[APM] docs: add service map information (#62671)

docs/apm/service-maps.asciidoc

@@ -0,0 +1,48 @@
+[[service-maps]]
+=== Service maps
+
+beta::[]
+
+A service map is a real-time diagram of the interactions occurring in your application’s architecture.
+It allows you to easily visualize data flow and high-level statistics, like average transaction duration,
+requests per minute, errors per minute, and metrics, allowing you to quickly assess the status of your services.
+
+Our beta offering creates two types of service maps:
+
+* Global: All services and connections are shown.
+* Service-specific: Selecting a specific service will highlight it's connections.
+
+[role="screenshot"]
+image::apm/images/service-maps.png[Example view of service maps in the APM app in Kibana]
+
+[float]
+[[visualize-your-architecture]]
+=== Visualize your architecture
+
+Select the **Service Map** tab to get started.
+By default, all services and connections are shown.
+Whether your onboarding a new engineer, or just trying to grasp the big picture,
+click around, zoom in and out, and begin to visualize how your services are connected.
+
+If there's a specific service that interests you, select that service to highlight its connections.
+Clicking **Focus map** will refocus the map on that specific service and lock the connection highlighting.
+From here, select **Service Details**, or click on the **Transaction** tab to jump to the Transaction overview.
+You can also use the tabs at the top of the page to easily jump to the **Errors** or **Metrics** overview.
+
+While it's not possible to query in service maps, it is possible to filter by environment.
+This can be useful if you have two or more services, in separate environments, but with the same name.
+Use the environment drop down to only see the data you're interested in, like `dev` or `production`.
+
+[role="screenshot"]
+image::apm/images/service-maps-java.png[Example view of service maps with Java highlighted in the APM app in Kibana]
+
+[float]
+[[service-maps-legend]]
+=== Legend
+
+Nodes appear on the map in one of two shapes:
+
+* **Circle**: Instrumented services. Interior icons are based on the language of the agent used.
+* **Diamond**: Databases, external, and messaging. Interior icons represent the generic type,
+with specific icons for known entities, like Elasticsearch.
+Type and subtype are based on `span.type`, and `span.subtype`.

docs/apm/using-the-apm-ui.asciidoc

@@ -31,6 +31,8 @@ include::transactions.asciidoc[]
 
 include::spans.asciidoc[]
 
+include::service-maps.asciidoc[]
+
 include::errors.asciidoc[]
 
 include::metrics.asciidoc[]