​​SkyWalking UI Fails to Display Custom Metrics from OpenTelemetry Collector​

[dannytest2709-droid]

I am using OpenTelemetry to collect metrics and report them to SkyWalking OAP. Based on the data in Elasticsearch, the metrics data is present. However, when I select custom metrics on the SkyWalking UI, nothing is displayed. ​​Is this feature not supported? Furthermore, is SkyWalking's support for OpenTelemetry as a collector not very comprehensive?​

[dannytest2709-droid]

[wu-sheng]

AFAIK, it's supported. Which dashboard are you setting this widget? I can see it's instance metrics. You need to be sure, service and instance names are correct.

[wu-sheng]

We don't care if you are using our agent or otel's. That was not my question.
You need to have the correct service and instance names in the drop box in the UI, then the expression could retrieve the result.
The query protocol has expression and metadata, please ref to this, and notice the entity.

https://github.com/apache/skywalking-query-protocol/blob/a4172e1c5ee296ac4c89d9e310d4bb7ae9303411/metrics-v3.graphqls#L124

[wu-sheng]

I think you should read this doc, https://skywalking.apache.org/docs/main/latest/en/concepts-and-designs/mal/#metric-level-function

And refer to some existing rules.

skywalking/oap-server/server-starter/src/main/resources/otel-rules/elasticsearch/elasticsearch-cluster.yaml

Line 32 in 79860ca

expSuffix: tag({tags -> tags.cluster = 'elasticsearch::' + tags.cluster}).service(['cluster'], Layer.ELASTICSEARCH)

[wu-sheng]

When you use OTEL collector or agent, the metadata is not generated automatically, because it is impossible.
You need to write your rules to pick correct tag and use scripts to build it.

[wu-sheng]

To test this, I then deployed a SkyWalking Agent to the same service. The service instance immediately appeared in the SkyWalking UI. However, ​​the metrics collected by the OpenTelemetry Collector were still not linked or associated with this now-existing service instance​​.

This test doesn't mean anything. Our agent works because we provided bundled rules in OAP backend. That is why in the document, we have marketplace to provide native dashboards, which are all well set. In your case, this part is on your own, although it is not hard, still you need to understand your data and build data connections.

[dannytest2709-droid]

ok