Cookbook Directories and Metadata

The cookbooks/ directory is used to store the cookbooks that are used by the chef-client when configuring the various systems in the organization. This directory contains the cookbooks that are used to configure systems in the infrastructure. Each cookbook can be configured to contain cookbook-specific copyright, email, and license data.

To configure cookbook-specific copyright, email, and license data, add the following to the knife.rb file in the chef-repo:

cookbook_copyright "Example, Com."
cookbook_email     "[email protected]"
cookbook_license   "apachev2"

where the cookbook_copyright and cookbook_email are specific to the organization and cookbook_license is either apachev2 or none. These settings will be used in the default recipe and in corresponding values in the metadata.rb file, but can be modified in those locations as well (if they should be different from the default values contained in the knife.rb file.)

Work with Cookbooks

Use the following knife subcommands to create, install, and/or download cookbooks.

Create

To create a cookbook (including all default components), run the following command:

$ knife cookbook create COOKBOOK_NAME

where COOKBOOK_NAME is the name of the cookbook that will be created. Any unneeded directory components can be left unused or deleted, if preferred.

Install

To download a cookbook when git is used for version source control, run the following command:

$ knife cookbook site install COOKBOOK_NAME

where COOKBOOK_NAME is the name of a cookbook on https://supermarket.chef.io. This will start a process that:

• downloads the cookbook from https://supermarket.chef.io as a tar.gz archive
• ensures that its using the git master branch, and then checks out the cookbook from a vendor branch (creating a new vendor branch, if required)
• removes the old (existing) version
• expands the tar.gz archive and adds the expanded files to the git index and commits
• creates a tag for the version that was downloaded
• checks out the master branch
• merges the cookbook into the master (to ensure that any local changes or modifications are preserved)

Download

To download a cookbook when git is not used for version source control, run the following command:

$ knife cookbook site download COOKBOOK_NAME

where COOKBOOK_NAME is the name of a cookbook on https://supermarket.chef.io. This will download the tar.gz file associated with the cookbook and will create a file named COOKBOOK_NAME.tar.gz in the current directory (e.g., ~/chef-repo). Once downloaded, using a version source control system is recommended.

About Cookbook Metadata

Every cookbook requires a small amount of metadata. A file named metadata.rb is located at the top of every cookbook directory structure. The contents of the metadata.rb file provides hints to the Chef server to help ensure that cookbooks are deployed to each node correctly.

Error Messages

The Chef server will only try to distribute the cookbooks that are needed to configure an individual node. This is determined by identifying the roles and recipes that are assigned directly to that system, and then to expand the list of dependencies, and then to deliver that entire set to the node. In some cases, if the dependency is not specified in the cookbook’s metadata, the Chef server may not treat that dependency as a requirement, which will result in an error message. If an error message is received from the Chef server about cookbook distribution, verify the depends entries in the metadata.rb file, and then try again.

metadata.rb

Every cookbook requires a small amount of metadata. A file named metadata.rb is located at the top of every cookbook directory structure. The contents of the metadata.rb file provides hints to the Chef server to help ensure that cookbooks are deployed to each node correctly.

A metadata.rb file is:

• Located at the top level of a cookbook’s directory structure
• Compiled whenever a cookbook is uploaded to the Chef server or when the knife cookbook metadata subcommand is run, and then stored as JSON data
• Created automatically by knife whenever the knife cookbook create subcommand is run
• Edited using a text editor, and then re-uploaded to the Chef server as part of a cookbook upload

Settings

This configuration file has the following settings:

attribute

The list of attributes that are required to configure a cookbook. An attribute name is required, followed by any of these options: display_name (the name that appears in the user interface), description (a short description), choice (an array of choices that are presented to a user), calculated (the default value is calculated by the recipe), type (the type of value, either string, array, or hash), required (the level of user input, either required, recommended, or optional), recipes (an array of recipes), or default (the attribute’s default value).

