Nagios Conference 2012 - Robert Bolton - Custom SNMP OID Creation


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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:

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Nagios Conference 2012 - Robert Bolton - Custom SNMP OID Creation

  1. 1. Custom SNMP OID Creation for System Monitoring Robert V. Bolton
  2. 2. 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) 2012 2
  3. 3. What we’re going to cover today. Why Bother Creating Custom OIDs OID Tree Structure Python Module: snmp_passpersist Real World Example: IOStat Statistics 2012 3
  4. 4. 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. 2012 4
  5. 5. OID Tree Structure • SNMP uses a hierarchical tree structure 2012
  6. 6. 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 • . is the top of the private branch • Vendor OIDs • Our Custom OIDs 2012
  7. 7. 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 install, and you’re done. • Import: import snmp_passpersist as snmp 2012
  8. 8. Python Module: snmp_passpersist contiued #!/usr/bin/python -u import snmp_passpersist as snmp from commands import getoutput base_oid="." 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) 2012
  9. 9. Python Module: snmp_passpersist contiued Add to /etc/snmp/snmpd.conf pass_persist . /usr/local/bin/ Results SNMPv2-SMI::private.1234. = INTEGER: 1 SNMPv2-SMI::private.1234. = INTEGER: 2 SNMPv2-SMI::private.1234. = INTEGER: 3 SNMPv2-SMI::private.1234. = STRING: "/dev/mapper/winkler-root" SNMPv2-SMI::private.1234. = STRING: "/dev/sda1" SNMPv2-SMI::private.1234. = STRING: "tmpfs" SNMPv2-SMI::private.1234. = Gauge32: 355793 SNMPv2-SMI::private.1234. = Gauge32: 48 SNMPv2-SMI::private.1234. = Gauge32: 1 2012
  10. 10. 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 2012
  11. 11. 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 • 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. 2012
  12. 12. Thank you! Questions? Robert V.