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AWS OpsWorks
User Guide (API Version 2013-02-18)

Step 2.5: Deploy an App

The IIS installation creates an C:\inetpub\wwwroot directory for your application's code and related files. The next step is to install an app in that directory. For this example, you will install a static HTML home page, default.html, in C:\inetpub\wwwroot. You can easily extend the general approach to handle more complex scenarios, such as ASP.NET applications.

You could include the application's files in your cookbook and have install.rb copy them to C:\inetpub\wwwroot. For examples of how to do this, see Example 6: Creating Files. However, this approach is not very flexible or efficient, and it is usually better to separate cookbook development from application development.

The preferred solution is to implement a separate deployment recipe that retrieves the application's code and related files from a repository—any repository you prefer, not just the cookbook repository—and installs it on each IIS server instance. This approach separates cookbook development from application development and, when you need to update your app, it allows you to just run the deployment recipe again without having to update your cookbooks.

This topic shows how to implement a simple deployment recipe that deploys default.htm to your IIS server. You can readily extend this example to more complex applications.

Create the Application and Store It in a Repository

You can use any repository you prefer for your applications. For simplicity, this example stores default.htm in a public S3 bucket.

To create the application

  1. Create a directory named iis-application in a convenient location on your workstation.

  2. Add a default.htm file to iis-application with the following content.

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    <!DOCTYPE html> <html> <head> <title>IIS Example</title> </head> <body> <h1>Hello World!</h1> </body> </html>
  3. Create an S3 bucket, upload default.htm to the bucket, and record the URL for later use. For simplicity, make the file public.

    Note

    This is a very simple application, but you can extend the basic principles to handle production-level applications.

    • For more complex applications with multiple files, it is usually simpler to create a .zip archive of iis-application and upload it to your S3 bucket.

      You can then download that file and extract the contents to the appropriate directory. There's no need to download multiple files, create a directory structure, and so on.

    • For a production application, you will probably want to keep your files private. For an example of how to have a recipe download files from a private S3 bucket, see Using the SDK for Ruby on an AWS OpsWorks Stacks Windows Instance.

    • You can store your application in any suitable repository.

      You typically download the application by using a repository's public API. This example uses the Amazon S3 API. If, for example, you store your application on GitHub, you can use the GitHub API.

Implement a Recipe to Deploy the Application

Add a recipe named deploy.rb to the iis-cookbook recipes directory, with the following contents.

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chef_gem "aws-sdk" do compile_time false action :install end ruby_block "download-object" do block do require 'aws-sdk' #1 Aws.config[:ssl_ca_bundle] = 'C:\ProgramData\Git\bin\curl-ca-bundle.crt' #2 query = Chef::Search::Query.new app = query.search(:aws_opsworks_app, "type:other").first s3region = app[0][:environment][:S3REGION] s3bucket = app[0][:environment][:BUCKET] s3filename = app[0][:environment][:FILENAME] #3 s3_client = Aws::S3::Client.new(region: s3region) s3_client.get_object(bucket: s3bucket, key: s3filename, response_target: 'C:\inetpub\wwwroot\default.htm') end action :run end

This example uses SDK for Ruby v2 to download the file. However, AWS OpsWorks Stacks does not install this SDK on Windows instances, so the recipe starts with chef_gem resource, which handles that task.

Note

The chef_gem resource installs gems into Chef's dedicated Ruby version, which is the version that recipes use. If you want to install a gem for a system-wide Ruby version, use the gem_package resource.

The bulk of the recipe is a ruby_block resource, which runs a block of Ruby code that uses the SDK for Ruby to download default.htm. The code in the ruby_block can be divided into the following sections, which correspond to the numbered comments in the code example.

1: Specify a Certificate Bundle

Amazon S3 uses SSL, so you need an appropriate certificate to download objects from an S3 bucket. SDK for Ruby v2 does not include a certificate bundle, so you must provide one and configure the SDK for Ruby to use it. AWS OpsWorks Stacks does not install a certificate bundle directly, but it does install Git, which includes a certificate bundle (curl-ca-bundle.crt). For convenience, this example configures the SDK for Ruby to use the Git certificate bundle for SSL. You also can install your own bundle and configure the SDK accordingly.

2: Retrieve the Repository Data

To download an object from Amazon S3, you need the AWS region, bucket name, and key name. As described later, this example provides this information by associating a set of environment variables with the app. When you deploy an app, AWS OpsWorks Stacks adds a set of attributes to the instance's node object. These attributes are essentially a hash table that contains the app configuration, including the environment variables. The app attributes for this application will look something like the following, in JSON format.

