Road-to-DevOps/Pepiniere/ansible/Formation/travaux-pratiques/tp-ansible-roles.md

## TP Roles

* Reprendre le TP Wordpress et le découper en Roles.

* Exemple de rôles pouvant être définis :  
<small>mariadb, db, httpd, apache, wordpress...</small>

* Gérer les variables par défaut.

* Gérer les variables liées à l'environnement.

* Gérer la dépendances de roles entre l'applicatif et le serveur web.



Arborescence du projet :

<!-- .slide: data-state="small-code" -->
```none
ansible
├── playbook.yaml
├── inventories
│   └── formation
│       ├── group_vars
│       │   └── wordpress.yaml    <--- vars mariadb, wordpress
│       └── hosts
└── roles
    ├── apache
    │   ├── handlers
    │   │   └── main.yaml
    │   └── tasks
    │       └── main.yaml
    ├── mariadb
    │   ├── defaults
    │   │   └── main.yaml         <--- vars par défaut mariadb
    │   └── tasks
    │       ├── add-database.yaml
    │       ├── install.yaml
    │       └── main.yaml
    └── wordpress
        ├── meta
        |   └── main.yaml        <--- dépendances de wordpress
        └── tasks
            ├── configure.yaml
            ├── install.yaml
            └── main.yaml
```


`inventories/formation/hosts`
```ini
ansible-1 ansible_host=192.168.56.102
ansible-2 ansible_host=192.168.56.103

[wordpress]
ansible-1
ansible-2

[all:vars]
ansible_become=yes
ansible_become_pass=ansible
```


`inventories/formation/group_vars/wordpress.yaml`
```yaml
DB_NAME: wordpress
DB_USER: wordpressuser
DB_PASSWORD: "12345"
DB_HOST: "{{ hostvars['ansible-2']['ansible_host'] }}"
WEB_HOST: "{{ hostvars['ansible-1']['ansible_host'] }}"
```


`playbook.yaml`
```yaml
- hosts: ansible-2
  roles:
   - role: mariadb

- hosts: ansible-1
  roles:
   - role: apache
   - role: wordpress
```


### Role Mariadb

```none
roles
└── mariadb
    ├── defaults
    │   └── main.yaml
    └── tasks
        ├── add-database.yaml
        ├── install.yaml
        └── main.yaml
```


<!-- .slide: data-state="medium-code" -->
`roles/mariadb/tasks/install.yaml`
```yaml
- name: Installation of mariadb-server package
  yum:
    name: mariadb-server
    state: present
    update_cache: yes

- name: Ensure mariadb-server is running (and enabled at boot)
  service:
    name: mariadb
    state: started
    enabled: yes

- name: Allow mariadb traffic on port 3306
  firewalld:
    service: mysql
    permanent: true
    state: enabled
    immediate: yes
```


<!-- .slide: data-state="medium-code" -->
`roles/mariadb/tasks/add-database.yaml`
```yaml
- name: Installation of MySQL-python package
  # package required to use ansible mysql modules
  yum:
    name: MySQL-python
    state: present
    update_cache: yes

- name: Create a new database with name '{{ DB_NAME }}'
  mysql_db:
    name: '{{ DB_NAME }}'
    state: present

- name: Create a new user with name '{{ DB_USER }}'
        with full access to '{{ DB_NAME }} from '{{ WEB_HOST }}'
  mysql_user:
    name: '{{ DB_USER }}'
    password: '{{ DB_PASSWORD }}'
    priv: '{{ DB_NAME }}.*:ALL'
    host: '{{ WEB_HOST }}'
    state: present
```


<!-- .slide: data-state="medium-code" -->
`roles/mariadb/tasks/main.yaml`
```yaml
- import_tasks: install.yaml
- import_tasks: add-database.yaml
```


`roles/mariadb/defaults/main.yaml`
```yaml
DB_NAME: bob
DB_USER: mydb
DB_PASSWORD: 12345678
WEB_HOST: localhost
```
Les valeurs par défaut du role.


