Updated otel readme (#4674) (#4681)

* updated otel readme

* Update internal/pkg/otel/README.md

Co-authored-by: Pierre HILBERT <pierre.hilbert@elastic.co>

* Update internal/pkg/otel/templates/README.md.tmpl

Co-authored-by: Pierre HILBERT <pierre.hilbert@elastic.co>

* Update internal/pkg/otel/templates/README.md.tmpl

Co-authored-by: Pierre HILBERT <pierre.hilbert@elastic.co>

* Update internal/pkg/otel/README.md

Co-authored-by: Pierre HILBERT <pierre.hilbert@elastic.co>

---------

Co-authored-by: Pierre HILBERT <pierre.hilbert@elastic.co>
(cherry picked from commit eaf3c43)

Co-authored-by: Michal Pristas <michal.pristas@gmail.com>

Author: mergify[bot]

internal/pkg/otel/README.md

@@ -8,15 +8,19 @@ To run the Elastic Distribution for OpenTelemetry Collector you can use Elastic-
 Running command 
 
 ```bash
-./elastic-agent -c otel.yml run
+./elastic-agent otel --config otel.yml
 ```
 
-from unpacked Elastic Agent package will run Elastic-Agent as an OpenTelemetry Collector. The `-c` flag needs to point to [OpenTelemetry Collector Configuration file](https://opentelemetry.io/docs/collector/configuration/) named `otel`, `otlp` or `otelcol`.
-Both `yaml` and `yml` suffixes are supported. 
+from unpacked Elastic Agent package will run Elastic-Agent as an OpenTelemetry Collector. The `--config` flag needs to point to [OpenTelemetry Collector Configuration file](https://opentelemetry.io/docs/collector/configuration/). OTel mode is available only using `otel` subcommand. Elastic Agent will not do any autodetection of configuration file passed when used without `otel` subcommand and will try to run normally.
 
-> In case this condition is not met, Elastic Agent will run in its default mode and will not behave as OpenTelemetry Collector.
 
-Note that `validate` subcommand and [feature gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md#controlling-gates) are not supported yet.
+To validate OTel configuration run `otel validate` subcommand:
+
+```bash
+./elastic-agent otel validate --config otel.yml
+```
+
+[feature gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md#controlling-gates) are supported using `--feature-gates` flag.
 
 ## Components
 

internal/pkg/otel/templates/README.md.tmpl

@@ -8,15 +8,19 @@ To run the Elastic Distribution for OpenTelemetry Collector you can use Elastic-
 Running command 
 
 ```bash
-./elastic-agent -c otel.yml run
+./elastic-agent otel --config otel.yml
 ```
 
-from unpacked Elastic Agent package will run Elastic-Agent as an OpenTelemetry Collector. The `-c` flag needs to point to [OpenTelemetry Collector Configuration file](https://opentelemetry.io/docs/collector/configuration/) named `otel`, `otlp` or `otelcol`.
-Both `yaml` and `yml` suffixes are supported. 
+from unpacked Elastic Agent package will run Elastic-Agent as an OpenTelemetry Collector. The `--config` flag needs to point to [OpenTelemetry Collector Configuration file](https://opentelemetry.io/docs/collector/configuration/). OTel mode is available only using `otel` subcommand. Elastic Agent will not do any autodetection of configuration file passed when used without `otel` subcommand and will try to run normally.
 
-> In case this condition is not met, Elastic Agent will run in its default mode and will not behave as OpenTelemetry Collector.
 
-Note that `validate` subcommand and [feature gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md#controlling-gates) are not supported yet.
+To validate OTel configuration run `otel validate` subcommand:
+
+```bash
+./elastic-agent otel validate --config otel.yml
+```
+
+[feature gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md#controlling-gates) are supported using `--feature-gates` flag.
 
 ## Components