nagios conference 2012 - robert bolton - custom snmp oid creation
DESCRIPTION
Robert Bolton presentation on creating custom SNMP OID's for use with Nagios. The presentation was given during the Nagios World Conference North America held Sept 25-28th, 2012 in Saint Paul, MN. For more information on the conference (including photos and videos), visit: http://go.nagios.com/nwcnaTRANSCRIPT
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About Robert V. Bolton
Systems Administrator
Center for High Performance Computing @ University of Utah
Mac Desktops, Linux Servers, HP Networking
Infrastructure Monitoring: Nagios and Cacti
Pyton Coder
Nagios Plugins and Cacti Scrtips
Student
Computer Engineering or Electrical Engineering
Expected Graduation = ?
Geek
Board Game Enthusiast
Amateur Radio Operator (KE7ZEA)
www.robertvbolton.com
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What we’re going to cover today.
Why Bother Creating Custom OIDs
OID Tree Structure
Python Module: snmp_passpersist
Real World Example: IOStat Statistics
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Why Bother Creating Custom OIDs
• SNMP is “simple” to use to gather system statistics.
• Nagios Plugins work great with Nagios, but may not provide data to other monitoring software.
• Example: NRPE Remote Execution.
• Offload Time Consuming System Checks.
• Provides Statistics for things not normally provided by in the SNMP tree.
OID Tree Structure
• SNMP uses a hierarchical tree structure
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OID Tree Structure Conitued
• Numbers are used to locate information
• Each number corresponds to a specific branch of the OID tree.
• Management Information Base (MIB) files map OID numbers to human readable format
• .1.3.6.1.4 is the top of the private branch
• Vendor OIDs
• Our Custom OIDs
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Python Module: snmp_passpersist
• Why Python…Because I know Python!
• I believe it is possible to create OIDs with Perl as well if your prefer.
• Github: nagius/snmp_passpersist
• Requires Net-SNMP
• Installation is easy: Download source, python setup.py install, and you’re done.
• Import: import snmp_passpersist as snmp
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Python Module: snmp_passpersist contiued
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#!/usr/bin/python -u
import snmp_passpersist as snmpfrom commands import getoutput
base_oid=".1.3.6.1.4.1234.1.3"
def get_file_systems(): file_systems = getoutput("df -iP | awk '{print $1}'").split('\n') file_systems.remove('Filesystem') return file_systems
def get_inode_count(): inode_count = getoutput("df -iP | awk '{print $3}'").split('\n') inode_count.remove('IUsed') return inode_count
def update():
file_systems = get_file_systems() inode_count = get_inode_count()
counter = 0 for x in file_systems: counter += 1 pp.add_int("1.%s" % str(counter),counter) pp.add_str("2.%s" % str(counter), x)
counter = 0 for x in inode_count: counter += 1 pp.add_gau("3.%s" % str(counter), x)
pp=snmp.PassPersist(base_oid)pp.start(update,60)
Python Module: snmp_passpersist contiued
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Add to /etc/snmp/snmpd.conf
pass_persist .1.3.6.1.4.1234.1.3 /usr/local/bin/inodeCount.py
Results
SNMPv2-SMI::private.1234.1.3.1.1 = INTEGER: 1SNMPv2-SMI::private.1234.1.3.1.2 = INTEGER: 2SNMPv2-SMI::private.1234.1.3.1.3 = INTEGER: 3SNMPv2-SMI::private.1234.1.3.2.1 = STRING: "/dev/mapper/winkler-root"SNMPv2-SMI::private.1234.1.3.2.2 = STRING: "/dev/sda1"SNMPv2-SMI::private.1234.1.3.2.3 = STRING: "tmpfs"SNMPv2-SMI::private.1234.1.3.3.1 = Gauge32: 355793SNMPv2-SMI::private.1234.1.3.3.2 = Gauge32: 48SNMPv2-SMI::private.1234.1.3.3.3 = Gauge32: 1
Real World Example: Iostat
• Problem
• User: “The network is slow!”
• Support: To many users hammering on a file system
• Solution Requirements
• Present Users with easy to read graphs of disk statistics.
• Allow for Nagios monitoring of disk statistics
• Minimal Impact of monitoring because of Iostat
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Real World Example: Iostat
• Iostat
• First output from Iostat is garbage.
• Cron Job runs Iostat and stores the results in a temp file
• Python Script iostat.py
• Reads results from temp file and uses snmp_passpersist to update a custom branch of OID tree.
• SNMP OID
• Data accessible to both Nagios and Cacti.
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