### Role Apache

```none
roles
└── apache
    ├── handlers
    │   └── main.yaml
    └── tasks
        └── main.yaml
```


<!-- .slide: data-state="medium-code" -->
`roles/apache/tasks/main.yaml`
```yaml
- name: Installation of apache package
  yum:
    name: httpd
    state: present
    update_cache: yes

- name: Installation of php package
  yum:
    name: php
    state: present
    update_cache: yes

- name: Installation of php-mysql package
  yum:
    name: php-mysql
    state: present
    update_cache: yes

- name: Installation of wget package
  yum:
    name: wget
    state: present
    update_cache: yes

- name: Ensure apache is running (and enabled at boot)
  service:
    name: httpd
    state: started
    enabled: yes

- name: Allow http traffic on port 80
  firewalld:
    service: http
    permanent: true
    state: enabled
    immediate: yes
```


### Role Wordpress

```none
roles
└── wordpress
    └── tasks
        ├── configure.yaml
        ├── install.yaml
        └── main.yaml
```


<!-- .slide: data-state="medium-code" -->
`roles/wordpress/tasks/install.yaml`
```yaml
- name: Download wordpress archive
  get_url:
    url: https://wordpress.org/latest.tar.gz
    dest: /var/www/html/wordpress.tar.gz
    mode: 0440

- name: Untar wordpress archive
  unarchive:
    src: /var/www/html/wordpress.tar.gz
    dest: /var/www/html
    remote_src: true

- name: Remove wordpress archive
  file:
    path: /var/www/html/wordpress.tar.gz
    state: absent
```


<!-- .slide: data-state="medium-code" -->
`roles/wordpress/tasks/configure.yaml`
```yaml
- name: Create wordpress configuration file
  copy:
    src: /var/www/html/wordpress/wp-config-sample.php
    dest: /var/www/html/wordpress/wp-config.php
    remote_src: true

- name: Update wordpress configuration file with db name
  replace:
    dest: /var/www/html/wordpress/wp-config.php
    regexp: 'database_name_here'
    replace: '{{ DB_NAME }}'

- name: Update wordpress configuration file with user name
  replace:
    dest: /var/www/html/wordpress/wp-config.php
    regexp: 'username_here'
    replace: '{{ DB_USER }}'

- name: Update wordpress configuration file with user password
  replace:
    dest: /var/www/html/wordpress/wp-config.php
    regexp: 'password_here'
    replace: '{{ DB_PASSWORD }}'

- name: Update wordpress configuration file with host
  replace:
    dest: /var/www/html/wordpress/wp-config.php
    regexp: 'localhost'
    replace: '{{ DB_HOST }}'
```


<!-- .slide: data-state="medium-code" -->
`roles/wordpress/tasks/main.yaml`
```yaml
- import_tasks: install.yaml
- import_tasks: configure.yaml
```


<!-- .slide: data-state="medium-code" -->
* Générer un mot de passe aléatoirement pour l'accès à la base de données.

* Exemple :

```yaml
tasks:
  - name: Generate random password
    set_fact:
      password: "{{ lookup('password', 'password.txt') }}"

  - debug:
      msg: "Randomly generated password is : {{ password }}"
```


`apache-wordpress-mariadb-roles-password.yaml`
<!-- .slide: data-state="medium-code" -->
```yaml
- hosts: centos7
  tasks:
    - name: Generate random password for DB access
      set_fact:
        DB_PASSWORD: "{{ lookup('password', 'passwords.txt') }}"

- hosts: ansible-2
  roles:
   - role: mariadb-install
   - role: mariadb-configure

- hosts: ansible-1
  roles:
   - role: apache-install
   - role: wordpress-install
   - role: wordpress-configure
```

```none
$ ls -l passwords.txt
-rw------- 1 ansible ansible 21 oct.  29 16:48 passwords.txt
```
```none
$ cat passwords.txt
f2OLcLega8W,GC6vDiLn
```