Using OpsWorks to Configure EC2 instances

• Consistency: Each time you call a recipe, it performs the same sequence of operations. For example, if your recipe creates a configuration file for an app server, it will create the same one for each instance.
• Automation: You can have OpsWorks automatically run your recipes to perform tasks on dozens or hundreds of instances with no more effort than for one.
• Security: Instead of allowing SSH access to your instances, which is hard to control, you specify who can run recipes, and the recipes specify what will be performed.
• Dynamic configuration: You can have recipes run in response to system events, allowing your environment to automatically respond to changes such as server scaling.

The pass-data.rb recipe

1. Select Add a Stack to create an OpsWorks stack.
2. Give it a name and select Advanced.
3. Set Use custom Chef Cookbooks to Yes.
4. Set Repository type to Git.
5. Set the Repository URL to your forked repository (e.g., https://github.com/amazonwebservices/opsworks-first-cookbook). 

{
  "my_app_data": {
    "app1": {
      "name": "database_name",
      "host": "www.amazon.com",
      "password": "123"
    }
}}

Add a Layer

1. Select Add a Layer
2. Choose the Node.js App Server layer and click Add Layer
3. Click the layer’s edit action and scroll to the Custom Chef recipes section. You will notice there are several headings—Setup, Configure, Deploy, Undeploy, and Shutdown—which correspond to OpsWorks lifecycle events. OpsWorks triggers these events at these key points in the instance’s lifecycle, which runs the associated recipes.
4. Enter sample::pass-data next to Deploy, click + to add it to the list and click the Save button at the bottom to save the updated configuration. OpsWorks will then run this recipe whenever you deploy your app to the instances in the Node.js App Server layer.

Add an Instance

{
  "name": "hello-world",
  "description": "hello world test app",
  "version": "0.0.1",
  "private": true,
  "dependencies": {
    "express": "3.4.4"
  }
}

var express = require('express');
var app = express();

app.get('/', function(req, res) {
    res.setHeader('Content-Type', 'text/plain');
    res.sendfile('/srv/www/app1/shared/config/app_data.yml');
});

app.use(express.static('public'));

app.listen(80);
console.log('Listening on port 80');

1. Open the AWS IAM console and select Roles.
2. Click on the aws-opsworks-ec2-role (which is the default role your instances use) and under Role Policies click Attach Role Policy.
3. Scroll through the list, select the Amazon SNS Full Access policy, and apply it to the role.

The bash.rb recipe

1. Go back to the Stack page and click the Run Command button.
2. Select execute recipes on the Command menu.
3. In the Recipes to execute box type sample::bash.
4. Click the Execute Recipes button.

Summary