add docs on shield (#1665)

Author: HarshCasper

content/en/user-guide/aws/shield/index.md

@@ -0,0 +1,104 @@
+---
+title: "Shield"
+linkTitle: "Shield"
+description: Get started with Shield on LocalStack
+---
+
+## Introduction
+
+Shield is a managed Distributed Denial of Service (DDoS) protection service that safeguards applications running on AWS.
+Shield provides always-on detection and inline mitigations that minimize application downtime and latency, by protecting users from L4, L7 and most common L3, L4 network and transport layer DDoS attacks.
+Shield detection and mitigation is designed to protect against threats, including ones that are not known to the service at the time of detection.
+
+LocalStack allows you to use the Shield APIs in your local environment, and provides a simple way to mock and test the Shield service locally.
+The supported APIs are available on our [API coverage page](https://docs.localstack.cloud/references/coverage/coverage_shield/), which provides information on the extent of Shield's integration with LocalStack.
+
+## Getting Started
+
+This guide is designed for users new to Shield and assumes basic knowledge of the AWS CLI and our [`awslocal`](https://github.com/localstack/awscli-local) wrapper script.
+
+Start your LocalStack container using your preferred method.
+We will demonstrate how to create a Shield protection, list all protections, and delete a protection with the AWS CLI.
+
+### Create a Shield Protection
+
+To create a Shield protection, use the [`CreateProtection`](https://docs.aws.amazon.com/cli/latest/reference/shield/create-protection.html) API.
+The following command creates a Shield protection for a resource:
+
+{{< command >}}
+$ awslocal shield create-protection \
+  --name "my-protection" \
+  --resource-arn "arn:aws:elasticloadbalancing:us-east-1:000000000000:loadbalancer/app/my-alb/1234567890"
+{{< /command >}}
+
+The output should look similar to the following:
+
+```bash
+{
+    "ProtectionId": "67908d33-16c0-443d-820a-31c02c4d5976"
+}
+```
+
+### List all Protections
+
+To list all Shield protections, use the [`ListProtections`](https://docs.aws.amazon.com/cli/latest/reference/shield/list-protections.html) API.
+The following command lists all Shield protections:
+
+{{< command >}}
+$ awslocal shield list-protections
+{{< /command >}}
+
+The output should look similar to the following:
+
+```bash
+{
+    "Protections": [
+        {
+            "Id": "67908d33-16c0-443d-820a-31c02c4d5976",
+            "Name": "my-protection",
+            "ResourceArn": "arn:aws:elasticloadbalancing:us-east-1:000000000000:loadbalancer/app/my-alb/1234567890",
+            "ProtectionArn": "arn:aws:shield::000000000000:protection/67908d33-16c0-443d-820a-31c02c4d5976"
+        }
+    ]
+}
+```
+
+### Describe a Protection
+
+To describe a Shield protection, use the [`DescribeProtection`](https://docs.aws.amazon.com/cli/latest/reference/shield/describe-protection.html) API.
+The following command describes a Shield protection:
+
+{{< command >}}
+$ awslocal shield describe-protection \
+  --protection-id "67908d33-16c0-443d-820a-31c02c4d5976"
+{{< /command >}}
+
+Replace the protection ID with the ID of the protection you want to describe.
+The output should look similar to the following:
+
+```bash
+{
+    "Protection": {
+        "Id": "67908d33-16c0-443d-820a-31c02c4d5976",
+        "Name": "my-protection",
+        "ResourceArn": "arn:aws:elasticloadbalancing:us-east-1:000000000000:loadbalancer/app/my-alb/1234567890",
+        "ProtectionArn": "arn:aws:shield::000000000000:protection/67908d33-16c0-443d-820a-31c02c4d5976"
+    }
+}
+```
+
+### Delete a Protection
+
+To delete a Shield protection, use the [`DeleteProtection`](https://docs.aws.amazon.com/cli/latest/reference/shield/delete-protection.html) API.
+The following command deletes a Shield protection:
+
+{{< command >}}
+$ awslocal shield delete-protection \
+  --protection-id "67908d33-16c0-443d-820a-31c02c4d5976"
+{{< /command >}}
+
+## Current Limitations
+
+Shield Config is currently mocked in LocalStack.
+You can create, read, update, and delete Shield protections & subscriptions, but the actual protection or subscription is not applied to any resources.
+If you need this feature, please consider opening a [feature request on GitHub](https://github.com/localstack/localstack/issues/new).