ohai (executable)¶

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ohai is the command-line interface for Ohai, a tool that is used to detect attributes on a node, and then provide these attributes to the chef-client at the start of every chef-client run.

Options¶

This command has the following syntax:

$ ohai OPTION

This tool has the following options:

ATTRIBUTE_NAME ATTRIBUTE NAME ...: Use to have Ohai show only output for named attributes.
-c CONFIG, --config CONFIG: The path to a configuration file to use For example: /etc/ohai/config.rb.
-d DIRECTORY, --directory DIRECTORY: The directory in which additional Ohai plugins are located. For example: /my/extra/plugins.
-h, --help: Show help for the command.
-l LEVEL, --log_level LEVEL: The level of logging to be stored in a log file.
-L LOGLOCATION, --logfile LOGLOCATION: The location of the log file.
-v, --version: The version of Ohai.

Examples¶

The following examples show how to use the Ohai command-line tool:

Run a plugin independently of a chef-client run

An Ohai plugin can be run independently of a chef-client run. First, ensure that the plugin is located in the /plugins directory and then use the -f option when running Ohai from the command line. For example, a plugin named sl_installed may look like the following:

Ohai.plugin(:Sl) do
  provides "sl"

  collect_data(:default) do
    sl Mash.new

    if ::File.exist?("/usr/games/sl")
      sl[:installed] = true
    else
      sl[:installed] = false
    end

    # sl[:installed] = ::File.exist?("/usr/games/sl")

  end
end

To run that plugin from the command line, use the following command:

$ ohai --directory /path/to/directory sl

The command will return something similar to:

{
  "sl": {
    "installed": true
  }
}