Red Hat Enterprise Linux Automation with Ansible

Procedure 2.4. Instructions

The /home/student/playbook-basic working directory has been created on workstation for this exercise. This directory has already been populated with an ansible.cfg configuration file, and also an inventory inventory file, which defines a web group that includes both managed hosts listed above as members.

In this directory, use a text editor to create a playbook named site.yml. This playbook contains one play, which should target members of the web host group. The playbook should use tasks to ensure that the following conditions are met on the managed hosts:

You can use the ansible-doc command to help you understand the keywords needed for each of the modules.

After the playbook is written, verify its syntax and then use ansible-playbook to run the playbook to implement the configuration.

1. Change to the /home/student/playbook-basic directory.

   [student@workstation ~]$ cd ~/playbook-basic
   [student@workstation playbook-basic]$

2. Use a text editor to create a new playbook called /home/student/playbook-basic/site.yml. Start writing a play that targets the hosts in the web host group.

   1. Create and open ~/playbook-basic/site.yml. The first line of the file should be three dashes to indicate the start of the playbook.

      ---

   2. The next line starts the play. It needs to start with a dash and a space before the first keyword in the play. Name the play with an arbitrary string documenting the play's purpose, using the name keyword.

      ---
      - name: Install and start Apache HTTPD

   3. Add a hosts keyword-value pair to specify that the play run on hosts in the inventory's web host group. Make sure that the hosts keyword is indented two spaces so it aligns with the name keyword in the preceding line.

      The complete site.yml file should now appear as follows:

      ---
      - name: Install and start Apache HTTPD
        hosts: web

3. Continue to edit the /home/student/playbook-basic/site.yml file, and add a tasks keyword and the three tasks for your play that were specified in the instructions.

   1. Add a tasks keyword indented by two spaces (aligned with the hosts keyword) to start the list of tasks. Your file should now appear as follows:

      ---
      - name: Install and start Apache HTTPD
        hosts: web
        tasks:

   2. Add the first task. Indent by four spaces, and start the task with a dash and a space, and then give the task a name, such as httpd package is present. Use the yum module for this task. Indent the module keywords two more spaces; set the package name to httpd and the package state to present. The task should appear as follows:

          - name: httpd package is present
            yum:
              name: httpd
              state: present

   3. Add the second task. Match the format of the previous task, and give the task a name, such as correct index.html is present. Use the copy module. The module keywords should set the src key to files/index.html and the dest key to /var/www/html/index.html. The task should appear as follows:

          - name: correct index.html is present
            copy:
              src: files/index.html
              dest: /var/www/html/index.html

   4. Add the third task to start and enable the httpd service. Match the format of the previous two tasks, and give the new task a name, such as httpd is started. Use the service module for this task. Set the name key of the service to httpd, the state key to started, and the enabled key to true. The task should appear as follows:

          - name: httpd is started
            service:
              name: httpd
              state: started
              enabled: true

   5. Your entire site.yml Ansible Playbook should match the following example. Make sure that the indentation of your play's keywords, the list of tasks, and each task's keywords are all correct.

      ---
      - name: Install and start Apache HTTPD
        hosts: web
        tasks:
          - name: httpd package is present
            yum:
              name: httpd
              state: present
      
          - name: correct index.html is present
            copy:
              src: files/index.html
              dest: /var/www/html/index.html
      
          - name: httpd is started
            service:
              name: httpd
              state: started
              enabled: true

      Save the file and exit your text editor.

4. Before running your playbook, run the ansible-playbook --syntax-check site.yml command to verify that its syntax is correct. If it reports any errors, correct them before moving to the next step. You should see output similar to the following:

   [student@workstation playbook-basic]$ ansible-playbook --syntax-check site.yml
   
   playbook: site.yml

5. Run your playbook. Read through the output generated to ensure that all tasks completed successfully.

   [student@workstation playbook-basic]$ ansible-playbook site.yml
   
   PLAY [Install and start Apache HTTPD] ******************************************
   
   TASK [Gathering Facts] *********************************************************
   ok: [serverd.lab.example.com]
   ok: [serverc.lab.example.com]
   
   TASK [httpd package is present] ************************************************
   changed: [serverd.lab.example.com]
   changed: [serverc.lab.example.com]
   
   TASK [correct index.html is present] *******************************************
   changed: [serverd.lab.example.com]
   changed: [serverc.lab.example.com]
   
   TASK [httpd is started] ********************************************************
   changed: [serverd.lab.example.com]
   changed: [serverc.lab.example.com]
   
   PLAY RECAP *********************************************************************
   serverc.lab.example.com    : ok=4    changed=3    unreachable=0    failed=0
   serverd.lab.example.com    : ok=4    changed=3    unreachable=0    failed=0

6. If all went well, you should be able to run the playbook a second time and see all tasks complete with no changes to the managed hosts.

   [student@workstation playbook-basic]$ ansible-playbook site.yml
   
   PLAY [Install and start Apache HTTPD] ******************************************
   
   TASK [Gathering Facts] *********************************************************
   ok: [serverd.lab.example.com]
   ok: [serverc.lab.example.com]
   
   TASK [httpd package is present] ************************************************
   ok: [serverd.lab.example.com]
   ok: [serverc.lab.example.com]
   
   TASK [correct index.html is present] *******************************************
   ok: [serverc.lab.example.com]
   ok: [serverd.lab.example.com]
   
   TASK [httpd is started] ********************************************************
   ok: [serverd.lab.example.com]
   ok: [serverc.lab.example.com]
   
   PLAY RECAP *********************************************************************
   serverc.lab.example.com    : ok=4    changed=0    unreachable=0    failed=0
   serverd.lab.example.com    : ok=4    changed=0    unreachable=0    failed=0

7. Use the curl command to verify that both serverc and serverd are configured as an HTTPD server.

   [student@workstation playbook-basic]$ curl serverc.lab.example.com
   This is a test page.
   [student@workstation playbook-basic]$ curl serverd.lab.example.com
   This is a test page.