About Files

Use the cookbook_file resource to transfer files from a sub-directory of COOKBOOK_NAME/files/ to a specified path located on a host that is running the chef-client. The file is selected according to file specificity, which allows different source files to be used based on the hostname, host platform (operating system, distro, or as appropriate), or platform version. Files that are located in the COOKBOOK_NAME/files/default sub-directory may be used on any platform.

During a chef-client run, the checksum for each local file is calculated and then compared against the checksum for the same file as it currently exists in the cookbook on the Chef server. A file is not transferred when the checksums match. Only files that require an update are transferred from the Chef server to a node.

File Specificity

A cookbook is frequently designed to work across many platforms and is often required to distribute a specific file to a specific platform. A cookbook can be designed to support the distribution of files across platforms, while ensuring that the correct file ends up on each system.

The pattern for file specificity depends on two things: the lookup path and the source attribute. The first pattern that matches is used:

1. /host-$fqdn/$source
2. /$platform-$platform_version/$source
3. /$platform/$source
4. /default/$source

A cookbook may have a /files directory structure like this:

files/
   host-foo.example.com
   ubuntu-10.04
   ubuntu-10
   ubuntu
   redhat-5.8
   redhat-6.4
   ...
   default

and a resource that looks something like the following:

cookbook_file '/usr/local/bin/apache2_module_conf_generate.pl' do
  source 'apache2_module_conf_generate.pl'
  mode '0755'
  owner 'root'
  group 'root'
end

This resource is matched in the same order as the /files directory structure. For a node that is running Ubuntu 10.04, the second item would be the matching item and the location to which the file identified in the cookbook_file resource would be distributed:

host-foo.example.com/apache2_module_conf_generate.pl
ubuntu-10.04/apache2_module_conf_generate.pl
ubuntu-10/apache2_module_conf_generate.pl
ubuntu/apache2_module_conf_generate.pl
default/apache2_module_conf_generate.pl

If the apache2_module_conf_generate.pl file was located in the cookbook directory under files/host-foo.example.com/, the specified file(s) would only be copied to the machine with the domain name foo.example.com.

Host Notation

The naming of folders within cookbook directories must literally match the host notation used for file specificity matching. For example, if a host is named foo.example.com, the folder must be named host-foo.example.com.