr.1="em0"
+ifDescr.2="em1"
+ifDescr.3="enc0"
+ifDescr.4="lo0"
+ifDescr.5="bridge880"
+ifDescr.6="vlan880"
+ifDescr.13="pflog0"
+ifDescr.669="tap0"
+ifDescr.670="tap1"
+</code></pre>
+
+<p>The number behind <code>ifDescr</code> is the one that you need to feed to <strong>interface.sh</strong>, for example:</p>
+
+<pre><code># interface.sh 5
+</code></pre>
+
+<p>Finally the <strong>wrapper.sh</strong> script calls all the aforementioned scripts:</p>
+
+<pre><code>#!/bin/sh
+SCRIPTS="/var/rrdtool"
+for i in $(jot 2 1); do ${SCRIPTS}/uptime.sh host${i}.domain.tld; done
+for i in $(jot 2 1); do ${SCRIPTS}/cpu_load.sh host${i}.domain.tld; done
+${SCRIPTS}/interface.sh host1.domain.tld 12
+${SCRIPTS}/interface.sh host2.domain.tld 11
+</code></pre>
+
+<p>The resulting graphs:</p>
+
+<p><img src="https://ops.high5.nl/obsda.ms/s1.obsda.ms-cpu.png" alt="" />
+<img src="https://ops.high5.nl/obsda.ms/s1.obsda.ms-12.png" alt="" /></p>
+
+<p>You can follow us on <a href="https://twitter.com/@OpenBSDAms">Twitter</a> and <a href="https://bsd.network/@OpenBSDAms">Mastodon</a>.</p>
+</body>
+</html>