lab-07.1-Ordering-methods

Lab 7.1: Ordering methods

We are going to add relationships between resources and classes to help Puppet order the enforcement of our catalog.

In order to allow the idempotent behavior of the include() function, classes do not follow the standard rules of containment. Our first task is to write a simple MySQL wrapper class that will use the functionality of the puppetlabs/mysql module to manage the configuration of MySQL on our nodes. In order for other classes to be able to set relationships on our class, we need to contain the mysql* classes that we use. Your class should manage the MySQL server with a root database user password and bindings for perl and php. Manually remove the packages that are already installed so you can see the class being enforced.

This class might start out like below. Add any containment needed.

class ordering::mysql {
  # How do we make sure these classes don't float off the relationship graph?
  class { '::mysql::server':
    root_password => 'strongpassword',
  }

  class { '::mysql::bindings':
    php_enable  => true,
    perl_enable => true,
  }
}

Include a notify resource in the main ordering class with relationships set so you can see whether you've contained the MySQL classes properly.

notify { 'This should come after the entire MySQL class is enforced':
  require => Class['ordering::mysql'],
}

Prerequisites

1. Install the MySQL module if needed (it should be installed from the last lab).

   puppet module install puppetlabs/mysql

2. Uncomment the following reference in your [control-repo]/Puppetfile.

   mod 'puppetlabs/mysql'

3. Commit and push your control repo changes.

Create a new module

1. Change directory to your [modulepath].

   cd $(puppet agent --configprint environmentpath)/production/modules

2. Create a new module called ordering.

   pdk new module

3. You will see several questions requiring an answer. Enter the answers as you see below:

   Replace the N in studentN with your student number, e.g. student8

   Question	Answer
   Module Name	ordering
   Forge Name	studentN
   Credit author	Student N
   License	Apache-2.0
   Operating systems	RedHat

4. Change directory to your [modulepath]/ordering

   cd ordering

5. Create a new class ordering.

   pdk new class ordering

6. Edit manifests/init.pp

7. Create the mysql class.

   pdk new class mysql

8. Edit manifests/mysql.pp

Validate and commit your code

1. Validate and test the new class:

   pdk validate

2. Commit your changes to the repo.

   • Init your module: git init
   • Add the origin: git remote add origin [email protected]:puppet/ordering.git
   • Checkout the branch: git checkout -b studentN
   • Add the files: git add --all
   • Create a commit: git commit -m "Initial Commit"
   • Push the commit to the Git server: git push origin studentN

3. Update your [control-repo]

   cd ~/control-repo

4. Uncomment the following entry in the [control-repo]/Puppetfile. Replace the “N” in these answers with your student number (for example, student8).

   mod 'ordering',
     :git    => '[email protected]:puppet/ordering.git',
     :branch => 'studentN'
   

5. Commit and push your control repo changes.

   • Add the files: git add Puppetfile
   • Create a commit: git commit -m "Lab 7.1 update"
   • Push the commit to the Git server: git push origin studentN

6. Classify your ordering class in the PE Console.

7. Run puppet agent -t.

   Pay close attention to the order in which resources were enforced.

   Your output should be similar to this

   puppet agent -t
   Notice: Local environment: 'production' doesn't match server specified node environment 'training', switching agent to 'training'.
   Info: Retrieving pluginfacts
   Info: Retrieving plugin
   Info: Loading facts
   Info: Caching catalog for training.puppetlabs.vm
   Info: Applying configuration version 'b76bffe'
   Notice: Hello, my name is training
   Notice: /Stage[main]/Profile::Base/Notify[Hello, my name is training]/message: defined 'message' as 'Hello, my name is training'
   Notice: /Stage[main]/Mysql::Server::Config/File[mysql-config-file]/ensure: defined content as '{md5}4b16ed3375eaa96a2bc1b7aa00c5dd46'
   Notice: /Stage[main]/Mysql::Server::Install/Package[mysql-server]/ensure: created
   Notice: /Stage[main]/Mysql::Server::Service/Service[mysqld]/ensure: ensure changed 'stopped' to 'running'
   Info: /Stage[main]/Mysql::Server::Service/Service[mysqld]: Unscheduling refresh on Service[mysqld]
   Notice: This should come after the entire MySQL class is enforced
   Notice: /Stage[main]/Ordering/Notify[This should come after the entire MySQL class is enforced]/message: defined 'message' as 'This should come after the entire MySQL class is enforced'
   Notice: Applied catalog in 15.66 seconds
   

Solution

Your module structure should resemble

[root@training modules]# tree ordering/
ordering/
├── examples
|   ├── init.pp
|   └── mysql.pp
└── manifests
    ├── init.pp
    └── mysql.pp

Example file: ordering/examples/init.pp

include ordering

Example file: ordering/manifests/init.pp

class ordering {
  include ordering::mysql

  notify { 'This should come after the entire MySQL class is enforced':
    require => Class['ordering::mysql'],
  }
}

Example file: ordering/manifests/mysql.pp

class ordering::mysql {
  class { '::mysql::server':
    root_password    => 'strongpassword',
  }

  class { '::mysql::bindings':
    php_enable  => true,
    perl_enable => true,
  }

  contain mysql::bindings
  contain mysql::server
}

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