Chef_Notes.txt

::CHEF::

-Workstation:
Chef comprises of a workstation which is configured to develop the recipes and cookbooks.
It is also configured to run the knife and synchronizes with the chef-repo to keep it up-to-date.

-Server:
Chef server stores recipes/cookbooks and assigns on to the nodes depending on their requirements.

-Nodes:
Clients where the provisioning will happen.


== Either do the above or use "chef-solo"


Configuring Workstation - Installation:

wget https://packages.chef.io/stable/el/7/chefdk-0.14.25-1.el7.x86_64.rpm
rpm -ivh chefdk-0.14.25-1.el7.x86_64.rpm

  What is ChefDK:

The Chef Development Kit contains everything to start with Chef, along with the tools essential for code managing.

-It contains a new command-line tool, "chef"
-The cookbook dependency manager Berkshelf
-The Test Kitchen integration testing framework.
-ChefSpec for testing the cookbook syntax
-Chef tools like Chef Client & Knife


Note: You can install chefdk in one system and that becomes workstation-server-client-aio or remote push it also.




:: Recipe Demo::

  (create a httpd server with index.html)

Recipe file creation:
Add below contents in a file say, apache_installer.rb --

package 'httpd'
service 'httpd' do
action [:enable, :start]
end

file '/var/www/html/index.html' do
content 'Welcome to Apache in Chef'
end


Recipe Execution:

chef-apply apache_installer.rb


Cookbook: is a Combination of chef recipes

Generate Cookbook Skeleton:
  chef generate cookbook httpd_cookbook
  chef generate template httpd_cookbook index.html

Public Cookbook library:  https://supermarket.chef.io/cookbooks

Directly download cookbook or use the Knife command.


Knife:

  knife cookbook site download nagios3


Tree Structure of example cookbook ====

.
|-- attributes
|   `-- default.rb
|-- Berksfile
|-- files
|   `-- default
|       |-- check_logfiles
|       |-- check_service_status.sh
|       `-- log_cfg
|           |-- apache_log.cfg
|           `-- tomcat_log.cfg
|-- Gemfile
|-- metadata.json
|-- metadata.rb
|-- nagios1.png
|-- nagios2.png
|-- README.md
|-- recipes
|   |-- default.rb
|   |-- nagios_check.rb
|   |-- nagios_client.rb
|   `-- nagios_server.rb
`-- templates
    `-- default
        |-- centos_nagios_apache2.conf.erb
        |-- check_ip_address.sh.erb

Berksfile : It is the configuration file, which mainly tells BerkShelf what are the cookbook's dependencies, which can be specified directly inside this file or indirectly through metadata.rb. It also tells Berkshelf where it should look for those dependencies.

Chefignore : It tells Chef which all files should be ignored while uploading a cookbook to the Chef server.

metadata.rb : It contains meta information about you cookbook, such as name, contacts or description. It can also state the cookbook’s dependencies.

README.md : It contains documentation entry point for the repo.

Recipes : Contains the cookbook's recipes. It starts with executing the file default.rb.

default.rb : The default recipe format.

specs : It will be storing the unit test cases of your libraries.

test : It will be storing the unit test cases of your recipes.


- Running cookbooks:

(Example here https://github.com/prasanjit-/chef_cookbook_nagios)

  1. Use Chef-Server/Client Mechanism (Traditional)
  2. Use chef-solo

Using Chef Solo to execute cookbooks:

  a. Just outside cookbook directory run-
    echo "cookbook_path ['$PWD']" > solo.rb

  b. Create a recipes.json for with content as: (check cookbook name from metadata)
    {
  "run_list": [
    "recipe[nagios3::default]",
    "recipe[nagios3::nagios_check]",
    "recipe[nagios3::nagios_client]",
    "recipe[nagios3::nagios_server]"
  ]
}

  c. chef-solo -c solo.rb -j recipes.json