Add target allocator guidance (#642)

* initial ta doc structure

* Add config example

* Add TA to add-on index

* fix prom casing

* Update TA description

* Update src/docs/getting-started/adot-eks-add-on/target-allocator.mdx

Author: bryan-aguilar

src/docs/getting-started/adot-eks-add-on.mdx

@@ -22,6 +22,7 @@ import operatorImg2 from "assets/img/docs/gettingStarted/operator/img2.png"
 #### [Advanced Collector Configuration for Amazon Managed Prometheus](/docs/getting-started/adot-eks-add-on/config-advanced)
 ### [Injecting Auto-instrumentation](/docs/getting-started/adot-eks-add-on/config-auto-instrumentation)
 ### [Kubernetes Attributes Processor](/docs/getting-started/adot-eks-add-on/k8s-attr-processor)
+### [Target Allocator](/docs/getting-started/adot-eks-add-on/target-allocator)
 ### [Update and Cleanup](/docs/getting-started/adot-eks-add-on/update-and-cleanup)
 
 

src/docs/getting-started/adot-eks-add-on/k8s-attr-processor.mdx

@@ -246,4 +246,4 @@ and alarms that can leverage Kubernetes resource attributes.
 
 ### [Advanced Collector Configuration for Amazon Managed Prometheus](/docs/getting-started/adot-eks-add-on/config-advanced)
 
-## [Next Topic: Updating and Cleanup](/docs/getting-started/adot-eks-add-on/update-and-cleanup)
+## [Next Topic: Target Allocator](/docs/getting-started/adot-eks-add-on/target-allocator)

src/docs/getting-started/adot-eks-add-on/target-allocator.mdx

@@ -0,0 +1,102 @@
+---
+title: 'Target Allocator'
+description:
+    This page provides an introduction to the Target Allocator
+path: '/docs/getting-started/adot-eks-add-on/target-allocator'
+---
+
+Installing the EKS Add-on gives you access to the Target Allocator (TA). Enabling the Target Allocator for an
+OpenTelemetry Collector custom resource decouples Prometheus service discovery and metrics collection. When enabled,
+the Target Allocator manages the configuration of the Prometheus receiver. Specifically,
+the Target Allocator allows for distribution of Prometheus scrape targets across a pool of Collectors. This functionality can
+be used to avoid the manual sharding of Prometheus scrape targets that can be required when horizontally scaling
+a single Prometheus receiver configuration.
+Visit the [Target Allocator Readme](https://github.com/open-telemetry/opentelemetry-operator/blob/main/cmd/otel-allocator/README.md)
+for a deeper introduction. 
+
+## Out of Order Samples
+
+In some cases the Target Allocator can be used to solve Prometheus remote write out of order sample errors. A common
+reason Collector users will see out of order sample erorrs is due to multiple collectors scraping the same metric
+endpoint. Collector users may experience this when horizontally scaling Collectors with Prometheus 
+receivers or daemonset deployments without manually sharding scrape targets. Both of these scenarios can lead to
+out of order sample erorrs without sharding of Prometheus scrape targets.
+
+## Getting Started
+
+Enabling the target allocator requires setting `OpenTelemeteryCollector.spec.targetAllocator.enabled` to `true`.
+This will cause the Prometheus configuration within the Collector CRD to be rewritten to use an `http_sd_config`
+from the Target Allocator. The operator will also create a new deployment and service for this http_sd_config
+directive.
+
+```
+apiVersion: opentelemetry.io/v1alpha1
+kind: OpenTelemetryCollector
+metadata:
+  name: collector-with-ta
+spec:
+  mode: statefulset
+  servicAccount: adot-collector
+  targetAllocator:
+    enabled: true
+  config: |
+    receivers:
+      prometheus:
+        config:
+          scrape_configs:
+          - job_name: 'otel-collector'
+            scrape_interval: 10s
+            static_configs:
+            - targets: [ '0.0.0.0:8888' ]
+            metric_relabel_configs:
+            - action: labeldrop
+              regex: (id|name)
+              replacement: $$1
+            - action: labelmap
+              regex: label_(.+)
+              replacement: $$1
+    
+    processors:
+      batch:
+
+    exporters:
+      prometheusremotewrite:
+        endpoint: ${AMP_REMOTE_WRITE_URL}
+        auth:
+          authenticator: sigv4auth
+    
+    extensions:
+      sigv4auth:
+        region: ${AWS_REGION}
+        service: "aps"
+
+
+    service:
+      pipelines:
+        metrics:
+          receivers: [prometheus]
+          processors: [batch]
+          exporters: [prometheusremotewrite]
+```
+
+Please reference the [OpenTelemetry Operator documentation](https://github.com/open-telemetry/opentelemetry-operator/tree/main#target-allocator) 
+for more information on using the Target Allocator. 
+
+### Useful links
+
+[Target Allocator API Spec](https://github.com/open-telemetry/opentelemetry-operator/blob/main/docs/api.md#opentelemetrycollectorspectargetallocator)
+
+[Scaling OpenTelmetery Collectors](https://opentelemetry.io/docs/collector/scaling/)
+
+--- 
+## [Previous Topic: Kubernetes Attributes Processor](/docs/getting-started/adot-eks-add-on/k8s-attr-processor)
+
+## Related Topics:
+
+### [Collector Configuration for Amazon Managed Prometheus](/docs/getting-started/adot-eks-add-on/config-amp)
+
+### [Collector Configuration for AWS CloudWatch](/docs/getting-started/adot-eks-add-on/config-cloudwatch)
+
+### [Advanced Collector Configuration for Amazon Managed Prometheus](/docs/getting-started/adot-eks-add-on/config-advanced)
+
+## [Next Topic: Updating and Cleanup](/docs/getting-started/adot-eks-add-on/update-and-cleanup)