Opscode distributes Ohai as a Gem, available from http://rubygems.org/

If you're running Windows, see Installing Ohai on Windows for more information.

Install Gem

Ohai Version Dependencies

Chef version 0.10 requires Ohai Version 0.6.x or greater, and will not function with earlier versions.

Add Rubygems.org's gem server to your local sources.

Update Gem Sources

Install the Gem.

Install Ohai

This will also install Ohai's dependency gems, json, extlib and systemu.

We use GitHub for sharing our source code, so to install the source from Git:

clone git repository

Install the gem with rake.

rake install

See the README.rdoc included in the repository (or on the GitHub page) for more about Ohai development. Also read about contributing to Opscode projects

Node data from ohai is provided to Chef via an object named node.

When used with Chef, Ohai JSON output is reported back via "automatic" node attributes to update the node object on the chef-server.

Ohai can also be run outside of Chef, so you can query your system for various data.

When run standalone, Ohai will print out a JSON data blob for all the known data about your system.

Use as a Library

You can use Ohai as a library within a ruby program or script.