# Web Server Cookbook - Conversion Guide
This document shows how the Chef cookbook converts to Ansible playbook structure.
## Overview
**Chef Cookbook**: `web-server`
**Ansible Role**: `web_server`
## File Mapping
### Metadata
- Chef: `metadata.rb` → Ansible: `meta/main.yml`
### Attributes
- Chef: `attributes/default.rb` → Ansible: `defaults/main.yml`
### Recipes
- Chef: `recipes/default.rb` → Ansible: `tasks/main.yml`
### Templates
- Chef: `templates/default/*.erb` → Ansible: `templates/*.j2`
### Custom Resources
- Chef: `resources/nginx_vhost.rb` → Ansible: Custom module or included task file
## Conversion Examples
### 1. Package Installation
**Chef:**
```ruby
package node['nginx']['package_name'] do
version node['nginx']['version'] unless node['nginx']['version'].nil?
action :install
end
```
**Ansible:**
```yaml
- name: Install nginx
ansible.builtin.package:
name: "{{ nginx_package_name }}"
state: present
version: "{{ nginx_version | default(omit) }}"
```
### 2. Service Management
**Chef:**
```ruby
service node['nginx']['service_name'] do
supports status: true, restart: true, reload: true
action [:enable, :start]
subscribes :restart, "package[#{node['nginx']['package_name']}]", :immediately
end
```
**Ansible:**
```yaml
- name: Enable and start nginx service
ansible.builtin.service:
name: "{{ nginx_service_name }}"
state: started
enabled: true
notify: restart nginx
```
### 3. Template Rendering
**Chef:**
```ruby
template "#{node['nginx']['conf_dir']}/nginx.conf" do
source 'nginx.conf.erb'
owner 'root'
group 'root'
mode '0644'
variables(
worker_processes: node['nginx']['worker_processes'],
worker_connections: node['nginx']['worker_connections']
)
notifies :reload, 'service[nginx]', :delayed
end
```
**Ansible:**
```yaml
- name: Configure nginx
ansible.builtin.template:
src: nginx.conf.j2
dest: "{{ nginx_conf_dir }}/nginx.conf"
owner: root
group: root
mode: '0644'
notify: reload nginx
```
### 4. Conditional Resources (Guards)
**Chef:**
```ruby
file node['nginx']['ssl']['cert_path'] do
content '# SSL certificate goes here'
owner 'root'
group 'root'
mode '0644'
action :create
only_if { node['environment'] == 'development' }
end
```
**Ansible:**
```yaml
- name: Create SSL certificate placeholder
ansible.builtin.file:
path: "{{ nginx_ssl_cert_path }}"
state: file
owner: root
group: root
mode: '0644'
when: environment == 'development'
```
### 5. Platform-Specific Logic
**Chef:**
```ruby
case node['platform_family']
when 'debian'
execute 'enable-ufw-http' do
command 'ufw allow 80/tcp'
action :run
only_if 'which ufw'
end
when 'rhel'
execute 'enable-firewalld-http' do
command 'firewall-cmd --permanent --add-service=http'
action :run
only_if 'systemctl is-active firewalld'
end
end
```
**Ansible:**
```yaml
- name: Enable HTTP in UFW (Debian)
community.general.ufw:
rule: allow
port: '80'
proto: tcp
when: ansible_os_family == 'Debian'
- name: Enable HTTP in firewalld (RHEL)
ansible.posix.firewalld:
service: http
permanent: true
state: enabled
when: ansible_os_family == 'RedHat'
notify: reload firewalld
```
### 6. Custom Resource Usage
**Chef:**
```ruby
nginx_vhost 'example-app' do
server_name 'app.example.com'
port 8080
root_dir '/var/www/apps/example'
ssl_enabled false
action :create
end
```
**Ansible (using include_role or include_tasks):**
```yaml
- name: Configure nginx virtual host for example-app
include_tasks: nginx_vhost.yml
vars:
vhost_name: example-app
vhost_server_name: app.example.com
vhost_port: 8080
vhost_root_dir: /var/www/apps/example
vhost_ssl_enabled: false
```
### 7. Notifications and Handlers
**Chef:**
```ruby
template '/etc/nginx/nginx.conf' do
source 'nginx.conf.erb'
notifies :reload, 'service[nginx]', :delayed
end
service 'nginx' do
action [:enable, :start]
end
```
**Ansible:**
```yaml
# tasks/main.yml
- name: Configure nginx
ansible.builtin.template:
src: nginx.conf.j2
dest: /etc/nginx/nginx.conf
notify: reload nginx
# handlers/main.yml
- name: reload nginx
ansible.builtin.service:
name: nginx
state: reloaded
```
## Complete Playbook Structure
```
web_server/
├── meta/
│ └── main.yml # Dependencies and role info
├── defaults/
│ └── main.yml # Default variables
├── vars/
│ └── main.yml # Other variables
├── tasks/
│ ├── main.yml # Main tasks
│ ├── install.yml # Installation tasks
│ ├── configure.yml # Configuration tasks
│ └── nginx_vhost.yml # Virtual host management
├── templates/
│ ├── nginx.conf.j2
│ └── default-site.conf.j2
├── handlers/
│ └── main.yml # Service handlers
└── files/
└── check-nginx.sh # Static files
```
## Notes
1. **Idempotency**: Both Chef and Ansible are idempotent, but Ansible makes this more explicit
2. **Testing**: Chef uses Test Kitchen; Ansible uses Molecule
3. **Attributes vs Variables**: Chef attributes map to Ansible variables
4. **Resources vs Modules**: Chef resources map to Ansible modules
5. **Custom Resources**: May need custom Ansible modules or reusable task files
