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⚡ Ansible Ad-hoc & Modules — Ad-hoc commands, essential modules, Jinja2 templating

📋 Reference

💡 Example

# ── Ad-hoc commands ──────────────────────────────────────────
# Test connectivity
ansible all -i inventory -m ping

# Run command on all web servers
ansible webservers -i inventory -m command -a "uptime" -u ubuntu

# Get disk usage
ansible all -i inventory -m shell -a "df -h | tail -1" -b

# Install package
ansible webservers -i inventory -m apt \
  -a "name=apache2 state=present update_cache=yes" -b

# Copy file
ansible webservers -i inventory -m copy \
  -a "src=index.html dest=/var/www/html/index.html owner=www-data mode=0644" -b

# Restart service
ansible webservers -i inventory -m service \
  -a "name=apache2 state=restarted" -b

# Create user
ansible all -i inventory -m user \
  -a "name=deploy groups=www-data shell=/bin/bash state=present" -b

# Get all facts
ansible web01 -i inventory -m setup | head -50

# ── Jinja2 Templates ──────────────────────────────────────────
# templates/apache.conf.j2
cat > /tmp/apache.conf.j2 << 'TEMPLATE'
# Generated by Ansible — {{ ansible_managed }}
# Host: {{ inventory_hostname }}
# Date: {{ ansible_date_time.date }}

<VirtualHost *:{{ app_port | default(80) }}>
    ServerName  {{ server_name | default(ansible_fqdn) }}
    ServerAdmin {{ admin_email | default("webmaster@" + ansible_domain) }}
    DocumentRoot {{ app_dir }}

    {% if enable_https | default(false) %}
    # Redirect HTTP to HTTPS
    RewriteEngine On
    RewriteRule ^(.*)$ https://%{HTTP_HOST}$1 [R=301,L]
    {% endif %}

    {% for alias in server_aliases | default([]) %}
    ServerAlias {{ alias }}
    {% endfor %}

    <Directory {{ app_dir }}>
        Options +ExecCGI {% if disable_indexes | default(true) %}-Indexes{% endif %}
        AllowOverride {{ allow_override | default('All') }}
        Require all granted
    </Directory>

    ErrorLog  ${APACHE_LOG_DIR}/{{ app_name }}_error.log
    CustomLog ${APACHE_LOG_DIR}/{{ app_name }}_access.log \
      {% if log_format is defined %}{{ log_format }}{% else %}combined{% endif %}

</VirtualHost>
TEMPLATE

# ── Common Playbook Patterns ──────────────────────────────────
cat > /tmp/patterns.yml << 'YAML'
---
- name: Deployment patterns
  hosts: webservers
  become: true

  tasks:
    # Register + debug
    - name: Get disk usage
      ansible.builtin.shell: df -h / | awk 'NR==2{print $5}'
      register: disk_usage
      changed_when: false

    - name: Show disk usage
      ansible.builtin.debug:
        msg: "{{ inventory_hostname }} disk: {{ disk_usage.stdout }}"

    # Conditional
    - name: Install Apache (Debian only)
      ansible.builtin.apt:
        name: apache2
        state: present
      when: ansible_os_family == 'Debian'

    - name: Install httpd (RedHat only)
      ansible.builtin.yum:
        name: httpd
        state: present
      when: ansible_os_family == 'RedHat'

    # Loop with dict
    - name: Create app directories
      ansible.builtin.file:
        path:  "{{ item.path }}"
        owner: "{{ item.owner }}"
        mode:  "{{ item.mode }}"
        state: directory
      loop:
        - { path: /var/www/html,    owner: www-data, mode: '0755' }
        - { path: /var/log/app,     owner: www-data, mode: '0750' }
        - { path: /etc/app/conf.d,  owner: root,     mode: '0755' }

    # Block with rescue
    - name: Deploy application
      block:
        - name: Pull latest code
          ansible.builtin.git:
            repo:    https://github.com/myorg/myapp.git
            dest:    /var/www/html
            version: main
        - name: Restart service
          ansible.builtin.service:
            name: apache2
            state: restarted
      rescue:
        - name: Rollback on failure
          ansible.builtin.command: git -C /var/www/html checkout HEAD~1
        - name: Notify on failure
          ansible.builtin.debug:
            msg: "Deployment failed on {{ inventory_hostname }} — rolled back"
YAML
echo "Patterns written to /tmp/patterns.yml"

# Run: ansible-playbook -i inventory patterns.yml -v

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