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{ "app_id": "8f71a9b5-de7f-451c-8505-3f35086e5bb3", "app_source": { "password": null, "revision": null, "ssh_key": null, "type": "other", "url": null, "user": null }, "attributes": { "auto_bundle_on_deploy": true, "aws_flow_ruby_settings": {}, "document_root": null, "rails_env": null }, "data_sources": [{"type": "None"}], "domains": ["iis_example_app"], "enable_ssl": false, "environment": { "S3REGION": "us-west-2", "BUCKET": "windows-example-app", "FILENAME": "default.htm" }, "name": "IIS-Example-App", "shortname": "iis_example_app", "ssl_configuration": { "certificate": null, "private_key": null, "chain": null }, "type": "other", "deploy": true }

The app's environment variables are stored in the [:environment] attribute. To retrieve them, you use a Chef search query to retrieve the app's hash table, which are all under the aws_opsworks_app node. This app will be defined as the other type, so the query searches for apps of that type. The recipe takes advantage of the fact that there is only one app on this instance, so the hash table of interest is just app[0]. For convenience, the recipe then assigns the region, bucket, and file names to variables.

For more information about how to use Chef search, see .Obtaining Attribute Values with Chef Search

3: Download the file

The third part of the recipe creates an S3 client object and uses its get_object method to download default.htm to the instance's C:\inetpub\wwwroot directory.

Note

A recipe is a Ruby application, so Ruby code doesn't necessarily have to be in a ruby_block. However, the code in the body of the recipe runs first, followed by the resources, in order. For this example, if you put the download code in the recipe body, it would fail because the chef_gem resource wouldn't have installed the SDK for Ruby yet. The code in the ruby_block resource executes when the resource executes, after the chef_gem resource has installed the SDK for Ruby.

Update the Instance's Cookbooks

AWS OpsWorks Stacks automatically installs custom cookbooks on new instances. However, you are working with an existing instance, so you must update your cookbook manually.

To update the instance's cookbooks

  1. Create a .zip archive of iis-cookbook and upload it to the S3 bucket.

    This will overwrite the old cookbook, but the URL will stay the same, so you don't need to update the stack configuration.

  2. If your instance is not online, restart it.

  3. After the instance is online, choose Stack in the navigation pane, and then choose Run Command.

  4. For Command, choose Update Custom Cookbooks. This command will install the updated cookbook on the instance.

  5. Choose Update Custom Cookbooks. The command may take a few minutes to complete.

Add the Recipe to the Custom IIS Layer

As with install.rb, the preferred way to handle deployment is to assign deploy.rb to the appropriate lifecycle event. You usually assign deployment recipes to the Deploy event, and they are referred to collectively as Deploy recipes. Assigning a recipe to the Deploy event does not trigger the event. Instead:

  • For new instances, AWS OpsWorks Stacks automatically runs the Deploy recipes after the Setup recipes have finished, so new instances automatically have the current application version.

  • For online instances, you use a deploy command to manually install new or updated applications.

    This command triggers a Deploy event on the stack's instances, which runs the Deploy recipes.

To assign deploy.rb to the layer's Deploy event

  1. Choose Layers in the navigation pane, and then choose Recipes under Layer IISExample.

  2. Under Custom Chef Recipes, add iis-cookbook::deploy to the Deploy recipes box and choose + to add the recipe to the layer.

  3. Choose Save to save the new configuration. The custom Deploy recipes should now include iis-cookbook::deploy.

Add an App

The final piece of the puzzle is to add an app to the stack to represent your application in the AWS OpsWorks Stacks environment. An app includes metadata such as the application's display name, and the data that is required to download the app from its repository.

To add the app to the stack

  1. Choose Apps in the navigation pane, and then choose Add an app.

  2. Configure the app as follows:

    • Name – IIIS-Example-App

    • Repository TypeOther

    • Environment Variables – Add the following three environment variables:

      • S3REGION – The bucket's region (in this case, us-east-1).

      • BUCKET – The bucket name, such as windows-example-app.

      • FILENAME – The file name: default.htm.

  3. Accept the default values for the remaining settings, and then choose Add App to add the app to the stack.

Note

This example uses environment variables to provide the download data. An alternative approach is to use an S3 Archive repository type and provide the file's URL. AWS OpsWorks Stacks will add the information, along with optional data, such as your AWS credentials, to the app's app_source attribute. Your deploy recipe would then need to retrieve the URL from the app attributes and parse it to extract the region, bucket name, and file name.

Deploy the App and Open the Application

AWS OpsWorks Stacks automatically deploys apps to new instances, but not to online instances. Because your instance is already running, you will have to deploy the app manually.

To deploy the app

  1. Choose Apps in the navigation pane, and then choose deploy in the app's Actions column.

  2. Command should be set to Deploy, so click the Deploy button at the lower right of the Deploy App page. The command may take a few minutes to complete.

    After the deployment is complete, you will automatically return to the Apps page. The Status indicator will show successful in green, and the app name will have a green check mark next to it to indicate a successful deployment.

Note

Windows apps are always the Other app type, so deploying the app does the following:

Note

For more information about how to troubleshoot failed deployments or applications, see Debugging Recipes.

The app is now installed. You can open it by choosing Instances in the Navigation pane, and then choosing the instance's public IP address. This sends an HTTP request to the instance, and you should see something like the following in your browser.