Update infrastructure monitoring docs about containers (#4186)

* Update infrastructure monitoring docs about containers

* Apply changes from review

* Revert to 8.15 level info about container metrics

* Apply suggestions from code review

Fix containerd references.

---------

Co-authored-by: Colleen McGinnis <[email protected]>
(cherry picked from commit 38b0630)

docs/en/observability/monitor-infra/container-details-partial.asciidoc

@@ -0,0 +1,71 @@
+// This is collapsed by default
+[%collapsible]
+.*Overview*
+====
+
+The *Overview* tab displays key metrics about the selected container, such as CPU usage and memory usage.
+The metrics shown may vary depending on the type of container you're monitoring.
+
+Change the time range to view metrics over a specific period of time.
+
+Expand each section to view more detail related to the selected container, such as metadata,
+active alerts, and metrics.
+
+Hover over a specific time period on a chart to compare the various metrics at that given time.
+
+Click **Show all** to drill down into related data.
+
+[role="screenshot"]
+image::images/overview-overlay-containers.png[Container overview]
+====
+
+[%collapsible]
+.*Metadata*
+====
+
+The *Metadata* tab lists all the meta information relating to the container:
+
+* Host information
+* Cloud information
+* Agent information
+
+All of this information can help when investigating events—for example, filtering by operating system or architecture.
+
+[role="screenshot"]
+image::images/metadata-overlay-containers.png[Container metadata]
+====
+
+[%collapsible]
+.*Metrics*
+====
+
+The *Metrics* tab shows container metrics organized by type.
+
+[role="screenshot"]
+image::images/metrics-overlay-containers.png[Metrics]
+====
+
+[%collapsible]
+.*Logs*
+====
+
+The *Logs* tab displays logs relating to the container that you have selected. By default, the logs tab displays the following columns.
+
+|===
+
+| *Timestamp* | The timestamp of the log entry from the `timestamp` field.
+
+| *Message* | The message extracted from the document.
+The content of this field depends on the type of log message.
+If no special log message type is detected, the {ecs-ref}/ecs-base.html[Elastic Common Schema (ECS)]
+base field, `message`, is used.
+
+|===
+
+You can customize the logs view by adding a column for an arbitrary field you would like
+to filter by. For more information, refer to <<customize-stream-page,Customize Stream>>.
+To view the logs in the {logs-app} for a detailed analysis, click *Open in Logs*.
+
+[role="screenshot"]
+image::images/logs-overlay-containers.png[Container logs]
+====

docs/en/observability/monitor-infra/container-metrics.asciidoc

@@ -0,0 +1,84 @@
+[[container-metrics]]
+= Container metrics
+
+Learn about key container metrics displayed in the {infrastructure-app}:
+
+* <<key-metrics-docker,Docker>>
+* <<key-metrics-kubernetes,Kubernetes>>
+
+[discrete]
+[[key-metrics-docker]]
+== Docker container metrics
+
+These are the key metrics displayed for Docker containers.
+
+[discrete]
+[[key-metrics-docker-cpu]]
+=== CPU usage metrics
+
+[options="header"]
+|===
+| Metric                          | Description
+
+| **CPU Usage (%)**               | Average CPU for the container.
+
+**Field Calculation:** `average(docker.cpu.total.pct)`
+|===
+
+[discrete]
+[[key-metrics-docker-memory]]
+=== Memory metrics
+
+[options="header"]
+|===
+| Metric                           | Description
+
+|**Memory Usage (%)**              | Average memory usage for the container.
+
+**Field Calculation:** `average(docker.memory.usage.pct)`
+|===
+
+[discrete]
+[[key-metrics-docker-network]]
+=== Network metrics
+
+[options="header"]
+|===
+| Metric                            | Description
+
+| **Inbound Traffic (RX)**            | Derivative of the maximum of `docker.network.in.bytes` scaled to a 1 second rate.
+
+| **Outbound Traffic (TX)**           | Derivative of the maximum of `docker.network.out.bytes` scaled to a 1 second rate.
+|===
+
+[discrete]
+[[key-metrics-kubernetes]]
+== Kubernetes container metrics
+
+These are the key metrics displayed for Kubernetes (containerd) containers.
+
+[discrete]
+[[key-metrics-kubernetes-cpu]]
+=== CPU usage metrics
+
+[options="header"]
+|===
+| Metric                          | Description
+
+| **CPU Usage (%)**               | Average CPU for the container.
+
+**Field Calculation:** `average(kubernetes.container.cpu.usage.limit.pct)`
+|===
+
+[discrete]
+[[key-metrics-kubernetes-memory]]
+=== Memory metrics
+
+[options="header"]
+|===
+| Metric                           | Description
+
+|**Memory Usage (%)**              | Average memory usage for the container.
+
+**Field Calculation:** `average(kubernetes.container.memory.usage.limit.pct)`
+|===

