OBS-393 Simplify user interface for ECS installation

cmd/internal/ecs/README.md

@@ -0,0 +1,76 @@
+### Amazon Elastic Container Service (ECS)
+
+### Introduction
+
+- The Postman Live Collection Agent (LCA) attaches as a sidecar to the specified service.
+- The Postman collection is populated with endpoints observed from the traffic arriving at your service.
+- Both EC2 and Fargate capacity providers are supported.
+
+### Prerequisites
+
+- AWS credentials stored at `~/.aws/credentials` 
+- Your AWS credentials **must have** these AWS permissions [Setup ECS Permissions](#setup-aws-ecs-permissions)
+- ECS service must have public internet access. For more information, see [Ensure Internet Access](#ensure-internet-access),
+
+### Usage
+
+```
+POSTMAN_API_KEY=<postman-api-key> postman-lc-agent ecs add \
+--collection <postman-collectionID> \
+--region <aws-region> \
+--cluster <full ARN of ECS cluster> \
+--service <full ARN of ECS service>
+```
+
+**NOTE**: Updating your service with the newly modified task definition might take time. Please check the AWS console for progress.
+
+#### Additional configuration
+
+- See the help menu for further configuration.
+
+```
+postman-lc-agent ecs --help
+```
+
+### Uninstall
+
+- Update your ECS service to the old revision of the task definition.
+
+### Set up AWS ECS permissions
+
+- Attach the following policy to your AWS profile.
+
+```
+{
+	"Version": "2012-10-17",
+	"Statement": [
+		{
+			"Effect": "Allow",
+			"Action": [
+				"ecs:UpdateService",
+				"ecs:RegisterTaskDefinition",
+				"ecs:DescribeServices",
+				"ecs:TagResource",
+				"ecs:DescribeTaskDefinition",
+				"ecs:DescribeClusters"
+			],
+			"Resource": "*"
+		}
+	]
+}
+```
+- **Instead** of the above policy, [AmazonECS_FullAccess](https://docs.aws.amazon.com/AmazonECS/latest/userguide/security-iam-awsmanpol.html#security-iam-awsmanpol-AmazonECS_FullAccess) can also be used to ensure easy authorization.
+
+### Ensure internet access
+
+#### Fargate tasks
+
+- When using a public subnet, you can assign a public IP address to the task ENI.
+- When using a private subnet, the subnet can have a NAT gateway attached.
+- AWS Docs: See [Task networking for tasks hosted on Fargate](https://docs.aws.amazon.com/AmazonECS/latest/userguide/fargate-task-networking.html).
+
+#### EC2 tasks
+
+- Tasks must be launched in private subnets with NAT gateway. 
+- For more information, see [Task networking for tasks that are hosted on Amazon EC2 instances](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/task-networking.html)
+