For example:

attribute 'pets/cat/name',
  :display_name => 'Cat Name',
  :description => 'The name of your cat',
  :choice => \[
    'kitty kitty',
    'peanut',
    'einstein',
    'honey' \],
  :type => 'string',
  :required => 'recommended',
  :recipes => \[ 'cats::eat' \],
  :default => 'kitty kitty'

depends

Show that a cookbook has a dependency on another cookbook. Use a version constraint to define dependencies for cookbook versions: < (less than), <= (less than or equal to), = (equal to), >= (greater than or equal to; also known as “optimistically greater than”, or “optimistic”), ~> (approximately greater than; also known as “pessimistically greater than”, or “pessimistic”), or > (greater than). This field requires that a cookbook with a matching name and version exists on the Chef server. When the match exists, the Chef server includes the dependency as part of the set of cookbooks that are sent to the node when the chef-client runs. It is very important that the depends field contain accurate data. If a dependency statement is inaccurate, the chef-client may not be able to complete the configuration of the system.

For example, to set a dependency a cookbook named cats:

depends 'cats'

or, to set a dependency on the same cookbook, but only when the version is less than 1.0:

depends 'cats', '< 1.0'

description

A short description of a cookbook and its functionality.

For example:

description 'A fancy cookbook that manages a herd of cats!'

license

The type of license under which a cookbook is distributed: Apache v2.0, GPL v2, GPL v3, MIT, or license 'Proprietary - All Rights Reserved (default). Please be aware of the licenses for files inside of a cookbook and be sure to follow any restrictions they describe.

For example:

license 'Apache v2.0'

or:

license 'GPL v3'

or:

license 'MIT'

or:

license 'Proprietary - All Rights Reserved'

long_description

A longer description that ideally contains full instructions on the proper use of a cookbook, including definitions, libraries, dependencies, and so on. There are two ways to use this field: with the contents embedded in the field itself or with the contents pulled from a file at a specified path, such as a README.rdoc located at the top of a cookbook directory.

For example, to embed the long description within the field itself:

long_description <<-EOH
= DESCRIPTION:

Complete Debian/Ubuntu style Apache2 configuration.

= REQUIREMENTS:

Debian or Ubuntu preferred.

Red Hat/CentOS and Fedora can be used but will be converted to
a Debian/Ubuntu style Apache as it's far easier to manage
with Chef.

= ATTRIBUTES:

The file attributes/apache.rb contains the following attribute
types:

* platform specific locations and settings.
* general settings
* pre-fork attributes
* worker attributes

General settings and pre-fork/worker attributes are tunable.
EOH

Or to read the contents from a specified file:

long_description IO.read(File.join
  (File.dirname(__FILE__), 'README.rdoc')
)

maintainer

The name of the person responsible for maintaining a cookbook, either an individual or an organization.

For example:

maintainer 'Adam Jacob'

maintainer_email

The email address for the person responsible for maintaining a cookbook. Only one email can be listed here, so if this needs to be forwarded to multiple people consider using an email address that is already setup for mail forwarding.

For example:

maintainer_email '[email protected]'

name

Required. The name of the cookbook.

For example:

name 'cats'

provides

Add a recipe, definition, or resource that is provided by this cookbook, should the auto-populated list be insufficient.

For example, for recipes:

provides 'cats::sleep'
provides 'cats::eat'

For definitions:

provides 'here(:kitty, :time_to_eat)'

And for resources:

provides 'service[snuggle]'

recipe

A description for a recipe, mostly for cosmetic value within the Chef server user interface.

For example:

recipe 'cats::sleep', 'For a crazy 20 hours a day.'

or:

recipe 'cats::eat', 'When they are not sleeping.'

supports

Show that a cookbook has a supported platform. Use a version constraint to define dependencies for platform versions: < (less than), <= (less than or equal to), = (equal to), >= (greater than or equal to), ~> (approximately greater than), or > (greater than). To specify more than one platform, use more than one supports field, once for each platform.

For example, to support every version of Ubuntu:

supports 'ubuntu'

or, to support versions of Ubuntu greater than or equal to 12.04:

supports 'ubuntu', '>= 12.04'

or, to support only Ubuntu 14.10:

supports 'ubuntu', '= 14.10'

version

The current version of a cookbook. Version numbers always follow a simple three-number version sequence.

For example:

version '2.0.0'