[Inventory] Create new Inventory docs (#4341)

* Create new Inventory page

* Create new Inventory page

* Add the new inventory to nav

* Integrate reviewer's feedback

* Fix formatting

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Colleen McGinnis <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Colleen McGinnis <[email protected]>

* Integrate reviewers feedback

* More edits

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

* Update docs/en/serverless/inventory.mdx

Co-authored-by: Mike Birnstiehl <[email protected]>

---------

Co-authored-by: Colleen McGinnis <[email protected]>
Co-authored-by: Mike Birnstiehl <[email protected]>

docs/en/serverless/inventory.mdx

@@ -0,0 +1,98 @@
+---
+slug: /serverless/observability/inventory
+title: Inventory
+description: Learn about the new Inventory experience that enables you to monitor all your entities from one single place.
+tags: [ 'serverless', 'observability', 'inventory' ]
+---
+
+import Roles from './partials/roles.mdx'
+
+<p><DocBadge template="technical preview" /></p>
+
+Inventory provides a single place to observe the status of your entire ecosystem of hosts, containers, and services at a glance, even just from logs. From there, you can monitor and understand the health of your entities, check what needs attention, and start your investigations. 
+
+<DocCallOut title="Note">
+   The new Inventory requires the Elastic Entity Model (EEM). To learn more, refer to <DocLink slug="/serverless/observability/elastic-entity-model" />.
+</DocCallOut>
+
+<DocImage url="./images/inventory-catalog.png" alt="Inventory catalog"/>
+
+Inventory is currently available for hosts, containers, and services, but it will scale to support all of your entities.
+
+The EEM currently supports the inventory experience (as identified by `host.name`, `service.name`, and `container.id`) located in data identified by the following index patterns:
+
+**Hosts**
+
+Where `host.name` is set in `metrics-*`, `logs-*`, `filebeat-*`, and `metricbeat-*`
+
+**Services**
+
+Where `service.name` is set in `filebeat*`, `logs-*`, `metrics-apm.service_transaction.1m*`, and `metrics-apm.service_summary.1m*`
+
+**Containers**
+
+Where `container.id` is set in `metrics-*`, `logs-*`, `filebeat-*`, and `metricbeat-*`
+
+Inventory allows you to:
+
+- Filter for your entities to provide a high-level view of what you have leveraging your own tags and labels
+- Drill down into any host, container, or service to help you understand performance
+- Debug resource bottlenecks with your service caused by their containers and the hosts they run on.
+- Easily discover all entities related to the host, container or service you are viewing by leveraging your tags and labels
+
+## Explore your entities
+
+1. In your ((observability)) project, go to **Inventory** to view all of your entities.
+
+    When you open the Inventory for the first time, you'll be asked to enable the EEM. Once enabled, the Inventory will be accessible to anyone with the appropriate privileges.
+
+    <DocCallOut title="Note">
+    The Inventory feature can be completely disabled using the `observability:entityCentricExperience` flag in **Stack Management**.    
+    </DocCallOut>
+
+
+1. In the search bar, search for your entities by name or type, for example `entity.type:service`.
+
+For each entity, you can click the entity name and get a detailed view. For example, for an entity of type `service`, you get the following details:
+
+- Overview
+- Transactions
+- Dependencies
+- Errors
+- Metrics
+- Infrastructure
+- Service Map
+- Logs
+- Alerts
+- Dashboards
+
+<DocImage url="./images/entity-detailed-view.png" alt="Entity detailed view"/>
+
+If you open an entity of type `host` or `container` that does not have infrastructure data, some of the visualizations will be blank and some features on the page will not be fully populated.
+
+## Add entities to the Inventory
+
+Entities are added to the Inventory through one of the following approaches: **Add data** or **Associate existing service logs**.
+
+### Add data
+To add entities, select **Add data** from the left-hand navigation and choose one of the following onboarding journeys:
+
+<DocDefTerm>- Auto-detect logs and metrics</DocDefTerm>
+<DocDefDescription>
+ Detects hosts (with metrics and logs)    
+</DocDefDescription>
+
+
+<DocDefTerm>- Kubernetes</DocDefTerm>
+<DocDefDescription>
+ Detects hosts, containers, and services    
+</DocDefDescription>
+
+<DocDefTerm>- Elastic APM / OpenTelemetry / Synthetic Monitor</DocDefTerm>
+<DocDefDescription>
+ Detects services    
+</DocDefDescription>    
+
+### Associate existing service logs
+
+To learn how, refer to <DocLink slug="/serverless/observability/add-logs-service-name" />.

docs/en/serverless/serverless-observability.docnav.json

@@ -91,6 +91,10 @@
         }
       ]
     },
+    {
+      "label": "Inventory",
+      "slug": "/serverless/observability/inventory"
+    },
     {
       "slug": "/serverless/observability/apm",
       "classic-sources": [ "enApmGuideApmOverview" ],