Red Hat Enterprise Linux Automation with Ansible

Procedure 3.3. Instructions

1. On workstation, as the student user, change into the /home/student/data-facts directory.

   [student@workstation ~]$ cd ~/data-facts
   [student@workstation data-facts]$

2. The Ansible setup module retrieves facts from systems. Run an ad hoc command to retrieve the facts for all servers in the webserver group. The output displays all the facts gathered for servera.lab.example.com in JSON format. Review some of the variables displayed.

   [student@workstation data-facts]$ ansible webserver -m setup
   ...output omitted...
   servera.lab.example.com | SUCCESS => {
       "ansible_facts": {
           "ansible_all_ipv4_addresses": [
               "172.25.250.10"
           ],
           "ansible_all_ipv6_addresses": [
               "fe80::2937:3aa3:ea8d:d3b1"
           ],
   ...output omitted...

3. On workstation, create a fact file named /home/student/data-facts/custom.fact. The fact file defines the package to install and the service to start on servera. The file should read as follows:

   [general]
   package = httpd
   service = httpd
   state = started
   enabled = true

4. Create the setup_facts.yml playbook to make the /etc/ansible/facts.d remote directory and to save the custom.fact file to that directory.

   ---
   - name: Install remote facts
     hosts: webserver
     vars:
       remote_dir: /etc/ansible/facts.d
       facts_file: custom.fact
     tasks:
       - name: Create the remote directory
         file:
           state: directory
           recurse: yes
           path: "{{ remote_dir }}"
       - name: Install the new facts
         copy:
           src: "{{ facts_file }}"
           dest: "{{ remote_dir }}"

5. Run an ad hoc command with the setup module. Search for the ansible_local section in the output. There should not be any custom facts at this point.

   [student@workstation data-facts]$ ansible webserver -m setup
   servera.lab.example.com | SUCCESS => {
       "ansible_facts": {
   ...output omitted...
           "ansible_local": {}
   ...output omitted...
       },
       "changed": false
   }

6. Before running the playbook, verify its syntax is correct by running ansible-playbook --syntax-check. If it reports any errors, correct them before moving to the next step. You should see output similar to the following:

   [student@workstation data-facts]$ ansible-playbook --syntax-check setup_facts.yml
   
   playbook: setup_facts.yml

7. Run the setup_facts.yml playbook.

   [student@workstation data-facts]$ ansible-playbook setup_facts.yml
   
   PLAY [Install remote facts] ****************************************************
   
   TASK [Gathering Facts] *********************************************************
   ok: [servera.lab.example.com]
   
   TASK [Create the remote directory] *********************************************
   changed: [servera.lab.example.com]
   
   TASK [Install the new facts] ***************************************************
   changed: [servera.lab.example.com]
   
   PLAY RECAP *********************************************************************
   servera.lab.example.com    : ok=3    changed=2    unreachable=0    failed=0

8. It is now possible to create the main playbook that uses both default and user facts to configure servera. Over the next several steps, you will add to the playbook file. Create the playbook playbook.yml with the following:

   ---
   - name: Install Apache and starts the service
     hosts: webserver

9. Continue editing the playbook.yml file by creating the first task that installs the httpd package. Use the user fact for the name of the package.

     tasks:
       - name: Install the required package
         yum:
           name: "{{ ansible_facts['ansible_local']['custom']['general']['package'] }}"
           state: latest

10. Create another task that uses the custom fact to start the httpd service.

        - name: Start the service
          service:
            name: "{{ ansible_facts['ansible_local']['custom']['general']['service'] }}"
            state: "{{ ansible_facts['ansible_local']['custom']['general']['state'] }}"
            enabled: "{{ ansible_facts['ansible_local']['custom']['general']['enabled'] }}"

11. When completed with all the tasks, the full playbook should look like the following. Review the playbook and ensure all the tasks are defined.

    ---
    - name: Install Apache and starts the service
      hosts: webserver
    
      tasks:
        - name: Install the required package
          yum:
            name: "{{ ansible_facts['ansible_local']['custom']['general']['package'] }}"
            state: latest
    
        - name: Start the service
          service:
            name: "{{ ansible_facts['ansible_local']['custom']['general']['service'] }}"
            state: "{{ ansible_facts['ansible_local']['custom']['general']['state'] }}"
            enabled: "{{ ansible_facts['ansible_local']['custom']['general']['enabled'] }}"

12. Before running the playbook, use an ad hoc command to verify the httpd service is not currently running on servera.

    [student@workstation data-facts]$ ansible servera.lab.example.com -m command \
    > -a 'systemctl status httpd'
    servera.lab.example.com | FAILED | rc=4 >>
    Unit httpd.service could not be found.non-zero return code

13. Verify the syntax of the playbook by running ansible-playbook --syntax-check. If it reports any errors, correct them before moving to the next step. You should see output similar to the following:

    [student@workstation data-facts]$ ansible-playbook --syntax-check playbook.yml
    
    playbook: playbook.yml

14. Run the playbook using the ansible-playbook command. Watch the output as Ansible installs the package and then enables the service.

    [student@workstation data-facts]$ ansible-playbook playbook.yml
    
    PLAY [Install Apache and start the service] ************************************
    
    TASK [Gathering Facts] *********************************************************
    ok: [servera.lab.example.com]
    
    TASK [Install the required package] ********************************************
    changed: [servera.lab.example.com]
    
    TASK [Start the service] *******************************************************
    changed: [servera.lab.example.com]
    
    PLAY RECAP *********************************************************************
    servera.lab.example.com    : ok=3    changed=2    unreachable=0    failed=0

15. Use an ad hoc command to execute systemctl to determine whether the httpd service is now running on servera.

    [student@workstation data-facts]$ ansible servera.lab.example.com -m command \
    > -a 'systemctl status httpd'
    servera.lab.example.com | CHANGED | rc=0 >>
    ● httpd.service - The Apache HTTP Server
       Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
       Active: active (running) since Mon 2019-05-27 07:50:55 EDT; 50s ago
         Docs: man:httpd.service(8)
     Main PID: 11603 (httpd)
       Status: "Running, listening on: port 80"
        Tasks: 213 (limit: 4956)
       Memory: 24.1M
       CGroup: /system.slice/httpd.service
    ...output omitted...