Part 3: Understanding Chef Cookbook/Recipe

This article will help you in installing packages on system via chef recipe.

Please refer my previous article on chef:

Part 1	Install/Setup and configure Chef Server/Workstation/Node on CentOS/RHEL 6.4
Part 2	Understanding Chef Cookbook/Recipe.

I) Extending existing Cookbook (cookbook-test) and configure a recipe for deploying Packages.

1. Login to Workstation node which have knife configured.
2. Lets say you have not yet install sendmail on your system, check it out using following command:

      # rpm -qa | grep -v grep | grep -i sendmail

   Note: In case if sendmail is installed and you want to delete it please refer to my rpm page.
3. Now lets create a recipe for a sendmail package.

      # vim /usr/local/src/chef/cookbooks/cookbook-test/recipes/sendmail.rb
        package 'sendmail' do
           action :install
        end

4. To upload a cookbook (cookbook-test) use following command:

      # knife upload cookbooks cookbook-test

5. Once we have upload the cookbook, now is the time to associate it with a Node using “run_list” Knife option:

      # knife node run_list add node1.example.com recipe[cookbook-test::sendmail]
        node1.example.com:
          run_list:
            recipe[cookbook-test]
            recipe[cookbook-test::sendmail]

6. Now login to machine “node1.example.com” and run the following command:

      # chef-client
        Starting Chef Client, version 11.6.2
        [2013-10-25T22:05:20-07:00] INFO: *** Chef 11.6.2 ***
        [2013-10-25T22:05:22-07:00] INFO: Run List is [recipe[cookbook-test], recipe[cookbook-test::sendmail]]
        [2013-10-25T22:05:22-07:00] INFO: Run List expands to [cookbook-test, cookbook-test::sendmail]
        [2013-10-25T22:05:22-07:00] INFO: Starting Chef Run for node1.example.com
        [2013-10-25T22:05:22-07:00] INFO: Running start handlers
        [2013-10-25T22:05:22-07:00] INFO: Start handlers complete.
        resolving cookbooks for run list: ["cookbook-test", "cookbook-test::sendmail"]
        [2013-10-25T22:05:22-07:00] INFO: Loading cookbooks [cookbook-test]
        Synchronizing Cookbooks:
        [2013-10-25T22:05:22-07:00] INFO: Storing updated cookbooks/cookbook-test/recipes/default.rb in the cache.
          - cookbook-test
        Compiling Cookbooks...
        Converging 3 resources
        Recipe: cookbook-test::default
          * group[system-admins] action create[2013-10-25T22:05:22-07:00] INFO: Processing group[system-admins] action create (cookbook-test::default line 9)
         (up to date)
          * user[sachin] action create[2013-10-25T22:05:22-07:00] INFO: Processing user[sachin] action create (cookbook-test::default line 13)
         (up to date)
       Recipe: cookbook-test::sendmail
          * package[sendmail] action install[2013-10-25T22:05:22-07:00] INFO: Processing package[sendmail] action install (cookbook-test::sendmail line 1)
        [2013-10-25T22:06:14-07:00] INFO: package[sendmail] installing sendmail-8.14.4-8.el6 from base repository
   
            - install version 8.14.4-8.el6 of package sendmail
   
        [2013-10-25T22:06:28-07:00] INFO: Chef Run complete in 66.492800835 seconds
        [2013-10-25T22:06:28-07:00] INFO: Running report handlers
        [2013-10-25T22:06:28-07:00] INFO: Report handlers complete
        Chef Client finished, 1 resources updated

7. Check the sendmail rpm is installed on the system.

      # rpm -qa | grep -i send
        sendmail-8.14.4-8.el6.x86_64

II) Now update the recipe to start the service after installing the sendmail package.

1. Login to Workstation node which have knife configured.
2. Edit the recipe file as per following rule:

      # vim /usr/local/src/chef/cookbooks/cookbook-test/recipes/sendmail.rb
        package 'sendmail' do
           action :install
        end
   
        service 'sendmail' do
           action [ :enable,:start ]
        end

3. To upload a cookbook (cookbook-test) use following command:

      # knife upload cookbooks cookbook-test

4. Now login to machine “node1.example.com” and run the following command and check the output of this command:

      # chef-client
        Recipe: system-users::sendmail
          * package[sendmail] action install[2013-10-28T04:12:05-07:00] INFO: Processing package[sendmail] action install (system-users::sendmail line 1)
         (up to date)
          * service[sendmail] action enable[2013-10-28T04:12:10-07:00] INFO: Processing service[sendmail] action enable (system-users::sendmail line 5)
         (up to date)
          * service[sendmail] action start[2013-10-28T04:12:11-07:00] INFO: Processing service[sendmail] action start (system-users::sendmail line 5)
        [2013-10-28T04:12:11-07:00] INFO: service[sendmail] started
   
            - start service service[sendmail]

   NOTE: Please check the comment marked in red.

III) Now update the recipe to delete the sendmail package.

1. Login to Workstation node which have knife configured.
2. Edit the recipe file as per following rule:

      # vim /usr/local/src/chef/cookbooks/cookbook-test/recipes/sendmail.rb
        package 'sendmail' do
           action :remove
        end

3. To upload a cookbook (cookbook-test) use following command:

      # knife upload cookbooks cookbook-test

4. Now login to machine “node1.example.com” and run the following command and check the output of this command:

      # chef-client
        Recipe: system-users::sendmail
          * package[sendmail] action remove[2013-10-28T04:16:59-07:00] INFO: Processing package[sendmail] action remove (system-users::sendmail line 1)
        [2013-10-28T04:17:09-07:00] INFO: package[sendmail] removed
   
            - remove  package sendmail