Added DLQ documentation (#30879)

* Added DLQ documentation

* some changes

* last edits

---------

Co-authored-by: cecilia saixue watt <[email protected]>

Author: ericfirth

config/_default/menus/main.en.yaml

@@ -4601,16 +4601,21 @@ menu:
       identifier: data_streams_live_messages
       parent: data_streams
       weight: 3
+    - name: Dead Letter Queues
+      url: data_streams/dead_letter_queues
+      identifier: data_streams_dead_letter_queues
+      parent: data_streams
+      weight: 4
     - name: Data Pipeline Lineage
       url: data_streams/data_pipeline_lineage
       identifier: data_streams_pipeline_lineage
       parent: data_streams
-      weight: 4
+      weight: 5
     - name: Metrics and Tags
       url: data_streams/metrics_and_tags
       identifier: data_streams_metrics_and_tags
       parent: data_streams
-      weight: 5
+      weight: 6
     - name: Data Jobs Monitoring
       url: data_jobs/
       pre: data-jobs-monitoring

content/en/data_streams/dead_letter_queues.md

@@ -0,0 +1,72 @@
+---
+title: Dead Letter Queues
+---
+
+Data Streams Monitoring (DSM) provides visibility into your non-empty dead letter queues (DLQs), enabling you to monitor and inspect message processing failures. DSM also enables you to remediate these message processing failures directly within Datadog.
+
+<div class="alert alert-info">Monitoring dead letter queues is available for Amazon SQS queues.</div>
+
+## Monitor DLQs
+
+### Setup
+* Enable [Data Streams Monitoring][1] for your messaging services.
+* Install the [Datadog-AWS integration][2]. Use this integration to manage permissions.
+* To remediate message processing failures within Datadog, additional setup is required. See the [Remediate DLQ issues](#remediate-dlq-issues) section.
+
+### Usage
+
+#### Create a monitor for a dead letter queue
+
+To track if your queue is rerouting messages to its DLQ, you can create a [metric monitors][8] that alerts on the [`data_streams.sqs.dead_letter_queue.messages`][8] metric.
+
+To create a monitor for a queue's DLQ:
+
+1. In Datadog, navigate to [Data Streams Monitoring][4].
+2. Select the **Explore** tab (default).
+3. Click on a supported queue to open its side panel.
+4. Select the **Dead Letter Queue** tab.
+5. Click **Create Monitor** to open a monitor setup page. The default inputs are sufficient to create a monitor that alerts when your DLQ is non-empty, but you can also make additional configurations on this page if you wish.
+6. Click **Create** at the bottom of the page.
+
+#### Detect message processing issues
+
+Data Streams Monitoring helps you detect where messages couldn't be processed and what downstream services could be affected:
+
+* The DSM [**Service Map**][6] highlights queues with messages in their DLQs, helping you to visually identify where failures occur
+
+* The DSM [**Issues**][7] page lists all queues that are experiencing message processing issues
+
+## Remediate DLQ issues
+You can inspect and resolve non-empty DLQs directly in Datadog by using [Datadog Actions][5].
+
+### Setup
+In Datadog, create a [Connection][9]. You need an IAM entity to perform the actions. This IAM entity can be an IAM User (with a secret access key) or IAM Role (assumed by using `sts:AssumeRole`) and have the following permissions:
+  * `sqs:ReceiveMessage` (for _peek_)
+  * `sqs:StartMessageMoveTask` (for _redrive_)
+  * `sqs:PurgeQueue` (for _purge_)
+
+These permissions can be applied globally to all SQS queues, or restricted to specific queues.
+
+### Usage
+
+After you set up the connection, you can click on a supported queue to open its side panel, where you can use the following actions:
+
+* **Peek** to inspect failed message content and identify the root cause
+* **Redrive** to requeue messages for another processing attempt
+* **Purge** to clear messages that no longer need processing
+
+## Troubleshooting
+If you are unable to see dead letter queue information:
+* Confirm that you have installed the [Datadog-AWS integration][2]
+* Confirm that your AWS role uses the AWS-managed `AmazonSQSReadOnlyAccess` policy
+* Confirm that your role has `sqs:ListQueues` and `sqs:GetQueueAttributes` permissions
+
+[1]: /data_streams/setup
+[2]: /integrations/amazon-web-services/
+[3]: /data_streams/metrics_and_tags/#data_streamssqsdead_letter_queuemessages
+[4]: https://app.datadoghq.com/data-streams/
+[5]: https://app.datadoghq.com/actions
+[6]: https://app.datadoghq.com/data-streams/map
+[7]: https://app.datadoghq.com/data-streams/issues
+[8]: /monitors/types/metric/
+[9]: https://app.datadoghq.com/actions/connections