Install an SNMP Agent and Configure Telegraf SNMP Input
Video Lecture
Description
SNMP stands for Simple Network Management Protocol.
We can configure Telegraf to read SNMP, save it into InfluxDB and view it in Grafana.
Common devices that support SNMP are routers, switches, printers, servers, workstations and other devices found on IP networks.
Not every network device supports SNMP, or has it enabled, and there is a good chance you don't have an SNMP enabled device available that you can use in this lecture.
So, I will show you how to install SNMP on an Ubuntu 18 server.
I will use our Grafana server.
sudo apt install snmp snmpd snmp-mibs-downloader
Edit the snmpd.conf to set it's SNMP community. I set my community to mycommunity
sudo nano /etc/snmp/snmpd.conf
... rocommunity mycommunity default -V systemonly rocommunity6 mycommunity default -V systemonly ...
Restart
sudo service snmpd restart
Do a test query
snmpwalk -v 2c -c mycommunity 127.0.0.1 .
The response should show results with OID numbers like in this example output
iso.3.6.1.2.1.1.1.0 = STRING: "Linux grafana 4.15.0-72-generic #81-Ubuntu SMP Tue Nov 26 12:20:02 UTC 2019 x86_64" iso.3.6.1.2.1.1.2.0 = OID: iso.3.6.1.4.1.8072.3.2.10 iso.3.6.1.2.1.1.3.0 = Timeticks: (443) 0:00:04.43 iso.3.6.1.2.1.1.4.0 = STRING: "Me <me@example.org>" iso.3.6.1.2.1.1.5.0 = STRING: "grafana" iso.3.6.1.2.1.1.6.0 = STRING: "Sitting on the Dock of the Bay" iso.3.6.1.2.1.1.7.0 = INTEGER: 72 iso.3.6.1.2.1.1.8.0 = Timeticks: (11) 0:00:00.11 iso.3.6.1.2.1.1.9.1.2.1 = OID: iso.3.6.1.6.3.11.3.1.1 iso.3.6.1.2.1.1.9.1.2.2 = OID: iso.3.6.1.6.3.15.2.1.1 iso.3.6.1.2.1.1.9.1.2.3 = OID: iso.3.6.1.6.3.10.3.1.1 ... etc
Now to enable MIB descriptions instead of OIDs.
Edit the snmp.conf file
sudo nano /etc/snmp/snmp.conf
comment out the line mibs as below, using a #
#mibs
Save, and retry a query.
snmpwalk -v 2c -c mycommunity 127.0.0.1 .
It should now show the MIBs descriptions in the results like in this example output.
SNMPv2-MIB::sysDescr.0 = STRING: Linux grafana 4.15.0-72-generic #81-Ubuntu SMP Tue Nov 26 12:20:02 UTC 2019 x86_64 SNMPv2-MIB::sysObjectID.0 = OID: NET-SNMP-MIB::netSnmpAgentOIDs.10 DISMAN-EVENT-MIB::sysUpTimeInstance = Timeticks: (3015) 0:00:30.15 SNMPv2-MIB::sysContact.0 = STRING: Me <me@example.org> SNMPv2-MIB::sysName.0 = STRING: grafana SNMPv2-MIB::sysLocation.0 = STRING: Sitting on the Dock of the Bay SNMPv2-MIB::sysServices.0 = INTEGER: 72 SNMPv2-MIB::sysORLastChange.0 = Timeticks: (11) 0:00:00.11 SNMPv2-MIB::sysORID.1 = OID: SNMP-MPD-MIB::snmpMPDCompliance SNMPv2-MIB::sysORID.2 = OID: SNMP-USER-BASED-SM-MIB::usmMIBCompliance SNMPv2-MIB::sysORID.3 = OID: SNMP-FRAMEWORK-MIB::snmpFrameworkMIBCompliance ... etc
Now to configure Telegraf to read SNMP
sudo nano /etc/telegraf/telegraf.conf
Add this script below to the Inputs Plugins section
[[inputs.snmp]]
agents = [ "127.0.0.1:161" ]
version = 2
community = "mycommunity"
[[inputs.snmp.field]]
name = "hostname"
oid = "RFC1213-MIB::sysName.0"
is_tag = true
[[inputs.snmp.field]]
name = "uptime"
oid = "DISMAN-EXPRESSION-MIB::sysUpTimeInstance"
# IF-MIB::ifTable contains counters on input and output traffic as well as errors and discards.
[[inputs.snmp.table]]
name = "interface"
inherit_tags = [ "hostname" ]
oid = "IF-MIB::ifTable"
# Interface tag - used to identify interface in metrics database
[[inputs.snmp.table.field]]
name = "ifDescr"
oid = "IF-MIB::ifDescr"
is_tag = true
# IF-MIB::ifXTable contains newer High Capacity (HC) counters that do not overflow as fast for a few of the ifTable counters
[[inputs.snmp.table]]
name = "interface"
inherit_tags = [ "hostname" ]
oid = "IF-MIB::ifXTable"
# Interface tag - used to identify interface in metrics database
[[inputs.snmp.table.field]]
name = "ifDescr"
oid = "IF-MIB::ifDescr"
is_tag = true
# EtherLike-MIB::dot3StatsTable contains detailed ethernet-level information about what kind of errors have been logged on an interface (such as FCS error, frame too long, etc)
[[inputs.snmp.table]]
name = "interface"
inherit_tags = [ "hostname" ]
oid = "EtherLike-MIB::dot3StatsTable"
# Interface tag - used to identify interface in metrics database
[[inputs.snmp.table.field]]
name = "ifDescr"
oid = "IF-MIB::ifDescr"
is_tag = true
Save and restart Telegraf
sudo systemctl restart telegraf
⚠️ NOTE : By default SNMPD restricts how much information it returns. So currently we won't get any IF-MIB:: data from a SNMP query.
Go back into snmpd.conf and edit the view section to return more data.
sudo nano /etc/snmp/snmpd.conf
Change lines
... view systemonly included .1.3.6.1.2.1.1 view systemonly included .1.3.6.1.2.1.25.1 ...
to
... view systemonly included .1.3.6.1.2.1 #view systemonly included .1.3.6.1.2.1.25.1 ...
This will now return all data with the OID prefixes .1.3.6.1.2.1 which also includes interface information.