[receiver/kubeletstats] Unit 1 must be used only for fractions and ratios

[walnuts1018]

Component(s)

receiver/kubeletstats

Describe the issue you're reporting

Describe

Some metrics, such as container.memory.page_faults, use 1 for Unit, but should be changed to use the appropriate Unit according to Metrics Semantic Conventions.

Metrics that need to be modified

• container.memory.major_page_faults
  • Change Unit from 1 to {page_fault}.
• container.memory.page_faults
  • Change Unit from 1 to {page_fault}.
• k8s.node.memory.major_page_faults
  • Change Unit from 1 to {page_fault}.
• k8s.node.memory.page_faults
  • Change Unit from 1 to {page_fault}.
• k8s.pod.memory.major_page_faults
  • Change Unit from 1 to {page_fault}.
• k8s.pod.memory.page_faults
  • Change Unit from 1 to {page_fault}.
• k8s.volume.inodes
  • Change Unit from 1 to {inode}.
• k8s.volume.inodes.free
  • Change Unit from 1 to {inode}.
• k8s.volume.inodes.used
  • Change Unit from 1 to {inode}.

Problems caused by using 1 for Unit

For example, when using the Prometheus Exporter, metrics in OpenTelemetry format are normalized to metric names according to conventions in Prometheus by looking at Unit, Metric Type, etc.

If a metric has a Metric Type of Gauge and a Unit of 1, the Prometheus Translator will assume that the metric represents a percentage of 0-1 and assign a Suffix of _ratio (https://github.com/open-telemetry/opentelemetry-collector-contrib/tree/main/pkg/translator/prometheus#:~:text=Percentages%20(unit%20is%201)), which is highly misleading. This is highly misleading.

[github-actions]

Pinging code owners:

• receiver/kubeletstats: @dmitryax @TylerHelmuth @ChrsMark

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[ChrsMark]

I guess open-telemetry/semantic-conventions#1032 should take care of that.