Red Hat Enterprise Linux Automation with Ansible

Procedure 5.3. Instructions

1. Review the inventory file in the /home/student/file-review directory. This inventory file defines the servers group, which has the serverb.lab.example.com managed host associated with it.

   1. On workstation, change to the /home/student/file-review directory.

      [student@workstation ~]$ cd ~/file-review/

   2. Display the content of the inventory file.

      [servers]
      serverb.lab.example.com

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2. Identify the facts on serverb.lab.example.com that show the total amount of system memory, and the number of processors.

   Use the setup module to get a list of all the facts for the serverb.lab.example.com managed host. The ansible_processor_count and ansible_memtotal_mb facts provide information about the resource limits of the managed host.

   [student@workstation file-review]$ ansible serverb.lab.example.com -m setup
   serverb.lab.example.com | SUCCESS => {
       "ansible_facts": {
   ...output omitted...
   	"ansible_processor_count": 1,
   ...output omitted...
   	"ansible_memtotal_mb": 821,
   ...output omitted...
       },
       "changed": false
   }

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3. Create a template for the Message of the Day, named motd.j2, in the current directory. When the devops user logs in to serverb.lab.example.com, a message should display that shows the system's total memory and processor count. Use the ansible_facts['memtotal_mb'] and ansible_facts['processor_count'] facts to provide the system resource information for the message.

   System total memory: {{ ansible_facts['memtotal_mb'] }} MiB.
   System processor count: {{ ansible_facts['processor_count'] }}

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4. Create a new playbook file called motd.yml in the current directory. Using the template module, configure the motd.j2 Jinja2 template file previously created to map to the file /etc/motd on the managed hosts. This file has the root user as owner and group, and its permissions are 0644. Using the stat and debug modules, create tasks to verify that /etc/motd exists on the managed hosts and displays the file information for /etc/motd. Use the copy module to place files/issue into the /etc/ directory on the managed host, use the same ownership and permissions as /etc/motd. Use the file module to ensure that /etc/issue.net is a symbolic link to /etc/issue on the managed host. Configure the playbook so that it uses the devops user, and sets the become parameter to true.

   ---
   - name: Configure system
     hosts: all
     remote_user: devops
     become: true
     tasks:
       - name: Configure a custom /etc/motd
         template:
           src: motd.j2
           dest: /etc/motd
           owner: root
           group: root
           mode: 0644
   
       - name: Check file exists
         stat:
           path: /etc/motd
         register: motd
   
       - name: Display stat results
         debug:
           var: motd
   
       - name: Copy custom /etc/issue file
         copy:
           src: files/issue
           dest: /etc/issue
           owner: root
           group: root
           mode: 0644
   
       - name: Ensure /etc/issue.net is a symlink to /etc/issue
         file:
           src: /etc/issue
           dest: /etc/issue.net
           state: link
           owner: root
           group: root
           force: yes

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5. Run the playbook included in the motd.yml file.

   1. Before you run the playbook, use the ansible-playbook --syntax-check command to verify its syntax. If it reports any errors, correct them before moving to the next step. You should see output similar to the following:

      [student@workstation file-review]$ ansible-playbook --syntax-check motd.yml
      
      playbook: motd.yml

   2. Run the playbook included in the motd.yml file.

      [student@workstation file-review]$ ansible-playbook motd.yml
      
      PLAY [Configure system] ****************************************************
      
      TASK [Gathering Facts] *****************************************************
      ok: [serverb.lab.example.com]
      
      TASK [Configure a custom /etc/motd] ****************************************
      changed: [serverb.lab.example.com]
      
      TASK [Check file exists] ***************************************************
      ok: [serverb.lab.example.com]
      
      TASK [Display stat results] ************************************************
      ok: [serverb.lab.example.com] => {
          "motd": {
              "changed": false,
              "failed": false,
      ...output omitted...
      
      TASK [Copy custom /etc/issue file] *****************************************
      changed: [serverb.lab.example.com]
      
      TASK [Ensure /etc/issue.net is a symlink to /etc/issue] ********************
      changed: [serverb.lab.example.com]
      
      PLAY RECAP *****************************************************************
      serverb.lab.example.com    : ok=6    changed=3    unreachable=0    failed=0

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6. Check that the playbook included in the motd.yml file has been executed correctly.

   Log in to serverb.lab.example.com as the devops user, and verify that the /etc/motd and /etc/issue contents are displayed when logging in. Log off when you have finished.

   [student@workstation file-review]$ ssh devops@serverb.lab.example.com
   *------------------------------- PRIVATE SYSTEM -----------------------------*
   *   Access to this computer system is restricted to authorised users only.   *
   *                                                                            *
   *      Customer information is confidential and must not be disclosed.       *
   *----------------------------------------------------------------------------*
   System total memory: 821 MiB.
   System processor count: 1
   Activate the web console with: systemctl enable --now cockpit.socket
   
   This system is not registered to Red Hat Insights. See https://cloud.redhat.com/
   To register this system, run: insights-client --register
   
   Last login: Thu Apr 25 22:09:33 2019 from 172.25.250.9
   [devops@serverb ~]$ logout

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