Developing Advanced Automation with Red Hat Ansible Automation Platform

Procedure 5.3. Instructions

1. Get familiar with the Ansible project and its current state.

   1. As the student user on the workstation machine, change to the /home/student/inventory-variables directory.

      [student@workstation ~]$ cd ~/inventory-variables/

   2. List the files that the lab command has prepared for you.

      [student@workstation inventory-variables]$ tree -L 1 -F
      .
      ├── ansible.cfg
      ├── ansible-navigator.yml
      ├── deploy_apache.yml 
      ├── deploy_haproxy.yml 
      ├── deploy_webapp.yml 
      ├── inventory.yml 
      ├── roles/
      └── site.yml 

      	The deploy_apache.yml playbook installs the Apache HTTP Server and configures the firewall for the hosts in the web_servers group.
      	The deploy_haproxy.yml playbook installs HAProxy on the lb_servers host group, which only includes the servera host. This playbook also configures the firewall and declares the serverb and serverc hosts as back ends for HAProxy.
      	The deploy_webapp.yml playbook deploys some initial web content on the hosts in the web_servers group.
      	The inventory.yml file declares the serverb and serverc hosts as members of that host group.
      	The global site.yml playbook invokes the three preceding playbooks.

   3. Review the inventory.yml file.

      [student@workstation inventory-variables]$ cat inventory.yml
      lb_servers:
        hosts:
          servera.lab.example.com:
      
      web_servers:
        hosts:
          server[b:c].lab.example.com:

2. The deploy_haproxy.yml playbook declares two variables: haproxy_appservers, which provides the HAProxy configuration; and firewall_rules, which defines the firewall configuration. Move those two variables into inventory variable files.

   1. Review the deploy_haproxy.yml playbook.

      [student@workstation inventory-variables]$ cat deploy_haproxy.yml
      ---
      - name: Ensuring HAProxy is deployed
        hosts: lb_servers
        become: true
        gather_facts: false
      
        tasks:
          - name: Ensure HAProxy is installed and configured
            ansible.builtin.include_role:
              name: haproxy
            vars:
              haproxy_appservers:
                - name: serverb.lab.example.com
                  ip: 172.25.250.11
                  port: 80
                - name: serverc.lab.example.com
                  ip: 172.25.250.12
                  port: 80
      
          - name: Ensure the firewall ports are opened
            ansible.builtin.include_role:
              name: firewall
            vars:
              firewall_rules:
                - port: 80/tcp

   2. Create the group_vars/lb_servers/ directory to hold the variable files for the lb_servers host group.

      [student@workstation inventory-variables]$ mkdir -p group_vars/lb_servers

   3. Create the group_vars/lb_servers/haproxy.yml variable file to store the HAProxy configuration. Copy and paste the haproxy_appservers variable definition from the deploy_haproxy.yml playbook.

      [student@workstation inventory-variables]$ cat group_vars/lb_servers/haproxy.yml
      ---
      haproxy_appservers:
        - name: serverb.lab.example.com
          ip: 172.25.250.11
          port: 80
        - name: serverc.lab.example.com
          ip: 172.25.250.12
          port: 80

   4. Create the group_vars/lb_servers/firewall.yml variable file to store the firewall configuration. Copy and paste the firewall_rules variable definition from the deploy_haproxy.yml playbook.

      [student@workstation inventory-variables]$ cat group_vars/lb_servers/firewall.yml
      ---
      firewall_rules:
        - port: 80/tcp

   5. Edit the deploy_haproxy.yml playbook and then remove the two variables. The resulting file should consist of the following content:

      ---
      - name: Ensuring HAProxy is deployed
        hosts: lb_servers
        become: true
        gather_facts: false
      
        tasks:
          - name: Ensure HAProxy is installed and configured
            ansible.builtin.include_role:
              name: haproxy
      
          - name: Ensure the firewall ports are opened
            ansible.builtin.include_role:
              name: firewall

3. The deploy_apache.yml playbook declares the firewall_rules variable that defines the firewall configuration for the web servers. Move those two variables into an inventory variable file.

   1. Review the deploy_apache.yml playbook.

      [student@workstation inventory-variables]$ cat deploy_apache.yml
      ---
      - name: Ensuring Apache HTTP Server is deployed
        hosts: web_servers
        become: true
        gather_facts: false
      
        tasks:
          - name: Ensure Apache HTTP Server is installed and started
            ansible.builtin.include_role:
              name: apache
      
          - name: Ensure the firewall ports are opened
            ansible.builtin.include_role:
              name: firewall
            vars:
              firewall_rules:
                # Allow HTTP requests from the load_balancer
                - zone: internal
                  service: http
                - zone: internal
                  source: "172.25.250.10"

   2. Create the group_vars/web_servers/ directory to hold the variable files for the web_servers host group.

      [student@workstation inventory-variables]$ mkdir -p group_vars/web_servers

   3. Create the group_vars/web_servers/firewall.yml variable file to store the firewall configuration. Copy and paste the firewall_rules variable definition from the deploy_apache.yml playbook.

      [student@workstation inventory-variables]$ cat group_vars/web_servers/firewall.yml
      ---
      firewall_rules:
        # Allow HTTP requests from the load_balancer
        - zone: internal
          service: http
        - zone: internal
          source: "172.25.250.10"

   4. Edit the deploy_apache.yml playbook and then remove the firewall_rules variable. The resulting file should consist of the following content:

      ---
      - name: Ensuring Apache HTTP Server is deployed
        hosts: web_servers
        become: true
        gather_facts: false
      
        tasks:
          - name: Ensure Apache HTTP Server is installed and started
            ansible.builtin.include_role:
              name: apache
      
          - name: Ensure the firewall ports are opened
            ansible.builtin.include_role:
              name: firewall

4. Edit the inventory.yml static inventory file so that Ansible displays the servera.lab.example.com host as load_balancer in its output. The resulting file should consist of the following content:

   lb_servers:
     hosts:
       load_balancer:
         ansible_host: servera.lab.example.com
   
   web_servers:
     hosts:
       server[b:c].lab.example.com:

5. Run the site.yml playbook and confirm that the web deployment was successful.

   1. Use the ansible-navigator run command to run the site.yml playbook.

      [student@workstation inventory-variables]$ ansible-navigator run \
      > site.yml --mode stdout
      
      PLAY [Ensuring HAProxy is deployed] ********************************************
      
      TASK [Ensure HAProxy is installed and configured] ******************************
      
      TASK [haproxy : Ensure the HAProxy packages are installed] *********************
      changed: [load_balancer]
      
      TASK [haproxy : Ensure HAProxy is started and enabled] *************************
      changed: [load_balancer]
      
      TASK [haproxy : Ensure HAProxy configuration is set] ***************************
      changed: [load_balancer]
      ...output omitted...

   2. Use the curl command to confirm that the HAProxy server distributes the HTTP requests between the two Apache HTTP Servers.

      [student@workstation inventory-variables]$ curl http://servera.lab.example.com
      This is serverb.lab.example.com. (version v1.0)
      [student@workstation inventory-variables]$ curl http://servera.lab.example.com
      This is serverc.lab.example.com. (version v1.0)