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

Note

A metadata.json file can be edited directly, should temporary changes be required. Any subsequent upload or action that generates metadata will cause the existing metadata.json file to be overwritten with the newly generated metadata. Therefore, any permanent changes to cookbook metadata should be done in the metadata.rb file, and then re-uploaded to the Chef server.

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 'adam@example.com'
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'