Roles¶

---
### defaults/main.yml
###
### This file contain the variables for the Demo lab
###

# Defaults file for codewizard_lab_role
motd_message: "Welcome to Ansible Roles Lab"

### The package we wish to install on the servers
apt_packages:
  - python3
  - nodejs
  - npm

# Packages to verify that they were installed
apt_packages_verify:
  - python3
  - npm

package_state: latest

### templates/motd.j2

_____             _          _    _  _                      _ 
/  __ \           | |        | |  | |(_)                    | |
| /  \/  ___    __| |  ___   | |  | | _  ____ __ _  _ __  __| |
| |     / _ \  / _` | / _ \  | |/\| || ||_  // _` || '__|/ _` |
| \__/\| (_) || (_| ||  __/  \  /\  /| | / /| (_| || |  | (_| |
\____/ \___/  \__,_| \___|   \/  \/ |_|/___|\__,_||_|   \__,_|

{{ motd_message }}

System information:
-------------------

OS:         {{ ansible_distribution }} {{ ansible_distribution_version }}
Hostname:   {{ inventory_hostname }}

{{ custom_message | default('') }}

### templates/node-server.j2
const
    // Set the server port which will be listening to
    // Those 2 values are passed from the env file
    SERVER_PORT = 5000,
    SERVER_NAME = "{{ inventory_hostname }}";

// Create the basic http server
require('http')
    .createServer((request, response) => {

        // Send reply to user
        response.end(`<h1>Hello from ${SERVER_NAME}.</h1>`);

    }).listen(SERVER_PORT, () => {
        // Notify users that the server is up and running
        console.log(`${SERVER_NAME} is up. 
            Please click or point your browser to:
            http://localhost:${SERVER_PORT}`);
    });

### tasks/pre-requirements.yaml
---
- name: Install Packages
  ansible.builtin.apt:
    name: "{{ item }}"
    state: "{{ package_state }}"
  # Loop over the required packages to install
  with_items: "{{ apt_packages }}"

- name: Verify Packages Installation
  ansible.builtin.command: "{{ item }} --version"
  register: packages_version
  with_items: "{{ apt_packages_verify }}"

- name: Print package version
  ansible.builtin.debug:
    msg: "{{ item.stdout_lines  }}"
  with_items: "{{ packages_version.results }}"

### tasks/node-server.yaml
---
- name: Copy Node server
  ansible.builtin.template:
    src: templates/node-server.j2
    dest: /node-server.js
    mode: 600
  become: true
  become_method: ansible.builtin.su

- name: Install "pm2" node.js package.
  community.general.npm:
    name: "pm2"
    global: true
  become: true
  become_method: ansible.builtin.su

- name: Get running node processes
  shell: "ps -ef | grep -v grep | grep -w node | awk '{print $2}'"
  register: running_processes

- name: Kill running node server (if any)
  shell: "kill {{ item }}"
  with_items: "{{ running_processes.stdout_lines }}"

- name: Wait for the process to die
  wait_for:
    path: "/proc/{{ item }}/status"
    state: absent
  with_items: "{{ running_processes.stdout_lines }}"
  ignore_errors: true
  register: killed_processes

- name: Force kill stuck processes
  shell: "kill -9 {{ item }}"
  with_items: "{{ killed_processes.results | select('failed') | map(attribute='item') | list }}"

- name: Start Node server
  ansible.builtin.command:
    chdir: /
    cmd: "pm2 start -f /node-server.js"
  register: server_status
  changed_when: server_status.rc != 0

- name: Print server status
  ansible.builtin.debug:
    msg: "{{ server_status.stdout_lines }}"
  when: server_status.rc == 0

- name: Check server
  uri:
    url: http://localhost:5000
    method: GET
    status_code: 200
  register: server_status

- name: Print server status
  ansible.builtin.debug:
    msg: "{{ server_status.status }} - {{ server_status.msg }}"
  ```

  ```yaml
  ### tasks/motd.j2
  ---
  - name: Copy template
    ansible.builtin.template:
      src: templates/motd.j2
      dest: /etc/motd
      mode: preserve
    become: true
    become_method: ansible.builtin.su
  ```

  ```yaml
  ### tasks/main.yml
  ---
  - name: Include Pre-Requirements task
    ansible.builtin.include_tasks:
      file: pre-requirements.yaml

  - name: Include motd task
    ansible.builtin.include_tasks:
      file: motd.yaml

  - name: Deploy node server
    ansible.builtin.include_tasks:
      file: node-server.yaml
  ```        

#### 02.04. Create the playbook for the role

```yaml
### 009-role-playbook.yml
---
###
### The playbook for using our role
### 
- name: Executing codewizard_lab_role
  hosts: all
  become: true
  become_method: ansible.builtin.su

  roles:
    - codewizard_lab_role