19.4. Creating a Quadlet application with secrets by using the podman RHEL system role

Procedure

1. Display the contents of the certificate and private key files:

   $ cat ~/certificate.pem
   -----BEGIN CERTIFICATE-----
   ...
   -----END CERTIFICATE-----
   
   $ cat ~/key.pem
   -----BEGIN PRIVATE KEY-----
   ...
   -----END PRIVATE KEY-----

   You require this information in a later step.

2. Store your sensitive variables in an encrypted file:

   1. Create the vault:

      $ ansible-vault create ~/vault.yml
      New Vault password: <vault_password>
      Confirm New Vault password: <vault_password>

   2. After the ansible-vault create command opens an editor, enter the sensitive data in the <key>: <value> format:

      root_password: <root_password>
      certificate: |-
        -----BEGIN CERTIFICATE-----
        ...
        -----END CERTIFICATE-----
      key: |-
        -----BEGIN PRIVATE KEY-----
        ...
        -----END PRIVATE KEY-----

      Ensure that all lines in the certificate and key variables start with two spaces.

   3. Save the changes, and close the editor. Ansible encrypts the data in the vault.

3. Create a playbook file, for example, ~/playbook.yml, with the following content:

   - name: Deploy a wordpress CMS with MySQL database
     hosts: managed-node-01.example.com
     vars_files:
       - ~/vault.yml
     tasks:
     - name: Create and run the container
       ansible.builtin.include_role:
         name: redhat.rhel_system_roles.podman
       vars:
         podman_create_host_directories: true
         podman_activate_systemd_unit: false
         podman_quadlet_specs:
           - name: quadlet-demo
             type: network
             file_content: |
               [Network]
               Subnet=192.168.30.0/24
               Gateway=192.168.30.1
               Label=app=wordpress
           - file_src: quadlet-demo-mysql.volume
           - template_src: quadlet-demo-mysql.container.j2
           - file_src: envoy-proxy-configmap.yml
           - file_src: quadlet-demo.yml
           - file_src: quadlet-demo.kube
             activate_systemd_unit: true
         podman_firewall:
           - port: 8000/tcp
             state: enabled
           - port: 9000/tcp
             state: enabled
         podman_secrets:
           - name: mysql-root-password-container
             state: present
             skip_existing: true
             data: "{{ root_password }}"
           - name: mysql-root-password-kube
             state: present
             skip_existing: true
             data: |
               apiVersion: v1
               data:
                 password: "{{ root_password | b64encode }}"
               kind: Secret
               metadata:
                 name: mysql-root-password-kube
           - name: envoy-certificates
             state: present
             skip_existing: true
             data: |
               apiVersion: v1
               data:
                 certificate.key: {{ key | b64encode }}
                 certificate.pem: {{ certificate | b64encode }}
               kind: Secret
               metadata:
                 name: envoy-certificates

   The procedure creates a WordPress content management system paired with a MySQL database. The podman_quadlet_specs role variable defines a set of configurations for the Quadlet, which refers to a group of containers or services that work together in a certain way. It includes the following specifications:

   • The Wordpress network is defined by the quadlet-demo network unit.
   • The volume configuration for MySQL container is defined by the file_src: quadlet-demo-mysql.volume field.
   • The template_src: quadlet-demo-mysql.container.j2 field is used to generate a configuration for the MySQL container.
   • Two YAML files follow: file_src: envoy-proxy-configmap.yml and file_src: quadlet-demo.yml. Note that .yml is not a valid Quadlet unit type, therefore these files will just be copied and not processed as a Quadlet specification.

   • The Wordpress and envoy proxy containers and configuration are defined by the file_src: quadlet-demo.kube field. The kube unit refers to the previous YAML files in the [Kube] section as Yaml=quadlet-demo.yml and ConfigMap=envoy-proxy-configmap.yml.

     For details about all variables used in the playbook, see the /usr/share/ansible/roles/rhel-system-roles.podman/README.md file on the control node.

4. Validate the playbook syntax:

   $ ansible-playbook --syntax-check --ask-vault-pass ~/playbook.yml

   Note that this command only validates the syntax and does not protect against a wrong but valid configuration.

5. Run the playbook:

   $ ansible-playbook --ask-vault-pass ~/playbook.yml