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What is an Ansible inventory, and what is the difference between static and dynamic inventory?

Infrastructure as Code (Terraform, Ansible) · Intermediate level

Answer

An Ansible inventory lists the hosts and groups Ansible can manage. Static inventory is a file in INI or YAML. Dynamic inventory is generated from an external source such as AWS, Azure, GCP, VMware, or CMDB, so host lists and metadata stay current automatically.

Technical explanation

Inventory groups model roles, environments, regions, and lifecycle stages.

Dynamic inventory prevents stale host lists when instances scale up or down.

Inventory variables should describe differences, not hide application logic.

Prefer idempotent modules over shell so repeated runs are safe and change reporting is meaningful.

Separate reusable role logic from inventory-specific variables so the same automation works across environments.

Run lint, syntax checks, check mode where useful, and staged rollouts before production-wide changes.

Hands-on example

1. Create a minimal Ansible control workflow for: What is an Ansible inventory, and what is the difference between static and dynamic inventory?

2. Inventory example:

[web]

web1 ansible_host=10.0.1.10 ansible_user=ec2-user

web2 ansible_host=10.0.1.11 ansible_user=ec2-user

[web:vars]

ansible_become=true

3. Playbook example:

---

- name: Configure web hosts

hosts: web

become: true

tasks:

- name: Ensure nginx is installed

ansible.builtin.package:

name: nginx

state: present

- name: Ensure nginx is running

ansible.builtin.service:

name: nginx

state: started

enabled: true

4. Run ansible -m ping web first, then ansible-playbook site.yml --check --diff, then the real run.

More Infrastructure as Code (Terraform, Ansible) interview questions

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• What is the difference between declarative and imperative IaC, and where do Terraform and Ansible fall?
• What is the difference between configuration management and provisioning?
• What is Terraform, and what is the core plan/apply workflow?
• What does terraform init do?
• What is the Terraform state file, and why is it critical?
• Why should state be stored remotely, and what backend would you use on AWS?
• What is state locking, and why does it matter for teams?

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