Hi Ben
That's done it, thanks for the assist. I must have been blind missing that
in the doco.
Luke
On Sunday, 24 September 2023 at 18:36:08 UTC+10 Ben Kochie wrote:
> "relabel_configs" are for target labels, which are applied before the
> scrape. You're looking for "metric_relabel_configs", which happen after the
> scrape.
>
> Base example from the snmp_exporter + relabel to match your example regexp.
>
> scrape_configs:
> - job_name: 'snmp'
> static_configs:
> - targets:
> - 192.168.1.2 # SNMP device.
> - switch.local # SNMP device.
> - tcp://192.168.1.3:1161 # SNMP device using TCP transport and
> custom port.
> metrics_path: /snmp
> params:
> auth: [public_v2]
> 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.
> metric_relabel_configs:
> - source_labels: [ifAlias]
> regex: ".*(Z[0-9]{5}A)"
> target_label: service_id
>
> This is a common/standard thing to do.
>
> On Sun, Sep 24, 2023 at 10:28 AM Luke O'Donnell <[email protected]>
> wrote:
>
>> Hi All,
>>
>> I'm new to the stack so apologies if this is a silly question.
>>
>> I'm intending to use Prometheus + SNMP-Exporter to collect stats from a
>> large number of network devices (switches, routers, etc) using if_mib.
>>
>> An issue i'm having difficulty with is extracting a subset of the
>> "ifAlias" label returned by SNMP-Exporter. These represent the
>> "description" of network interfaces on networking gear.
>>
>> A subset of network interfaces are used for Services, which have a
>> well-known regex pattern. Unfortunately there is some degree of
>> inconsistency in the exact format of Interface descriptions, so regex-like
>> matching is required to pick out just the ServiceID. For example sake:
>> Pattern: /Z[0-9]{5}A/
>> Example ifAlias values:
>> Z12345A
>> Svc Z12345A
>> Service Z12345A
>>
>> I'm trying to create a new label called "Service" that for all of the
>> above 3 examples would just contain "Z12345A".
>>
>> Example data from snmp-collector:
>>
>> ifHCInOctets{ifAlias="Svc
>> Z12345A",ifDescr="TenGigabitEthernet0/0/4.ServiceInstance.1111",ifIndex="9",ifName="Te0/0/4.SI.11111"}
>>
>> 408
>>
>> I'm intending to build various dashboards (grafana), alerting etc that
>> requires the matching of the ServiceID. It therefore seems to make sense to
>> me to store these as a new label whenever there is a match. It could be
>> done at query-time, however there are many use-cases for using this
>> (hypothetical) label so it'd reduce query complexity to just take the hit
>> on storage and store it as a label.
>>
>> I'm unsure of how to go about this. My interpretation of relabel_configs
>> is that it can't be used for relabeling labels from scraped data, rather
>> only labels provided at SD time.
>>
>> Is there an approach using either SNMP-Exporter config or Prometheus
>> config that can achieve this? Or do i need to solve it either with some
>> sort of custom intermediate service, or accept that there will be
>> additional complexity (and performance hit) at query-time?
>>
>> Thanks in advance,
>>
>> Luke
>>
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>>
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