Adding Metrics and adding SNMP - How?

[Jan Kühnemund]

Hi y'all,

hope I'm doing this right, I've not yet used a mailing list 🙂

I would like to know:

1. My browse_metrics is empty, except if I poll using prometheus, but then it calls the metrics prometheus_0 prometheus_1 and so on. How can I add metrics, how are they defined? I seem to have misssed that in the fetting started guide
2. I tried activating snmp by adding the relevant params via argument ("-Dsnmp.ifname=yes -Dsnmp.version=3" and so on) but it has not had a noticable effect. Where should I be able to see the network interface names?

Kind Regards Jan

[Peter Phaal]

Did you follow the instructions in the Getting Started guide (https://sflow-rt.com/intro.php)?

Are you sure you have configured the switches to send sFlow packet samples and counters (https://sflow-rt.com/agents.php)?

Does it look like the data is being received? The sFlow-RT status page should report non-zero sFlow Bytes and sFlow Packets.

Have you checked to see that status of the agents using the REST API, http://sflow-rt:8008/agents/json

What do you see if you use the REST API, for example, http://sflow-rt:8008/metrics/json?

You might want to using the sflow-test application to further verify the sFlow agent configurations (https://blog.sflow.com/2015/11/sflow-test.html).

Enabling snmp.ifname should result in interface names appearing in the Prometheus metrics query, for example,

https://grafana.com/grafana/dashboards/11201-sflow-rt-network-interfaces/

[Jan Kuehnemund]

I installed sflow-rt as a docker container on kubernetes with the application preinstalled (sflow-rt/prometheus) and I can see packets arriving. I have 3 agents which input packets and am able to see flows if I ask for e.g. ipsource. What I cannot see however are predefined metrics.

The /metrics/json outputs:

{
 "prometheus_0": 31,
 "prometheus_2": 31,
 "prometheus_1": 31
}

While the /agents/json outputs:

{
 "10.x.0.238": {
  "sFlowDatagramsLost": 2,
...snip...
  "sFlowDatagramsDuplicates": 0,
  "sFlowCounterLostSamples": 0
 },
 "10.x.0.240": {
  "sFlowDatagramsLost": 43,
...snip...
  "sFlowCounterDuplicateSamples": 0,
  "lastSeen": 11,
  "sFlowDatagramsDuplicates": 0,
  "sFlowCounterLostSamples": 0
 }
}

The sflow code is on a huawei router, it is not something I can change, but I'm pretty sure it is solid.

I did install the sflow network interface dashboard on grafana, but given my /prometheus/metrics/ALL/ALL/txt endpoint is empty, I am not able to see any data

---

Von: sflo...@googlegroups.com <sflo...@googlegroups.com> im Auftrag von Peter Phaal <peter...@gmail.com>
Gesendet: Montag, 22. April 2024 18:24
An: sFlow-RT <sflo...@googlegroups.com>
Betreff: [sflow-rt] Re: Adding Metrics and adding SNMP - How?

 

--
You received this message because you are subscribed to a topic in the Google Groups "sFlow-RT" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/sflow-rt/_MO5BYmwuLM/unsubscribe.
To unsubscribe from this group and all its topics, send an email to sflow-rt+u...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/sflow-rt/c59a2aee-7729-4a62-b6d1-9490a58f18can%40googlegroups.com.

[Peter Phaal]

The pre-defined metrics are the result of sFlow counter polling. Have you defined a counter polling interval on the Huawei routers and enabled counter polling on the interfaces? The following configuration guide is very old, but maybe the commands haven't changes much:

https://blog.sflow.com/2012/08/configuring-huawei-switches.html

FYI The prometheus_0, ... metrics are the flows defined by the prometheus application. If you enable counter polling you should also see metrics like ifinoctets, ifoutoctets, etc.

[Jan Kühnemund]

Hi Peter,

thanks, I looked into it, but the router I am using only supports flow sampling, not counter sampling. https://support.huawei.com/enterprise/en/doc/EDOC1100279274/c520bf56/sflow-configuration#EN-US_CONCEPT_0172373310
Is there any other way I could possibly get the interface names using SNMP, and be it writing my own sflow-rt application?

If not I am looking into using the MAC Adresses instead, but that would be very hacky and ugly

[Peter Phaal]

Hi Jan,

You should raise a defect report with Huawei since counter polling is a required feature of an sFlow agent:

3. Sampling Mechanisms

   The sFlow Agent uses two forms of sampling: statistical packet-based
   sampling of switched or routed Packet Flows, and time-based sampling
   of counters.

See https://sflow.org/sflow_version_5.txt. You could give them a pointer to sFlow-Test so that they can validate their sFlow implementation:

https://blog.sflow.com/2015/11/sflow-test.html

sFlow-RT relies on the sFlow counters to discover device interfaces, interface speeds, etc. and to trigger SNMP requests to discover ifName information if it isn't already present in the port_name counter structure:

/* Port name */
/* opaque = counter_data; enterprise = 0; format = 1005 */
struct port_name {
  string<255> name;
}

As a work around, you could load a topology, https://sflow-rt.com/topology.php.  You would need to include the nodes structure which uses names the ports on each device. In your flow definitions, you can use ifname:inputifindex to add the ifname as a flow key, https://sflow-rt.com/define_flow.php

It shouldn't be too hard to programmatically extract the mapping if ifName to ifIndex using Huawei APIs or via SNMP in order to build the topology.json object.

Peter