Adding classes quick start guide

In this quick start guide, you’ll apply the apache class to your agent node, which will allow you to launch the default Apache virtual host on your agent node.

Complete a basic classification workflow

Every module contains one or more classes. Classes are named chunks of Puppet code and are the primary means by which Puppet Enterprise configures nodes. The puppetlabs-apache module you installed in the Module installation quick start guide contains a class called apache.

Before you begin, make sure you’ve installed a monolithic PE deployment, and have installed at least one *nix agent node and the puppetlabs-apache module.

Step 1: Create a new node group

You could assign classes to individual nodes one at a time, but chances are, each of your classes needs to be applied to more than one node. By creating a node group, you can apply a class to many nodes at once.

  1. In the PE console, click Classification, and click Add group.

  2. Specify options for the new node group:
    • Parent name – Select All Nodes.
    • Group name – Enter a name that describes the role of this node group, such as apache_example.
    • Environment – Select production.
    • Environment group – Don’t select this option.
  3. Click Add.

Step 2: Add nodes to the node group

To add nodes to a node group, create rules that define which nodes should be included in the group.

  1. Click the apache_example group.
  2. From the Rules tab, in the Certname area, in the Node name field, enter the name of your PE agent node.
  3. Click Pin node.
  4. Commit changes.
  5. Repeat steps 5-7 for any other nodes you want to add.

FAQs

Step 3: Add the apache class to the node group

Now that you’ve created a node group, add classes to give the matching nodes purpose.

  1. Unless you have navigated elsewhere in the console, the apache_example node group should still be displayed in the Classification page. On the Classes tab, in the Class name field, begin typing apache, and select it from the autocomplete list.

  2. Click Add class, and commit changes.

The apache class now appears in the list of classes for your agent. You can see this list by clicking Inventory and then clicking your node in the Inventory list. When the page opens with your node’s details, click the Classes tab.

  1. Apply your changes. From the command line on your agent, run puppet agent -t.

  2. To see your changes in action, navigate to /var/www/html/, and create a file named index.html.

  3. Open index.html with the text editor of your choice and add some content (for example, “Hello, World!”).

  4. From the command line of your agent node, run puppet agent -t. This configures the node using the newly assigned class.

  5. Wait one or two minutes.

  6. Open a browser and enter the IP address for the agent node, adding port 80 on the end, as in http://myagentnodeIP:80/. The contents of /var/www/html/index.html are displayed.

Step 4: Edit class parameters in the console

You can use the console to modify the values of a class’s parameters without editing the module code directly.

  1. In the console, click Classification, and find and select the apache_example group.
  2. On the Classes tab, find apache in the list of classes.
  3. From the Parameter Name drop-down list, choose the parameter you want to edit. For this example, select docroot.

    Note: The grey text that appears as values for some parameters is the default value, which can be either a literal value or a Puppet variable. You can restore this value by selecting Discard changes after you have added the parameter.

  4. In the Value field, enter /var/www.
  5. Click Add parameter, and commit changes.
  6. From the command line of your PE-managed node, run puppet agent -t.

    This triggers a Puppet run, and Puppet Enterprise creates the new configuration.

You have set the Apache web server’s root directory to /var/www instead of its default /var/www/html. If you refresh http://myagentnodeIP:80/in your web browser, it shows the list of files in /var/www. If you click html, the browser again shows the contents of /var/www/html/index.html.

Puppet Enterprise is now managing the default Apache vhost on your agent node. Next, you’ll learn how to manage users with PE, and how to set permissions for each user or group of users. Click here when you’re ready to move forward.

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