Mismatch in count of OTel attributes to index and default label limit

[lindeskar]

Describe the bug
The count of OTel attributes to index (17) and the default label limit (15) do not match:

loki/docs/sources/shared/configuration.md

Lines 2008 to 2011 in 19fef93

	otlp_config:
	# List of default otlp resource attributes to be picked as index labels
	# CLI flag: -distributor.otlp.default_resource_attributes_as_index_labels
	[default_resource_attributes_as_index_labels: <list of strings> | default = [service.name service.namespace service.instance.id deployment.environment cloud.region cloud.availability_zone k8s.cluster.name k8s.namespace.name k8s.pod.name k8s.container.name container.name k8s.replicaset.name k8s.deployment.name k8s.statefulset.name k8s.daemonset.name k8s.cronjob.name k8s.job.name]]

loki/docs/sources/shared/configuration.md

Lines 2896 to 2898 in 19fef93

	# Maximum number of label names per series.
	# CLI flag: -validation.max-label-names-per-series
	[max_label_names_per_series: <int> | default = 15]

The 17 OTel resource attributes are also listed in the docs, which mentions the old default limit (max_label_names_per_series: 30):

loki/docs/sources/send-data/otel/_index.md

Lines 75 to 92 in 19fef93

	- Index labels: Resource attributes map well to index labels in Loki, since both usually identify the source of the logs. Because Loki has a limit of 30 index labels, we have selected the following resource attributes to be stored as index labels, while the remaining attributes are stored as [Structured Metadata]({{< relref "../../get-started/labels/structured-metadata" >}}) with each log entry:
	- cloud.availability_zone
	- cloud.region
	- container.name
	- deployment.environment
	- k8s.cluster.name
	- k8s.container.name
	- k8s.cronjob.name
	- k8s.daemonset.name
	- k8s.deployment.name
	- k8s.job.name
	- k8s.namespace.name
	- k8s.pod.name
	- k8s.replicaset.name
	- k8s.statefulset.name
	- service.instance.id
	- service.name
	- service.namespace

To Reproduce
Steps to reproduce the behavior:

1. Read the docs

Expected behavior
The count of attributes and labels match.

Environment:

• https://grafana.com/docs/loki/v3.0.x/configure/
• https://grafana.com/docs/loki/v3.0.x/send-data/otel/#format-considerations

Screenshots, Promtail config, or terminal output

Comment
I would have created a PR to fix the docs, but I suspect this might lead to a default config change?

[lindeskar]

Maybe the idea was that all attributes will never be used at once? (Deployment / StatefulSet / DaemonSet / ...)

If so, this issue is just reporting the old default limit (30) in:

loki/docs/sources/send-data/otel/_index.md

Line 75 in 19fef93

- Index labels: Resource attributes map well to index labels in Loki, since both usually identify the source of the logs. Because Loki has a limit of 30 index labels, we have selected the following resource attributes to be stored as index labels, while the remaining attributes are stored as [Structured Metadata]({{< relref "../../get-started/labels/structured-metadata" >}}) with each log entry:

[sandeepsukhani]

Maybe the idea was that all attributes will never be used at once? (Deployment / StatefulSet / DaemonSet / ...)

Yeah, not all attributes will be set at once. Some of them are mutually exclusive.

If so, this issue is just reporting the old default limit (30) in:

Yeah, it was a mistake. I think I referenced the old limit, which was 30 earlier. Thanks for pointing it out! I will fix it.