hostsfile cookbook

hostsfile provides a resource for managing your /etc/hosts (or Windows equivalent) file using Chef.

Requirements

• Chef 12.7 or higher

Attributes

Attribute	Description	Example	Default
ip_address	(name attribute) the IP address for the entry	1.2.3.4
hostname	(required) the hostname associated with the entry	example.com
unique	remove any existing entries that have the same hostname	true	false
aliases	array of aliases for the entry	['www.example.com']	[]
comment	a comment to append to the end of the entry	'internal DNS server'	nil
priority	the relative position of this entry	20	(varies, see Priorities section)

Actions

Please note: In v0.1.2, specifying a hostname or alias that existed in another automatically removed that hostname from the other entry before. In v2.1.0, the unique option was added to give the user case-by-case control of this behavior. For example, given an /etc/hosts file that contains:

1.2.3.4          example.com www.example.com

when the Chef recipe below is converged:

hostsfile_entry '2.3.4.5' do
  hostname  'www.example.com'
  unique    true
end

then the /etc/hosts file will look like this:

1.2.3.4          example.com
2.3.4.5          www.example.com

Not specifying the unique parameter will result in duplicate hostsfile entries.

create

Creates a new hosts file entry. If an entry already exists, it will be overwritten by this one.

hostsfile_entry '1.2.3.4' do
  hostname  'example.com'
  action    :create
end

This will create an entry like this:

1.2.3.4          example.com

create_if_missing

Create a new hosts file entry, only if one does not already exist for the given IP address. If one exists, this does nothing.

hostsfile_entry '1.2.3.4' do
  hostname  'example.com'
  action    :create_if_missing
end

append

Append a hostname or alias to an existing record. If the given IP address doesn't already exist in the hostsfile, this method behaves the same as create. Otherwise, it will append the additional hostname and aliases to the existing entry.

1.2.3.4         example.com www.example.com # Created by Chef

hostsfile_entry '1.2.3.4' do
  hostname  'www2.example.com'
  aliases   ['foo.com', 'foobar.com']
  comment   'Appended by Recipe X'
  action    :append
end

would yield:

1.2.3.4         example.com www.example.com www2.example.com foo.com foobar.com # Created by Chef, Appended by Recipe X

update

Updates the given hosts file entry. Does nothing if the entry does not exist.

hostsfile_entry '1.2.3.4' do
  hostname  'example.com'
  comment   'Updated by Chef'
  action    :update
end

This will create an entry like this:

1.2.3.4           example # Updated by Chef

remove

Removes an entry from the hosts file. Does nothing if the entry does not exist.

hostsfile_entry '1.2.3.4' do
  action    :remove
end

This will remove the entry for 1.2.3.4.

Usage

If you're using Berkshelf, just add hostsfile to your Berksfile:

cookbook 'hostsfile'

Otherwise, install the cookbook from the community site:

knife cookbook site install hostsfile

Have any other cookbooks depend on hostsfile by editing editing the metadata.rb for your cookbook.

# metadata.rb
depends 'hostsfile'

Note that you can specify a custom path to your hosts file in the ['hostsfile']['path'] node attribute. Otherwise, it defaults to sensible paths depending on your OS.

Testing

If you are using ChefSpec to unit test a cookbook that implements the hostsfile_entry resource, this cookbook packages customer matchers that you can use in your unit tests:

• append_hostsfile_entry
• create_hostsfile_entry
• create_hostsfile_entry_if_missing
• remove_hostsfile_entry
• update_hostsfile_entry

For example:

it 'creates a hostsfile entry for the DNS server' do
  expect(chef_run).to create_hostsfile_entry('1.2.3.4')
    .with_hostname('dns.example.com')
end

Priority

Priority is a relatively new addition to the cookbook. It gives you the ability to (somewhat) specify the relative order of entries. By default, the priority is calculated for you as follows:

82. 127.0.0.1
83. ::1
84. 127.0.0.0/8
85. IPV4
86. IPV6
87. default

However, you can override it using the priority option.

License & Authors

• Author:: Seth Vargo (sethvargo@gmail.com)

Copyright 2012-2013, Seth Vargo
Copyright 2012, CustomInk, LLC

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.