Description

Discovered during elasticsearch issue investigation, several elasticsearch metrics were collected but not documented.

Added https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/13748
elasticsearch.cluster.in_flight_fetch
elasticsearch.cluster.pending_tasks

Added https://github.com/open-telemetry/opentelemetry-collector-contrib/issues/14027
elasticsearch.node.cache.count

Added https://github.com/open-telemetry/opentelemetry-collector-contrib/pull/13571
elasticsearch.node.fs.disk.free
elasticsearch.node.fs.disk.total

Always been there since initial receiver implementation
elasticsearch.node.operations.time

How has this been tested?

Metrics documentation generated from ./cmd/generate_expected_metrics script after using current version of ops-agent to monitor elasticsearch.

Checklist:

• Unit tests
  • Unit tests do not apply.
  • Unit tests have been added/modified and passed for this PR.
• Integration tests
  • Integration tests do not apply.
  • Integration tests have been added/modified and passed for this PR.
• Documentation
  • This PR introduces no user visible changes.
  • [] This PR introduces user visible changes and the corresponding documentation change has been made.
• Minor version bump
  • This PR introduces no new features.
  • This PR introduces new features, and there is a separate PR to bump the minor version since the last release already.
  • This PR bumps the version.