packaging: add README to build Amazon Linux based ECS init RPM

Author: singholt

.gitignore

@@ -45,3 +45,4 @@ ecs-agent-*.tar
 *.DS_Store
 .run/
 pkg/
+.vscode/

packaging/amazon-linux-ami-integrated/README.md

@@ -0,0 +1,67 @@
+## Steps to build and install Amazon Linux ECS Init RPM:
+
+### Prerequisites
+
+* An **Amazon Linux instance** - This package is specifically designed for Amazon Linux distributions.
+* **Docker** - Docker must be installed and running. You can skip this step if you're using [ECS Optimized AMIs](https://docs.aws.amazon.com/AmazonECS/latest/developerguide/ecs-optimized_AMI.html), since they come with Docker pre-installed and running at startup. 
+  ```bash
+  # Query the available versions using "yum info docker", and install the latest available version.
+  # Example:
+  sudo yum install -y docker-25.0.8
+  ```
+
+* Install required build tools and dependencies:
+  ```bash
+  sudo yum install -y rpm-build make gcc git wget rpmdevtools
+  ```
+
+* Check out this amazon-ecs-agent package locally on your Amazon Linux instance.
+
+* **Go Language** - The build process requires Go:
+  ```bash
+  # Query the available versions using "yum info golang", and install the latest available version.
+  # Example:
+  sudo yum install -y golang-1.24.5
+  ```
+
+### Build
+
+1. **Build the Amazon Linux RPM**:
+   ```bash
+   make amazon-linux-rpm-codebuild
+   ```
+
+2. **Locate the built RPM**:
+   The RPM will be created in the current directory with the naming pattern:
+   - For x86_64: `ecs-init-{VERSION}-1.{amzn_version}.x86_64.rpm`
+   - For aarch64: `ecs-init-{VERSION}-1.{amzn_version}.aarch64.rpm` 
+
+### Install
+
+1. **Stop the existing ECS services** (if running):
+   ```bash
+   sudo systemctl stop ecs
+   sudo systemctl stop amazon-ecs-volume-plugin
+   ```
+
+2. **Remove existing ECS Init package** (if installed):
+   ```bash
+   sudo rpm -e ecs-init
+   ```
+
+3. **Install the ECS Init RPM built above**:
+   ```bash
+   sudo rpm -ivh ecs-init-{VERSION}-1.{amzn_version}.{architecture}.rpm
+   ```
+
+4. **(Optional) Install EFS Utils** if EFS support is needed:
+   
+   ECS AMIs come with EFS utils installed, so you can skip this step if you're using an ECS AMI.
+   
+   Otherwise, Follow instructions at: https://docs.aws.amazon.com/efs/latest/ug/installing-amazon-efs-utils.html#installing-other-distro for installation. 
+
+5. **Start and enable ECS services**:
+   ```bash
+   sudo systemctl enable --now ecs
+   sudo systemctl enable --now amazon-ecs-volume-plugin
+   ```