Custom SNMP OID Creation for System Monitoring Robert

Custom SNMP OID Creation for System Monitoring Robert V. Bolton robert. bolton@utah. edu

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 (KE 7 ZEA) www. robertvbolton. com 2012 2

What we’re going to cover today. Why Bother Creating Custom OIDs OID Tree Structure Python Module: snmp_passpersist Real World Example: IOStatistics 2012 3

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

OID Tree Structure • SNMP uses a hierarchical tree structure 2012

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 2012

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 2012

Python Module: snmp_passpersist contiued #!/usr/bin/python -u import snmp_passpersist as snmp from commands import getoutput base_oid=". 1. 3. 6. 1. 4. 1234. 1. 3" def get_file_systems(): file_systems = getoutput("df -i. P | awk '{print $1}'"). split('n') file_systems. remove('Filesystem') return file_systems def get_inode_count(): inode_count = getoutput("df -i. P | 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. Pass. Persist(base_oid) pp. start(update, 60) 2012

Python Module: snmp_passpersist contiued Add to /etc/snmpd. conf pass_persist. 1. 3. 6. 1. 4. 1234. 1. 3 /usr/local/bin/inode. Count. py Results SNMPv 2 -SMI: : private. 1234. 1. 3. 1. 1 = INTEGER: 1 SNMPv 2 -SMI: : private. 1234. 1. 3. 1. 2 = INTEGER: 2 SNMPv 2 -SMI: : private. 1234. 1. 3 = INTEGER: 3 SNMPv 2 -SMI: : private. 1234. 1. 3. 2. 1 = STRING: "/dev/mapper/winkler-root" SNMPv 2 -SMI: : private. 1234. 1. 3. 2. 2 = STRING: "/dev/sda 1" SNMPv 2 -SMI: : private. 1234. 1. 3. 2. 3 = STRING: "tmpfs" SNMPv 2 -SMI: : private. 1234. 1. 3. 3. 1 = Gauge 32: 355793 SNMPv 2 -SMI: : private. 1234. 1. 3. 3. 2 = Gauge 32: 48 SNMPv 2 -SMI: : private. 1234. 1. 3. 3. 3 = Gauge 32: 1 2012

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

Real World Example: 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. 2012

Thank you! www. chpc. utah. edu Questions? Robert V. Bolton robert. bolton@utah. edu