Inventory Manager

Quick Start

Organize Ansible inventory with proper host groups, variables, and dynamic inventory sources.

Instructions

Step 1: Create static inventory

INI format:

inventory/production

[webservers] web1 ansible_host=192.168.1.10 web2 ansible_host=192.168.1.11

[databases] db1 ansible_host=192.168.1.20 db2 ansible_host=192.168.1.21

[loadbalancers] lb1 ansible_host=192.168.1.30

[production:children] webservers databases loadbalancers

[production:vars] ansible_user=deploy ansible_python_interpreter=/usr/bin/python3 environment=production

YAML format:

inventory/production.yml

all: children: production: children: webservers: hosts: web1: ansible_host: 192.168.1.10 web2: ansible_host: 192.168.1.11 databases: hosts: db1: ansible_host: 192.168.1.20 db2: ansible_host: 192.168.1.21 loadbalancers: hosts: lb1: ansible_host: 192.168.1.30 vars: ansible_user: deploy environment: production

Step 2: Organize group variables

Directory structure:

inventory/ ├── production ├── staging ├── group_vars/ │ ├── all.yml │ ├── webservers.yml │ ├── databases.yml │ └── production.yml └── host_vars/ ├── web1.yml └── db1.yml

group_vars/all.yml:

Variables for all hosts

ansible_python_interpreter: /usr/bin/python3 ntp_servers:

• 0.pool.ntp.org
• 1.pool.ntp.org

group_vars/webservers.yml:

Variables for webservers group

nginx_port: 80 nginx_worker_processes: 4 app_directory: /var/www/app

group_vars/production.yml:

Variables for production environment

environment: production backup_enabled: true monitoring_enabled: true

Step 3: Configure host-specific variables

host_vars/web1.yml:

nginx_worker_connections: 1024 server_id: 1

Step 4: Use inventory in playbooks

Run playbook with specific inventory

ansible-playbook -i inventory/production site.yml

Target specific group

ansible-playbook -i inventory/production site.yml --limit webservers

Target specific host

ansible-playbook -i inventory/production site.yml --limit web1

Dynamic Inventory

AWS EC2 Plugin

inventory/aws_ec2.yml:

plugin: amazon.aws.aws_ec2 regions:

• us-east-1
• us-west-2

filters: tag:Environment: production instance-state-name: running

keyed_groups:

• key: tags.Role prefix: role
• key: tags.Environment prefix: env
• key: placement.availability_zone prefix: az

hostnames:

• tag:Name
• private-ip-address

compose: ansible_host: private_ip_address

Azure Plugin

inventory/azure_rm.yml:

plugin: azure.azcollection.azure_rm include_vm_resource_groups:

• production-rg

keyed_groups:

• key: tags.role prefix: role
• key: tags.environment prefix: env

conditional_groups: webservers: "'web' in tags.role" databases: "'db' in tags.role"

Custom Script

inventory/custom.py:

#!/usr/bin/env python3 import json

inventory = { "webservers": { "hosts": ["web1", "web2"], "vars": { "nginx_port": 80 } }, "databases": { "hosts": ["db1", "db2"] }, "_meta": { "hostvars": { "web1": {"ansible_host": "192.168.1.10"}, "web2": {"ansible_host": "192.168.1.11"}, "db1": {"ansible_host": "192.168.1.20"}, "db2": {"ansible_host": "192.168.1.21"} } } }

print(json.dumps(inventory))

Inventory Patterns

All hosts:

ansible all -i inventory/production -m ping

Specific group:

ansible webservers -i inventory/production -m ping

Multiple groups:

ansible 'webservers:databases' -i inventory/production -m ping

Exclude group:

ansible 'all:!databases' -i inventory/production -m ping

Intersection:

ansible 'webservers:&production' -i inventory/production -m ping

Regex:

ansible '~web.*' -i inventory/production -m ping

Multi-Environment Setup

inventory/ ├── production/ │ ├── hosts │ ├── group_vars/ │ │ ├── all.yml │ │ └── webservers.yml │ └── host_vars/ ├── staging/ │ ├── hosts │ ├── group_vars/ │ │ ├── all.yml │ │ └── webservers.yml │ └── host_vars/ └── development/ ├── hosts └── group_vars/ └── all.yml

Usage:

Production

ansible-playbook -i inventory/production site.yml

Staging

ansible-playbook -i inventory/staging site.yml

Development

ansible-playbook -i inventory/development site.yml

Best Practices

• Organize inventory by environment

• Use group_vars for shared configuration

• Use host_vars for host-specific settings

• Document inventory structure

• Use dynamic inventory for cloud resources

• Keep sensitive data in Ansible Vault

• Use meaningful group names

• Implement proper variable precedence