This exporter is the recommended way to expose SNMP data in a format which Prometheus can ingest.
To simply get started, it's recommended to use the if_mib module with
switches, access points, or routers.
While SNMP uses a hierarchical data structure and Prometheus uses an
n-dimnensional matrix, the two systems map perfectly, and without the need
to walk through data by hand. snmp_exporter maps the data for you.
Prometheus is able to map SNMP index instances to labels. For example, the ifEntry specifies an INDEX of ifIndex. This becomes the ifIndex label in Prometheus.
If an SNMP entry has multiple index values, each value is mapped to a separate Prometheus label.
SNMP is structured in OID trees, described by MIBs. OID subtrees have the same
order across different locations in the tree. The order under
1.3.6.1.2.1.2.2.1.1 (ifIndex) is the same as in 1.3.6.1.2.1.2.2.1.2
(ifDescr), 1.3.6.1.2.1.31.1.1.1.10 (ifHCOutOctets), etc. The numbers are
OIDs, the names in parentheses are the names from a MIB, in this case
IF-MIB.
Given a device with an interface at number 2, a partial snmpwalk return looks
like:
1.3.6.1.2.1.2.2.1.1.2 = INTEGER: 2 # ifIndex for '2' is literally just '2'
1.3.6.1.2.1.2.2.1.2.2 = STRING: "eth0" # ifDescr
1.3.6.1.2.1.31.1.1.1.1 = STRING: "eth0" # IfName
1.3.6.1.2.1.31.1.1.1.10.2 = INTEGER: 1000 # ifHCOutOctets, 1000 bytes
1.3.6.1.2.1.31.1.1.1.18.2 = STRING: "" # ifAlias
snmp_exporter combines all of this data into:
ifHCOutOctets{ifAlias="",ifDescr="eth0",ifIndex="2",ifName="eth0"} 1000
A single instance of snmp_exporter can be run for thousands of devices.
Binaries can be downloaded from the Github releases page and need no special installation.
We also provide a sample systemd unit file.
Start snmp_exporter as a daemon or from CLI:
./snmp_exporterVisit http://localhost:9116/snmp?module=if_mib&target=1.2.3.4 where 1.2.3.4 is the IP or
FQDN of the SNMP device to get metrics from and if_mib is the default module, defined
in snmp.yml.
The default configuration file name is snmp.yml and should not be edited
by hand. If you need to change it, see
Generating configuration.
The default snmp.yml covers a variety of common hardware walking them
using SNMP v2 GETBULK.
target and module can be passed as a parameter through relabelling.
Example config:
scrape_configs:
- job_name: 'snmp'
static_configs:
- targets:
- 192.168.1.2 # SNMP device.
- switch.local # SNMP device.
metrics_path: /snmp
params:
module: [if_mib]
relabel_configs:
- source_labels: [__address__]
target_label: __param_target
- source_labels: [__param_target]
target_label: instance
- target_label: __address__
replacement: 127.0.0.1:9116 # The SNMP exporter's real hostname:port.Similarly to blackbox_exporter,
snmp_exporter is meant to run on a few central machines and can be thought of
like a "Prometheus proxy".
The SNMP Exporter supports TLS and basic authentication. This enables better control of the various HTTP endpoints.
To use TLS and/or basic authentication, you need to pass a configuration file
using the --web.config.file parameter. The format of the file is described
in the exporter-toolkit repository.
Note that the TLS and basic authentication settings affect all HTTP endpoints: /metrics for scraping, /snmp for scraping SNMP devices, and the web UI.
Most use cases should be covered by our default configuration. If you need to generate your own configuration from MIBs, you can use the generator.
Use the generator if you need to customize which objects are walked or use non-public MIBs.
In order to provide accurate counters for large Counter64 values, the exporter will automatically wrap the value every 2^53 to avoid 64-bit float rounding. Prometheus handles this gracefully for you and you will not notice any negative effects.
If you need to disable this feature for non-Prometheus systems, use the
command line flag --no-snmp.wrap-large-counters.