[7.3] [DOCS] Add Uptime architecture diagram to Uptime doc (#44920)

docs/uptime-guide/overview.asciidoc

@@ -1,11 +1,53 @@
 [role="xpack"]
 [[uptime-overview]]
-== Overview
+== Elastic Uptime overview
 
-The Elastic Uptime solution built on the Elastic Stack.
-It allows you to monitor the availability and response time of software services and applications in real time.
+Elastic Uptime allows you to monitor the availability and response times of applications and services in real time and to detect problems before they affect users.
+
+Elastic Uptime can help you to understand uptime and response time characteristics for your services and applications.
+It can be deployed both inside and outside your organization's network, so you can analyze problems from multiple vantage points.
+
+Elastic Uptime uses these components: *Heartbeat*, *Elasticsearch* and *Kibana*.
+
+[float]
+=== Heartbeat
+
+{heartbeat-ref}/index.html[Heartbeat] is an open source data shipper that performs uptime monitoring.
+Elastic Uptime uses Heartbeat to collect monitoring data from your target applications and services, and ship it to Elasticsearch.
+
+[float]
+=== Elasticsearch
+
+{ref}/index.html[Elasticsearch] is a highly scalable, open source, search and analytics engine.
+Elasticsearch can store, search, and analyze large volumes of data in near real-time.
+Elastic Uptime uses Elasticsearch to store monitoring data from Heartbeat in Elasticsearch documents.
+
+[float]
+=== Kibana
+
+{kibana-ref}/index.html[Kibana] is an open source analytics and visualization platform designed to work with Elasticsearch.
+You can use Kibana to search, view, and interact with data stored in Elasticsearch.
+You can easily perform advanced data analysis and visualize your data in a variety of charts, tables, and maps.
+
+The {kibana-ref}/xpack-uptime.html[Elasticsearch Uptime app] in Kibana provides a dedicated user interface for viewing uptime data and identifying problem areas.
+
+[float]
+=== Example deployments
+// ++ I like the Infra/logging diagram which shows Infrastructure and Logging apps as separate components inside Kibana
+// ++ In diagram, should be Uptime app, not Uptime UI, possibly even Elastic Uptime? Also applies to Infra/logging/APM.
+// ++ Need more whitespace around components.
+
+image::images/uptime-simple-deployment.png[Uptime simple deployment]
+
+In this simple deployment, a single instance of Heartbeat is deployed at a single monitoring location to monitor a single service.
+The Heartbeat instance sends the monitoring data to Elasticsearch.
+Then you can use the Uptime app in Kibana to view the data from Heartbeat and determine the status of the service.
+
+image::images/uptime-multi-deployment.png[Uptime multiple server deployment]
+
+In this deployment, two instances of Heartbeat are deployed at two different monitoring locations.
+Both instances monitor the same service.
+The Heartbeat instances send the monitoring data to Elasticsearch.
+As before, you can use the Uptime app in Kibana to view the Heartbeat data and determine the status of the service.
+When a failure occurs, the multiple monitoring locations enable you to pinpoint the area in which the failure has occurred.
 
-Based on {heartbeat-ref}/index.html[Heartbeat], an open source uptime monitor, Elastic Uptime is transparent,
-flexible, and developer-friendly.
-It can be deployed both inside and outside your organization's network to understand service uptime and
-response time characteristics from multiple network vantage points.