OBSDOCS-1775: Cumulative-to-Delta Processor as a sidecar

TRACING-5164 | RHOSDT 3.6, OTEL deltatemporality metrics
Signed-off-by: Pavol Loffay <[email protected]>

Author: pavolloffay

observability/otel/otel-collector/otel-collector-processors.adoc

@@ -414,10 +414,12 @@ Optionally, you can create an `attribute_source` configuration, which defines wh
 [id="cumulativetodelta-processor_{context}"]
 == Cumulative-to-Delta Processor
 
-The Cumulative-to-Delta Processor processor converts monotonic, cumulative-sum, and histogram metrics to monotonic delta metrics.
+The Cumulative-to-Delta Processor converts monotonic, cumulative-sum, and histogram metrics to monotonic delta metrics.
 
 You can filter metrics by using the `include:` or `exclude:` fields and specifying the `strict` or `regexp` metric name matching.
 
+Because this processor calculates delta by storing the previous value of a metric, you must set up the metric source to send the metric data to a single stateful Collector instance rather than a deployment of multiple Collectors.
+
 This processor does not convert non-monotonic sums and exponential histograms.
 
 :FeatureName: The Cumulative-to-Delta Processor
@@ -427,24 +429,26 @@ include::snippets/technology-preview.adoc[]
 [source,yaml]
 ----
 # ...
-  config:
-    processors:
-      cumulativetodelta:
-        include: # <1>
-          match_type: strict # <2>
-          metrics: # <3>
-          - <metric_1_name>
-          - <metric_2_name>
-        exclude: # <4>
-          match_type: regexp
-          metrics:
-          - "<regular_expression_for_metric_names>"
-# ...
-----
-<1> Optional: Configures which metrics to include. When omitted, all metrics, except for those listed in the `exclude` field, are converted to delta metrics.
-<2> Defines a value provided in the `metrics` field as a `strict` exact match or `regexp` regular expression.
-<3> Lists the metric names, which are exact matches or matches for regular expressions, of the metrics to be converted to delta metrics. If a metric matches both the `include` and `exclude` filters, the `exclude` filter takes precedence.
-<4> Optional: Configures which metrics to exclude. When omitted, no metrics are excluded from conversion to delta metrics.
+mode: sidecar # <1>
+config:
+  processors:
+    cumulativetodelta:
+      include: # <2>
+        match_type: strict # <3>
+        metrics: # <4>
+        - <metric_1_name>
+        - <metric_2_name>
+      exclude: # <5>
+        match_type: regexp
+        metrics:
+        - "<regular_expression_for_metric_names>"
+# ...
+----
+<1> To tie the Collector's lifecycle to the metric source, you can run the Collector as a sidecar to the application that emits the cumulative temporality metrics.
+<2> Optional: You can limit which metrics the processor converts by explicitly defining which metrics you want converted in this stanza. If you omit this field, the processor converts all metrics, except the metrics that are listed in the `exclude` field.
+<3> Defines the value that you provided in the `metrics` field as an exact match by using the `strict` parameter or a regular expression by using the `regex` parameter.
+<4> Lists the names of the metrics that you want to convert. The processor converts exact matches or matches for regular expressions. If a metric matches both the `include` and `exclude` filters, the `exclude` filter takes precedence.
+<5> Optional: You can exclude certain metrics from conversion by explicitly defining them here.
 
 [id="groupbyattrsprocessor-processor_{context}"]
 == Group-by-Attributes Processor