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

Example 1: Installing Packages

Package installation is one of the more common uses of recipes and can be quite simple, depending on the package. For example, the following recipe installs Git on a Linux system.

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package 'git' do action :install end

The package resource handles package installation. For this example, you don't need to specify any attributes. The resource name is the default value for the package_name attribute, which identifies the package. The install action directs the provider to install the package. You could make the code even simpler by skipping install; it's the package resource's default action. When you run the recipe, Chef uses the appropriate provider to install the package. On the Ubuntu system that you will use for the example, the provider installs Git by calling apt-get.

Note

Installing software on a Windows system requires a somewhat different procedure. For more information, see Installing Windows Software.

To use Test Kitchen to run this recipe in Vagrant, you first need to set up a cookbook and initialize and configure Test Kitchen. The following is for a Linux system, but the procedure is essentially similar for Windows and Macintosh systems. Start by opening a Terminal window; all of the examples in this chapter use command-line tools.

To prepare the cookbook

  1. In your home directory, create a subdirectory named opsworks_cookbooks, which will contain all the cookbooks for this chapter. Then create a subdirectory for this cookbook named installpkg and navigate to it.

  2. In installpkg, create a file named metadata.rb that contains the following code.

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    name "installpkg" version "0.1.0"

    For simplicity, the examples in this chapter just specify the cookbook name and version, but metadata.rb can contain a variety of cookbook metadata. For more information, see About Cookbook Metadata.

    Note

    Make sure to create metadata.rb before you initialize Test Kitchen; it uses the data to create the default configuration file.

  3. In installpkg, run kitchen init, which initializes Test Kitchen and installs the default Vagrant driver.

  4. The kitchen init command creates a YAML configuration file in installpkg named .kitchen.yml. Open the file in your favorite text editor. The .kitchen.yml file includes a platforms section that specifies which systems to run the recipes on. Test Kitchen creates an instance and runs the specified recipes on each platform.

    Note

    By default, Test Kitchen runs recipes one platform at a time. If you add a -p argument to any command that creates an instance, Test Kitchen will run the recipes on every platform, in parallel.

    A single platform is sufficient for this example, so edit .kitchen.yml to remove the centos-6.4 platform. Your .kitchen.yml file should now look like this:

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    --- driver: name: vagrant provisioner: name: chef_solo platforms: - name: ubuntu-12.04 suites: - name: default run_list: - recipe[installpkg::default] attributes:

    Test Kitchen runs only those recipes that are in the .kitchen.yml run list. You identify recipes by using the [cookbook_name::recipe_name] format, where recipe_name omits the .rb extension. Initially, the .kitchen.yml run list contains the cookbook's default recipe, installpkg::default. That's the recipe that you are going to implement, so you don't need to modify the run list.

  5. Create a subdirectory of installpkg named recipes.

    If a cookbook contains recipes—most do—they must be in the recipes subdirectory.

You can now add the recipe to the cookbook and use Test Kitchen to run it on an instance.

To run the recipe

  1. Create a file named default.rb that contains the Git installation example code from the beginning of the section and save it to the recipes subdirectory.

  2. In the installpkg directory, run kitchen converge. This command starts a new Ubuntu 12.04 LTS instance in Vagrant, copies your cookbooks to the instance, and initiates a Chef run to execute the recipes in the .kitchen.yml run list.

  3. To verify that the recipe was successful, run kitchen login, which opens an SSH connection to the instance. Then run git --version to verify that Git was successfully installed. To return to your workstation, run exit.

  4. When you are finished, run kitchen destroy to shut down the instance. The next example uses a different cookbook.

This example was a good way to get started, but it is especially simple. Other packages can be more complicated to install; you might need to do any or all of the following:

  • Create and configure a user.

  • Create one or more directories for data, logs, and so on.

  • Install one or more configuration files.

  • Specify a different package name or attribute values for different operating systems.

  • Start a service and then restart it as needed.

The following examples describe how to address these issues, along with some other useful operations.