Postman & Ansible in Network Automation

Professional Guide for IT Engineers & Network Specialists

Postman in Networking

What is Postman?

Postman is a powerful API development and testing platform that enables engineers to send HTTP requests, automate API testing, document APIs, and debug HTTP/HTTPS interactions. It is widely used in networking for testing programmable interfaces of devices, controllers, and cloud platforms.

Postman Interface Overview

• Collections: Organize related API requests (GET, POST, PUT, DELETE) into reusable groups.
• Requests: Define individual HTTP requests—method, URL, headers, body, and authentication.
• Environments: Store variables (endpoints, tokens) for switching between test/dev/prod setups.
• Workspaces: Manage personal or team projects and facilitate collaboration.

Creating and Sending Requests

• HTTP Methods Supported: GET (retrieve), POST (create), PUT (update), DELETE (remove).
• Headers: Set authentication tokens, content types, and other metadata.
• Body: Attach JSON, XML, or form-data for POST/PUT requests.
• Parameters: Add query parameters for filtering API data.

Method: GET
URL: https://api.network.com/devices/1
Headers: Authorization: Bearer <token>
      

Using Variables and Environments

• Variables: Use placeholders (e.g., {{base_url}}, {{token}}) to make requests reusable.
• Environments: Define variable sets for each environment (test, staging, production).

Testing and Automation

• Test Scripts: Validate response data, status codes, and automate workflows using JavaScript in the “Tests” tab.
• Automated Monitoring: Schedule API tests to run at intervals.

pm.test("Status code is 200", function () {
  pm.response.to.have.status(200);
});
    

Collection Runner & Newman

• Collection Runner: Run API request collections in sequence, with variable data sets.
• Newman: Command-line tool to execute Postman collections—integrate with CI/CD pipelines and automation tools.

newman run MyCollection.json -e ProdEnv.json
    

Collaboration & Debugging

• Sharing: Share collections/environments with your team or partners.
• Team Workspaces: Collaborate, maintain version control, and comment on requests.
• Request/Response Viewer: Inspect HTTP requests, responses, headers, and troubleshoot errors efficiently.

Key Points & Exam Tips

• Postman is essential for REST API development, testing, and troubleshooting programmable network devices.
• Supports automation, variables, environments, and robust collaboration.
• Use variables for endpoints/credentials and always validate responses.
• Leverage collection runner and Newman for bulk and regression testing.

Sample Network Automation Scenario with Postman

{
  "vlanId": 200,
  "vlanName": "Engineering"
}
    

Ansible in Networking

What is Ansible?

Ansible is an open-source automation platform used for configuration management, software deployment, and network automation. It is agentless—no software is required on the managed devices.

Core Concepts

Ansible Architecture

• Control Node: Where Ansible runs (admin PC or CI/CD server).
• Managed Nodes: Devices being configured (no agent required, uses SSH/API).
• Agentless: No software to install on network devices.

Writing Playbooks (YAML Syntax)

- hosts: switches
  tasks:
    - name: Create VLAN 100
      ios_config:
        lines: vlan 100
    

• Use variables for device IPs, credentials, VLANs, etc.
• Templates (Jinja2) allow dynamic generation of configs.

Executing Playbooks

ansible-playbook playbook.yml
ansible-playbook playbook.yml --limit switches
    

Commonly Used Modules

• ios_config: Manage Cisco IOS configurations.
• nxos_config: Manage Cisco NX-OS devices.
• eos_config: Manage Arista EOS devices.
• file, apt, yum, service (for general server automation).

Security and Best Practices

• Use SSH keys for device authentication.
• Encrypt secrets (passwords, tokens) with Ansible Vault.
• Debug with -v or -vvv for verbose output.

Troubleshooting and CI/CD Integration

• Common issues: SSH/auth failures, YAML errors, module not found.
• Integrate Ansible with Jenkins, GitLab, or Azure DevOps for automated deployments and tests.

Sample Ansible Playbook – VLAN Automation

[switches]
switch1 ansible_host=192.168.1.10 ansible_network_os=ios ansible_user=admin ansible_password=your_password
      

---
- name: Configure VLAN on Cisco Switch
  hosts: switches
  gather_facts: no

  tasks:
    - name: Create VLAN 200
      ios_config:
        lines:
          - vlan 200
          - name Engineering
      

ansible-playbook -i inventory.ini vlan_config.yml
      

Key Points & Exam Tips

• Understand playbook structure, inventory, and modules.
• Ansible is agentless, idempotent, and designed for repeatable, large-scale automation.
• Be able to read basic YAML and playbooks.
• Ideal for automating and standardizing network operations across multi-vendor environments.

Postman and Ansible Networking Quiz

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