docs/en/observability/monitor-infra/metrics-reference.asciidoc

@@ -5,14 +5,14 @@ Learn about the key metrics displayed in the Infrastructure app and how they
 are calculated.
 
 * <<host-metrics>>
+* <<container-metrics>>
 * <<kubernetes-pod-metrics>>
-* <<docker-container-metrics>>
 * <<aws-metrics>>
 
 include::host-metrics.asciidoc[leveloffset=+1]
 
-include::kubernetes-pod-metrics.asciidoc[leveloffset=+1]
+include::container-metrics.asciidoc[leveloffset=+1]
 
-include::docker-container-metrics.asciidoc[leveloffset=+1]
+include::kubernetes-pod-metrics.asciidoc[leveloffset=+1]
 
 include::aws-metrics.asciidoc[leveloffset=+1]

docs/en/observability/monitor-infra/view-infrastructure-metrics.asciidoc

@@ -35,10 +35,10 @@ Need help getting started? Follow the steps in
 To get started with your analysis, select the type of resources you want to show
 in the high-level view. From the *Show* menu, select one of the following:
 
-* *Hosts* (the default)
+* *Hosts* — the default
 * *Kubernetes Pods*
-* *Docker Containers*
-* *AWS*, which includes EC2 instances, S3 buckets, RDS databases, and SQS queues
+* *Docker Containers* — shows _all_ containers, not just Docker
+* *AWS* — includes EC2 instances, S3 buckets, RDS databases, and SQS queues
 
 When you hover over each resource in the waffle map, the metrics specific to
 that resource are displayed.
@@ -77,6 +77,36 @@ include::host-details-partial.asciidoc[]
 NOTE: These metrics are also available when viewing hosts on the **Hosts**
 page.
 
+[discrete]
+[[analyze-containers-inventory]]
+== View container metrics
+
+When you select **Docker containers**, the *Inventory* page displays a waffle map that shows the containers you
+are monitoring and the current CPU usage for each container.
+Alternatively, you can click the *Table view* icon image:images/table-view-icon.png[]
+to switch to a table view.
+
+Without leaving the *Inventory* page, you can view enhanced metrics relating to each container
+running in your infrastructure.
+
+****
+**Why do some containers report 0% or null (-) values in the waffle map?**
+
+The waffle map shows _all_ monitored containers, including containerd,
+provided that the data collected from the container has the `container.id` field.
+However, the waffle map currently only displays metrics for Docker fields.
+This display problem will be resolved in a future release.
+****
+
+On the waffle map, select a container to display the container details
+overlay.
+
+TIP: To expand the overlay and view more detail, click *Open as page* in the upper-right corner.
+
+The container details overlay contains the following tabs:
+
+include::container-details-partial.asciidoc[]
+
 [discrete]
 [[analyze-resource-metrics]]
 == View metrics for other resources

docs/en/observability/redirects.asciidoc

@@ -3,6 +3,11 @@
 
 The following pages have moved or been deleted.
 
+[role="exclude",id="docker-container-metrics"]
+=== Docker container metrics
+
+Refer to <<container-metrics>>.
+
 //Start links removed in Spacetime revamp (https://github.com/elastic/observability-docs/pull/2880)
 
 [role="exclude",id="spin-up-stack"]